AN EVALUATION OF THE USE OF SELF-CONSOLIDATING CONCRETE (SCC) 
FOR DRILLED SHAFT APPLICATIONS 
 
 
Except where reference is made to the work of others, the work described in this thesis is 
my own or was done in collaboration with my advisory committee.  This thesis does not 
include proprietary or classified information.  
 
 
 
 
 
 
 
Joseph Donald Bailey 
 
 
 
 
 
Certificate of Approval: 
 
 
 
 
 
Dan A. Brown                                                                                   Anton K. Schindler 
Gottlieb Associate Professor                                                             Assistant Professor  
Civil Engineering                                                                              Civil Engineering  
 
 
 
 
 
George E. Ramey                                                                               Stephen L. McFarland 
Professor                                                                                            Dean 
Civil Engineering                                                                               Graduate School  
 
i 
AN EVALUATION OF THE USE OF SELF-CONSOLIDATING CONCRETE (SCC) 
FOR DRILLED SHAFT APPLICATIONS 
 
 
 
 
 
Joseph Donald Bailey  
 
 
 
 
 
A Thesis 
Submitted to 
The Graduate Faculty of 
Auburn University 
In Partial Fulfillment of the 
Requirements for the 
Degree of 
Master of Science  
 
 
 
 
 
 
Auburn University 
 
August 8, 2005 
 
 
ii ii
 
AN EVALUATION OF THE USE OF SELF-CONSOLIDATING CONCRETE (SCC) 
FOR DRILLED SHAFT APPLICATIONS 
 
 
 
Joseph Donald Bailey 
 
 
Permission is granted to Auburn University to make copies of this thesis at its discretion, 
upon the request of individuals or institutions and at their expense.  The author reserves 
all publication rights.   
 
 
 
 
                                                                    Signature of Author  
 
 
 
                                            Date 
 
 
 
 
 
 
Copy sent to: 
  
               Name                                                                                              Date  
 
 
 
 
 
 
 
 
 
 
 
iii iii
AN EVALUATION OF THE USE OF SELF-CONSOLIDATING CONCRETE (SCC) 
FOR DRILLED SHAFT APPLICATIONS 
 
 
Joseph Donald Bailey 
 
Master of Science, August 8, 2005 
(B.S. Auburn University 2002) 
 
234 Typed Pages 
 
Directed by Dr. Anton K. Schindler and Dr. Dan. A. Brown 
 
 
In drilled shaft construction, the recent development of sophisticated techniques 
for integrity and load testing has lead to the ability to asses the quality of drilled shaft 
foundations in terms of integrity and load carrying capabilities after they have been cast.  
Although this ability has lead to better assessment of drilled shaft foundations, it has also 
given insight to problems that are associated with materials and construction practices 
that has lead to defects or less than optimal performance for drilled shaft foundations.  
This study examines the more common problems associated with drilled shaft 
foundations to emphasize the importance of constructability in design and workability in 
the construction materials.  The majority of these problems consist of the failure to 
adequately consider one or more of the following issues:
iv iv
? Workability of concrete for the duration of the pour  
? Compatibility of the highly congested rebar cages and concrete being placed   
? Bleeding and segregation 
The main purpose of this study is to evaluate the use of self-consolidating 
concrete (SCC) as a viable material to overcome these issues due to its high flowability, 
passing ability, resistance to segregation, and reduced bleeding.  A laboratory study will 
examine the difference between ordinary drilled shaft concrete and self-consolidating 
concrete (SCC) for both fresh and hardened properties.  The fresh properties include 
filling ability, passing ability, segregation resistance, workability over time, bleeding 
characteristics, and controlled setting, while the hardened properties include the 
comparison of the compressive strength, elastic modulus, drying shrinkage, and 
permeability.   
The laboratory results for both the ordinary drilled shaft concrete (ODSC) and 
SCC mixtures were evaluated and compared.  The results show that SCC can be used to 
address many of the problems associated with drilled shaft construction because of the 
inherent workability, passing ability, resistance to segregation, and reduced bleeding of 
this type of concrete.  Furthermore, the data suggest that the use of SCC in drilled shaft 
applications can provide similar or improved hardened concrete properties, which 
includes the compressive strength, elastic modulus, drying shrinkage, and permeability.  
However, some potential concerns for this material in drilled shaft applications include 
the general and overall lack of experience and research, lack of standardized tests, lack of 
well-defined mixture proportioning, and larger changes in workability compared to 
ODSC mixtures. 
v 
 
Style manual or journal used The Chicago Manual of Style 
 
 
 
 
Computer software used Microsoft Word, Microsoft Excel, Microsoft Powerpoint 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
vi 
 
 
 
 
 
 
TABLE OF CONTENTS 
 
LIST OF TABLES ?.??????????????????????????.x 
 
LIST OF FIGURES ???????????????..??????????....xii 
 
CHAPTER ONE: INTRODUCTION????????????????????..1   
1.1  Statement of problem??????????????????????1 
1.2  Research Objectives??????...?...???????.??????...3 
1.3  Research Scope??.??.?..??????????????????.4 
 
CHAPTER TWO:  SELF-CONSOLIDATING CONCRETE???????????.5 
2.1 Introduction?????????????????????????...5 
2.2 SCC Testing Procedures???????????????????...?7 
2.2.1  Slump Flow Test 
2.2.2  L- Box Test 
2.2.3  J-Ring Test 
2.2.4  Segregation Column Test 
 2.3  Fresh Concrete Properties???????????...????????18 
  2.3.1  Rheology 
  2.3.2  Filling Ability 
  2.3.3  Passing Ability 
  2.3.4  Segregation Resistance  
 2.4  Hardened Concrete Properties????????????????...?.29 
  2.4.1  Compressive Strength 
  2.4.2  Modulus of Elasticity  
  2.4.3  Drying Shrinkage 
  2.4.4  Permeability  
2.5   Summary and Conclusions.???..??????????...????..48 
CHAPTER THREE: EXPERIENCES WITH DRILLED SHAFT CONCRETE???.52 
3.1 Introduction????...??.??????????????????.52 
3.2 Workability of Drilled Shaft Concrete???????????????53 
3.3 Compatibility between Congested Rebar Cages and Concrete?????...74 
vii vii
3.4 Segregation and Bleeding???????????????????...81 
3.5 Summary and Conclusions??????????????????.....87 
 
CHAPTER FOUR: LABORATORY TESTING PROGRAM AND MATERIALS ?...89 
4.1 Introduction ????????????????????????....89 
4.2 Requirements for ODSC and SCC Mixtures ???????????.....89 
4.3 Laboratory Testing Program ?????????????????.?.91 
4.3.1 Phase I ? Effect of Type and Dosage of HRWRA 
4.3.2 Phase II ? Effect of Retarder Dosage 
4.3.3 Phase III ? Appropriate SCC Mixing Procedure 
4.3.4 Phase IV ? Selection of SCC Properties  
4.3.5 Phase V ? Methods to Modify the Viscosity of SCC Mixtures  
4.4  Raw Material Sources??????????????????......?.112 
   4.4.1 Cementitious Materials 
4.4.2 Aggregates  
4.4.3 Chemical Admixtures  
 
 CHAPTER FIVE: LABORATORY EQUIPMENT, SPECIMENS, AND  
PROCEDURES ????????????????????.???????.126 
 5.1 Introduction ????????????????????...?....?....126 
 5.2 Batching and Mixing Procedure ???????????????...?127 
5.3 Fresh Property Testing ????????????????????..129 
5.3.1 Slump Test 
5.3.2 Slump Flow Test 
5.3.3 J-Ring Test  
5.3.4 L-Box Test 
5.3.5 Segregation Column Test 
5.3.6 Bleeding 
5.3.7 Unit Weight and Air Content 
5.3.8 Making and Curing Specimens 
5.3.9 Time of Set  
5.4 Hardened Concrete Properties ?????????????????..145 
5.4.1 Compressive Strength 
5.4.2 Modulus of Elasticity  
5.4.3 Drying Shrinkage  
5.4.4 Permeability  
 
 
viii 
CHAPTER SIX: PRESENTATION AND ANALYSIS OF RESULTS ?????....151 
 6.1 Introduction ?????...???????????????????151 
 6.2 Phase I - Selection of Type and Dosage of HWRWA ????????..151 
6.3 Phase II ? Effect of Retarder Dosage ???????????????153 
6.4 Phase III - Appropriate SCC Mixing Procedure ???????...???156 
6.5 Phase IV - Selection of SCC Properties ??????????.???...158 
  6.5.1 Fresh Concrete Properties and Workability 
  6.5.2 Segregation and Bleeding Results   
  6.5.3 Passing Ability: J-Ring and L-Box 
6.5.4 Compressive Strength  
6.5.5 Modulus of Elasticity 
6.5.6 Drying Shrinkage 
6.5.7 Permeability   
  6.5.8 Comparison between Laboratory and Field Conditions  
6.6 Phase V - Methods to Modify the Viscosity of SCC Mixtures ???.?....190 
  6.6.1 Fresh Concrete Properties 
                        6.6.2 Hardened Concrete Properties  
                        6.6.3 Effect of VMA on Fresh Concrete Properties  
 6.7 Summary of Research Findings?????????????????.210 
CHAPTER SEVEN: PROPOSED EXPERIMENTAL FIELD STUDY.?????...214 
 7.1 Introduction ???????????????????????......214 
 7.2 Test Shafts ????????????...???????????.....215 
 7.3 Fresh Concrete Property Testing ????????????????..215 
 7.4 Hardened Concrete Property Testing ????????????.??...216 
 7.5 Placement Monitoring ????????????????????...217 
 7.6 Testing of Non-exhumed Shafts ???????????????.?..217 
 7.7 Testing of Exhumed Shafts ??????????????????...218 
            7.8 Instrumentation ??????????????????????.....218 
CHAPTER EIGHT: SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS.219 
            8.1 Introduction???????????????????????...?219 
 8.2 Summary and Conclusions ??????????????????...219 
 8.3 Recommendations??????????????????????.222 
 
 
ix 
 
 
 
LIST OF TABLES 
 
Table 2.1        Visual Stability Index (VSI) Rating??????????..????.12 
Table 2.2        J-Ring Passing Ability Rating?????????????????15 
Table 2.3       Compressive Strength Results from Turcry et al.(2003)............................35 
Table 2.4       Mixture Proportions (Kim et al. 1998)....................................................... 43 
Table 4.1       Concrete Mixture Proportions for Phase I ???????????.....93 
 
Table 4.2       Concrete Mixture Proportions for Phase II ????????????95 
Table 4.3       Concrete Mixture Proportions for Phase III ???????????..98 
Table 4.4       Concrete Mixture Proportions for Phase IV ???????????.103 
Table 4.5       Concrete Mixture Proportions for Phase V ??????????......110 
Table 4.6       Chemical Analysis Results for the Giant Type I Cement ??????113 
Table 4.7       Chemical Analysis Results for the SEFA Group Class F Fly Ash ??..114 
Table 4.8       Chemical Analysis Results for the Micron 3 Fly Ash ???????..115 
Table 4.9       Specific Gravities for Cementitious Materials ??????????.116 
Table 4.10     Specific Gravities and Absorption Capacities for Aggregate Sources ?.120 
Table 5.1        Visual Stability Index (VSI) Rating ??????????????133 
Table 5.2        J-Ring Passing Ability Rating ???????.?????????136 
Table 6.1        Fresh Concrete Properties for Phase I ?????????????.152 
 
Table 6.2        Fresh Concrete Properties for Phase II ?????????????155 
 
Table 6.3        Fresh Concrete Properties for Phase III ????????????..157 
 
Table 6.4        Fresh Concrete Properties for ODSC Mixtures ?????????..159
x x
Table 6.5        Fresh Concrete Properties for SCC Mixtures ??????????.160 
 
Table 6.6        Segregation and Bleeding Results ??????????????..167 
Table 6.7        Passing Ability Results for SCC Mixtures ???????????.168 
 
Table 6.8        Fresh Concrete Properties for both Laboratory and Field Conditions ?185 
Table 6.9        Fresh Concrete Properties for Phase V ????????????...194 
 
Table 6.10      Tabulated Results of the Effect of VMA on Fresh Concrete Properties..209  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
xi 
 
 
 
 
 
LIST OF FIGURES 
Figure 2.1       Upright Slump Cone Method ??????.???????????9 
Figure 2.2       Inverted Slump Cone Method ????????????????....9 
Figure 2.3       Visual Stability Index Rating ????????...??.?????...12 
Figure 2.4       L-Box Testing Apparatus ??????????????????.14 
Figure 2.5       J-Ring Testing Apparatus ?????????????????.....15 
Figure 2.6       Segregation Column Testing Apparatus ?????????.???..17 
Figure 2.7       Bingham Fluid Model ???????????????????...19 
Figure 2.8       Mechanism of Blocking ???????????????????24 
Figure 2.9        Blocking Ratios versus Reinforcement Spacing for Different Size 
                         Aggregate ???????.?...???????????????.25 
Figure 2.10     Strength versus Cement-to-Water Ratio ????????????...30 
Figure 2.11     Compressive Strength versus Porosity ?????????????.31 
Figure 2.12     Strength versus Gel-to-Space Ratio Based on Tested Mortar Cubes??33 
 
Figure 2.13     Average Compressive Strengths of SCC and Conventional Bridge  
                        Concretes with w/c of 0.40 ?????????????????...34 
 
Figure 2.14     Elastic Modulus versus Sand-to-Aggregate Ratio ....................................38 
 
Figure 2.15     Aggregate Content versus Water-to-Cement Ratio ????????..40 
 
Figure 2.16     Shrinkage Modification Factor for Different Sand-to-Aggregate  
                        Ratios ??????????????????????????41 
 
Figure 2.17     Shrinkage versus Cement Content ...........................................................42 
 
Figure 2.18     Drying Shrinkage versus Age (Kim et al. 1998) ?????????..43 
xii xii
Figure 2.19     SCC versus Normal Concrete....................................................................44  
 
Figure 2.20    Drying Shrinkage versus Sand-to-Aggregate Ratio????????...45 
Figure 2.21     Coefficient of Permeability versus Capillary Porosity ???????.46 
Figure 2.22     Coefficient of Permeability versus Water-to-Cement Ratio ?????.46 
Figure 2.23     RCPT Values of SCC and Normal Concrete ???????????48 
Figure 3.1      Drilled Shaft Mixture with a Slump of Approximately 6.5 Inches ??...55 
 
Figure 3.2      Drilled Shaft Mixture with a Slump of 8-9 Inches ?????????56 
Figure 3.3      Illustration of Tremie Placement ???????????????...59 
Figure 3.4      Illustration of Entrapped Debris due to the Eruption of Fresh Concrete  
                       through Stiff Concrete ??.?????????????????..60 
 
Figure 3.5      Illustration of Entrapped Debris Seams due to Extraction of the Tremie..61 
Figure 3.6      Example 1 of Shaft Defects due to the Loss of Workability ?????.62 
Figure 3.7      Example 2 of Shaft Defects due to the Loss of Workability ?????.62 
Figure 3.8      Example 3 of Shaft Defects due to the Loss of Workability ?????.63 
Figure 3.9      Example 4 of Shaft Defects due to the Loss of Workability ?????.63 
Figure 3.10    Example 5 of Shaft Defects due to the Loss of Workability?????..64 
Figure 3.11    Illustration of a Cased Hole ?????????????????...65 
Figure 3.12    Necking and Arching due to the Extraction of the Casing when   
                       Workablility is Lost ??????????????.??????..66 
Figure 3.13    Shaft Defects due to the Extraction of the Casing ?????????.67 
Figure 3.14    Slump Loss versus Time Relationship ?????????????..68 
Figure 3.15    Slump Loss at 70
o 
F for Two Different Brands of Type I Cement ...??.69 
Figure 3.16    Shaft Defects due to the Loss of Workability (left), After Removal of 
                       Surface Flaws for Repairs ??????????????..????70 
Figure 3.17    Shaft Defects due to the Loss of Workability from Construction Delays..72 
xiii xiii
Figure 3.18    Screening of the Concrete due to Heavily Reinforced Rebar Cages ?.?76 
Figure 3.19    Elevation Difference between the Inside and Outside of a Rebar Cage  
                       due to Screening of the Concrete Flow ?????????????..77 
Figure 3.20    Shaft Defects due to the Screening of the Concrete Flow ??????.77 
 
Figure 3.21    Oval Shaped Column with Figure 8 Rebar Cage ?????????..79 
 
Figure 3.22    Shaft Defect due to Double Reinforcement Cages ?????????80 
Figure 3.23    Illustration of Bleeding in Freshly Placed Concrete ????????..84 
Figure 3.24    Example 1 of Bleed Channels and Surface Streaks due to Bleed Water 
                       Traveling along the Casing ??????????????????84 
Figure 3.25    Example 2 of Bleed Channels and Surface Streaks due to Bleed Water 
                       Traveling along the Casing ??????????????????85 
Figure 3.26    Shaft Defect due to Bleed Water Traveling along the Casing ????...86 
Figure 4.1       Flow Chart for Phase I ???????????????????..94 
Figure 4.2       Flow Chart for Phase II ???????????????????96 
Figure 4.3       Flow Chart for Phase III ??????????????????.100 
Figure 4.4       Example of Identification System for Ordinary Drilled Shaft Concrete 102 
Figure 4.5       Example of Identification System for SCC Mixtures ???????.102 
Figure 4.6       Flow Chart for Phase IV ??????????????????.106 
Figure 4.7       Example of Identification System for Phase V ?????????..108 
Figure 4.8       Flow Chart for Phase V ??????????????????..111 
Figure 4.9       Particle Size Analyzer ???????????????????117 
Figure 4.10     Laser Particle Size Analyzer Results ?????????????..118 
Figure 4.11     Raw Material being Delivered from South Carolina ???????..119 
Figure 4.12     No. 67 Coarse Aggregate Gradation for South Carolina Material ??.121 
 
Figure 4.13     No. 789 Coarse Aggregate Gradation for South Carolina Material ?...121 
xiv xiv
 
Figure 4.14     Fine Aggregate Gradation for South Carolina Material ??????.122 
 
Figure 4.15     No. 67 Coarse Aggregate Gradation for Alabama Material ????...122 
 
Figure 4.16     No. 89 Coarse Aggregate Gradation for Alabama Material ????...123 
 
Figure 4.17     Fine Aggregate Gradation for Alabama Material ????????...123 
 
Figure 5.1       New Indoor Mixing Facility ????????????????...127 
Figure 5.2       12 ft
3
 Concrete Mixer used for this Research ??????????.129 
Figure 5.3       Testing Equipment for Slump Test ??????????????.130 
Figure 5.4       Testing Equipment for Slump Flow Test ???????????...132 
Figure 5.5      Visual Stability Index Rating ????????????????..133 
Figure 5.6       Testing Equipment for J-Ring Test ??????????????135 
Figure 5.7       L-Box Dimensions ????????????????????..137 
Figure 5.8       Testing Equipment for L-Box Test ??????????????.137 
Figure 5.9     Testing Equipment for Segregation Column Test ?..???????..139 
Figure 5.10     Testing Equipment for Bleeding Test ?????????????.142 
Figure 5.11     Testing Equipment for Unit Weight and Air Content ???????143 
Figure 5.12     Testing Equipment for Time of Setting ????????????..145 
Figure 5.13     600 Kip Forney Compression Machine ????????.????.146 
Figure 5.14     Concrete Specimen with Compressometer Attached ???????.148 
Figure 5.15     Humboldt Length Comparator, Mold, and Concrete Specimen ???.149 
Figure 5.16     Model 164 Test Set and Proove? It Cells ????????????150 
 
Figure 6.1       Slump Flow vs. Concrete Age for Phase I ???????????..153 
 
Figure 6.2       Slump Flow vs. Concrete Age for Phase II ???????????155 
Figure 6.3       Penetration Resistance vs. Concrete Age for Phase II ???????156 
xv xv
 
Figure 6.4       Slump Flow vs. Concrete Age for Phase III ??????????...158 
 
Figure 6.5       Workability of ODSC Mixture (approximately 8.25 inches) ????.161 
 
Figure 6.6       Workability of SCC Mixture (approximately 20 inch slump flow) ?...161 
 
Figure 6.7       Slump vs. Concrete Age ??????????????????.163 
 
Figure 6.8       Slump Flow vs. Concrete Age ????????????????164 
 
Figure 6.9       Slump vs. Concrete Age for all Concrete Mixtures ????????164 
 
Figure 6.10     Penetration Resistance vs. Concrete Age ???????????...165 
 
Figure 6.11    Compressive Strength vs. Concrete Age for Phase IV ???????171 
 
Figure 6.12    Modulus of Elasticity vs. Concrete Age for Phase IV ???????.173 
Figure 6.13     Predicted vs. Measured Elastic Modulus according to ACI 318 (2002)   
                         Equation for Phase IV ???????????????????174 
 
Figure 6.14     Predicted vs. Measured Elastic Modulus According to ACI 363 (2002)   
                         Equation for Phase IV ????????????????.??...174 
 
Figure 6.15     Drying Shrinkage vs. Concrete Age ?????????????...176 
Figure 6.16     91-Day Permeability Results ????????????????..179 
 
Figure 6.17    365-Day Permeability Results ????????????????.179 
 
Figure 6.18    Attaining Raw Materials from Stock Piles ???????????..182 
Figure 6.19    Unloading Raw Materials onto Conveyer Belt ??????????183 
Figure 6.20    Raw Materials being Delivered to Hopper via Conveyer Belt ????183 
Figure 6.21    Raw Materials being Mixed by Ready Mix Truck ????????..184 
Figure 6.22    Slump Flow vs. Mixing Time under Laboratory and Field Conditions ..186 
Figure 6.23    Temperature Profile Obtained from I-Button ???.???????.188 
 
Figure 6.24    Penetration Resistance vs. Concrete Age under Laboratory and Field  
                        Conditions ???????????????????????...188 
 
xvi xvi
Figure 6.25    Compressive Strength vs. Concrete Age under Laboratory and Field  
                        Conditions  ??????????????????????..?189 
 
Figure 6.26    Modulus of Elasticity vs. Concrete Age under Laboratory and Field  
                        Conditions ?????...?????????????????....190 
 
Figure 6.27    Compressive Strength vs. Concrete Age for VMA Mixtures????...201 
 
Figure 6.28    Modulus of Elasticity vs. Concrete Age for VMA Mixtures ???.?.201 
 
Figure 6.29    Compressive Strength vs. Concrete Age for Fly Ash Mixtures???...202 
 
Figure 6.30     Modulus of Elasticity vs. Concrete Age for Fly Ash Mixtures??.?..202 
 
Figure 6.31    Compressive Strength vs. Concrete Age for Silica Fume Mixtures ?....203 
. 
Figure 6.32     Modulus of Elasticity vs. Concrete Age for Silica Fume Mixtures?.?203 
 
Figure 6.33    Compressive Strength vs. Concrete Age for GGBFS Mixtures ???..204 
 
Figure 6.34     Modulus of Elasticity vs. Concrete Age for GGBFS Mixtures ???..204 
 
Figure 6.35     Compressive Strength vs. Concrete Age for Micron 3 Mixtures???205 
 
Figure 6.36     Modulus of Elasticity vs. Concrete Age for Micron 3 Mixtures ???205 
 
Figure 6.37     Compressive Strength vs. Concrete Age for Limestone Mixtures ??.206 
 
Figure 6.38     Modulus of Elasticity vs. Concrete Age for Limestone Mixtures ??..206 
 
 
Figure 6.39    Predicted vs. Measured Elastic Modulus According to ACI 318 (2002)   
                       Equation for Phase V ??????????????????......207 
 
Figure 6.40    Predicted vs. Measured Elastic Modulus According to ACI 363 (2002)  
                       Equation  for Phase V ??????????????????.?.207 
 
Figure 6.41    Graphical Results of the Effect of VMA on Fresh Concrete Properties .210 
 
Figure 7.1      Proposed Field Site ????????????????????.215 
 
 
 
 
 
xvii xvii
 
 
 
 
CHAPTER 1 
 
INTRODUCTION 
 
1.1 STATEMENT OF PROBLEM 
In recent years, drilled shaft concrete mixtures are facing increasing demands for 
fluidity.  One of the primary reasons for this increased need for fluidity is the utilization 
of larger diameter shafts, deeper shafts, and congested rebar cages.  The use of larger 
diameter shafts that are designed for large bending moments and seismic conditions 
require high amounts of reinforcement to be placed within the shaft.  Consequently, the 
rebar cages have become progressively more congested and resistive to concrete flow.  
The addition of numerous access tubes for integrity testing has also lead to increased 
congestion in the rebar cages.  These heavily congested rebar cages have lead to 
increased blockage due to the contact within the aggregates when the concrete is forced 
through the rebar cage.  Even when a concrete mixture has sufficient workability, 
blockage could occur due to the bridging of the coarse aggregate at the vicinity of the 
reinforcement bars.  In addition, tremie placement of drilled shaft concrete may require 
prolonged periods for concrete placement, which may result in a loss of concrete 
workability before the shaft is completed.  It has been observed by experienced engineers 
that this loss of workability has lead to structural defects due to the entrapment of debris 
within the shaft.  These large diameter and deep shafts also call for large amounts of 
concrete to be placed.  Case studies have shown that with these massive concrete pours 
 1
large amounts of bleed water can be generated and begins to rise up in the column.  The 
rising bleed water can result in larger interfacial transition zones, loss of bond between 
the reinforcement and concrete, surface streaking, and vertical bleed channels in the 
interior of the shaft.   
 Many state DOT specifications have not kept appropriate workability 
considerations as a special aspect of drilled shaft concrete to meet these increasing 
demands for fluidity.  For this reason, other viable materials such as self-consolidating 
concrete (SCC) could be possible solutions for this increased need for fluidity.  Although 
the use of SCC has been largely implemented in the precast/prestressed industry, the 
potential benefits in drilled shaft construction are enormous.  SCC has the potential to 
address many of the problems associated with drilled shaft construction because of the 
inherent workability, passing ability, resistance to segregation, and reduced bleeding of 
this type of concrete.  The general requirements for SCC mixtures are as follows: 
? Reduced volume of coarse aggregate: as the size and amount of coarse aggregate 
plays an important role on the passing ability of the concrete mixture. 
? Increased volume of paste: the friction between the aggregate controls the 
spreading and the filling ability of the concrete. 
? Increased volume of very fine material: this ensures sufficient workability while 
reducing the risk of segregation and bleeding. 
? High dosage of high-range water reducing admixtures: these provide the 
necessary fluidity. 
? Viscosity modifying admixture (VMA): these admixtures can potentially reduce 
bleeding and coarse aggregate segregation.  
 2
SCC has not currently been used for drilled shaft construction in North America.  Some 
of the potential impediments include the general and overall lack of experience and 
research with these concrete mixtures for drilled shaft construction.  As a result, 
extensive research must be conducted to generate interest in the construction community 
and to develop DOT acceptance of the use of SCC in drilled shaft construction, especially 
when inspection is difficult.   
 
1.2 RESEARCH OBJECTIVES 
 The primary objectives of this research are to evaluate the use of SCC in drilled 
shaft construction, identify appropriate testing techniques and characteristics for this 
specific application, and potential problems or concerns with the use of SCC in drilled 
shaft construction.  A laboratory testing program as well as a later full-scale field study 
will examine the difference between ordinary drilled shaft concrete and SCC for both 
fresh and hardened properties.  The fresh properties include filling ability, passing ability, 
segregation resistance, workability over time, bleeding characteristics, and controlled 
setting, while the hardened properties include the comparison of the compressive 
strength, elastic modulus, drying shrinkage, and permeability.  It is anticipated that this 
research will lead to additional interest in this topic from state and national transportation 
agencies.  While there is considerable research being directed toward SCC as a material, 
this research will be primarily focused upon the application of this technology to the 
drilled shaft industry.  
 
 
 3
1.3 RESEARCH SCOPE 
 This research project was subject to a literature review of published material 
related to SCC.  Chapter 2 of this thesis contains information regarding the factors that 
influence both the fresh and hardened concrete properties of SCC.  These fresh properties 
primarily consist of the filling ability, passing ability, and segregation resistance, while 
the hardened concrete properties include compressive strength, modulus of elasticity, 
drying shrinkage, and permeability.  Chapter 3 will address several aspects of design and 
construction that are essential for high-quality drilled shaft concrete and problems that are 
encountered in drilled shaft construction that leads to poor quality drilled shaft 
foundations.  Selected examples of more common problems associated with drilled shaft 
concrete are cited in this chapter so that these problems can be understood.   
 Chapters 4 and 5 present the laboratory testing program, raw materials, and 
testing procedures for both fresh and hardened concrete properties utilized for this 
research project.  Chapter 6 provides an in-depth discussion and analysis of the laboratory 
testing program as well as providing for a comparison between ordinary drilled shaft 
concrete and SCC for fresh and hardened concrete properties. 
 Chapter 7 presents a proposed field study to be conducted in South Carolina.  This 
proposed field study will examine the difference between ordinary drilled shaft concrete 
and SCC for both fresh and hardened properties under simulated field conditions.  
Finally, Chapter 8 offers conclusions and recommendations based on the results and 
analysis provided in Chapter 6.   
  
 4
 
 
 
 
CHAPTER 2 
 
LITERATURE REVIEW OF SELF-CONSOLIDATING CONCRETE 
 
A review of literature pertaining to relevant research topics associated with self-
consolidating concrete (SCC) is presented in this chapter.  The topics covered include a 
background of SCC, SCC testing procedures, fresh concrete properties of SCC, and 
hardened concrete properties of SCC. 
2.1 INTRODUCTION    
In the early 1980s, durability issues related to concrete structures were a major 
concern and topic of interest in Japan.  The gradual reduction in high-quality construction 
practice and concrete placement by unskilled labor resulted in deficient concrete 
structures (Okamura and Ouchi 1999).  In an effort to produce durable concrete structures 
independent of the quality of construction practice, Professor Hajime Okamura at the 
University of Tokyo developed self-consolidating concrete that would be able to 
consolidate under its own weight without the need for external vibration.   
 Self-consolidating concrete is able to fill formwork, encapsulate reinforcement 
bars, and consolidate under its own weight.  At the same time it is cohesive enough to 
maintain its homogeneity without segregation or bleeding.  This makes SCC useful in 
applications where placing concrete is difficult, such as heavily-reinforced concrete 
structures or where formwork is complex.  Rilem Report 23 from Technical Committee 
174-SCC (Skarendahl 2000) suggests that three main functional requirements of SCC are 
as follows: 
 5
1. Filling Ability: The ability of the concrete to completely fill formwork and 
encapsulate reinforcement without the use of external vibration. 
2. Passing Ability: The ability of the concrete to pass through restrictive sections of 
formwork and tightly spaced reinforcement bars without blockage due to 
interlocking of aggregate.  
3. Segregation Resistance: The ability of the concrete to keep particles in a 
homogenous suspension throughout mixing, transportation, and placement. 
 
The objective with the development of SCC is to overcome problems associated 
with conventional concrete that include improper consolidation, inability to pass and 
encapsulate reinforcement bars, and the incapability to adequately fill formwork.  
However, the acceptance and application of SCC in North America requires an orderly 
and conscious approach because suppliers, contractors, engineers, and architects are 
concerned with different aspects of the concrete?s performance (Khayat and Daczko 
2003).  In addition, this approach is imperative because SCC is being developed by 
multiple agencies with different approaches, and there is a lack of standardized tests to 
assess the quality of SCC.  This has led well-known organizations, such as ASTM and 
RILEM, to address this issue and develop standardized testing procedures.  
 As standardized tests and well-defined mixture proportioning become available, 
the familiarity and use among suppliers, contractors, engineers, and architects will 
increase with confidence allowing the user to quantify the benefits of SCC.  Some of 
these benefits include reduced labor cost, superior finish, reduced need for surface 
patching, no vibration, and reduction in noise pollution.   
 6
2.2 SCC TESTING PROCEDURES  
The Filling Ability, Passing Ability, and Segregation Resistance of a SCC 
mixture must be evaluated through appropriate test methods to determine its quality.  
These properties are not independent from each other, but interrelated in some aspect.  
For example, the deformation capacity or filling ability is in part related to the viscosity, 
where the viscosity is strongly related to the segregation resistance.  For that reason, 
some of the tests developed for SCC evaluate one or more of the fresh properties.  
Numerous tests have been developed for the evaluation of the fresh properties of SCC; 
however, a review of test methods that are relevant to this research and drilled shaft 
applications is presented in this section.  The tests covered include the slump flow test, L-
Box, J-Ring, and segregation column.  The information presented in this section is 
offered only as a guide until standardized tests are developed for SCC testing.  
 
2.2.1 Slump Flow Test 
The assessment of SCC to flow involves the evaluation of the filling ability or 
deformation capacity.  The slump flow test is one of the most common and popular test to 
evaluate the deformation capacity of SCC because the procedure and apparatus are 
relatively simple (Takada and Tangtermsirikul 2000).  The slump flow test is used to 
assess the filling ability of SCC in the absence of obstructions.  The rate of deformability 
can be assessed by determining the T
50
 time while the segregation resistance can to a 
certain degree be visually inspected.  The T
50 
time corresponds to the time that it takes for 
the concrete to flow 20 inches during the slump flow test. 
The slump flow test consists of filling an ordinary slump cone with SCC without 
any rodding.  The cone is then lifted and the mean diameter is measured after the 
 7
concrete has ceased flowing.  The apparatus for the slump flow test can be seen in Figure 
2.1.  The PCI (2003) states that it can be argued that because the slump flow test only 
assesses the free flow, unrestricted by boundaries, it is not representative of what happens 
in concrete construction.  However, the slump flow test is useful in evaluating the 
consistency of SCC as delivered to the job site, and it gives some indication of 
segregation resistance by visual observation (PCI 2003). 
The slump flow test can be performed in the upright or inverted position, and the 
method utilized should be used consistently without switching from one to the other.  The 
upright and inverted methods can be seen in Figures 2.1 and 2.2, respectively.  The 
inverted method allows the slump cone to be easily filled by pouring the sample into a 
larger opening, which reduces the amount of spillage.  Furthermore, the inverted method 
does not require a person to stand on the slump flow table because the weight of the 
concrete holds the cone downward onto the table.  Ramsburg (2003) reports that it is 
possible that only one technician can conduct the slump flow by either method, though 
most users state that two technicians are needed for the upright position.  However, one 
may argue that the two methods will produce different slump flow values.  A recent study 
conducted by Oldcastle Inc. evaluated the difference in slump flow values between the 
two methods using three different mix designs with three different levels of performance 
(Ramsburg 2003).  The three different levels of performance were slump flows less than 
25 inches, slump flows over 25 inches, and slump flows over 25 inches with noted 
segregation and bleeding.  The results indicate that there is only a minimal difference in 
the slump flow between the two methods. 
 
 8
 
 
     
        
 
 
 
 
 
               Figure 2.1 ? Upright Slump Cone Method (PCI 2003) 
 
 
 
 
 
 
 
 
 
 
 
 
               Figure 2.2 ? Inverted Slump Cone Method (PCI 2003) 
 9
As previously reported, the T
50 
time corresponds to the time that it takes for the 
concrete to flow 20 inches during the slump flow test.  The T
50
 time is often used to 
evaluate the viscosity or rate of deformability of SCC.  However, Takada and 
Tangtermsirikul (2000) reported that the T
50
 time is not a direct measure of the viscosity 
of the mix independent of the slump flow value.  For instance, a larger slump flow value 
will produce a lower T
50
 time when the viscosity of the mix is constant.  The T
50
 time can 
be used to evaluate the difference in viscosity of mixtures only when the slump flow 
value is constant (Takada and Tangtermsirikul 2000).  Additionally, the T
50 
time can be 
used as an indication of production uniformity of a given SCC mixture.  The PCI (2003) 
states that the T
50
 time should not be used as a factor to reject a batch of SCC, but rather 
as a quality control test.  However, recent provisions provided by the FDOT state that the 
T
50
 time should be between 2 and 7 seconds for acceptance purposes (Mujtaba 2004).  
 Ramsburg (2003) reports that the T
50 
times are somewhat arbitrary due to the 
difficulty of starting and stopping a clock while conducting the slump flow test.  This 
issue is more of a concern as the T
50
 times become lower, where the possible intervals are 
less than 1.5 seconds.  Furthermore, the tests conducted by Oldcastle Inc. show an 
increase in T
50
 times when performing the inverted slump flow test (Ramsburg 2003).  It 
was further determined that as the slump values increased, the difference in T
50
 times 
were found to be less obvious between the two methods.  Moreover, the inverted method 
could possibly improve the accuracy of the T
50
 times when the intervals are only a few 
seconds; thus, a small difference in viscosity could be more noticeable with the inverted 
method (Ramsburg 2003).   
 10
One of the most critical requirements for SCC is that it must not segregate during 
or after placement.  The slump flow test provides an indication of the segregation 
resistance by visual observation.  Therefore, the visual stability index (VSI) was 
developed to determine the ability of a SCC mixture to resist segregation.  The VSI 
procedure is to assign a numerical rating from 0 to 3, in increments of 0.5, based on the 
homogeneity of the mixture after the slump flow test has been conducted.  To 
differentiate the textural properties of SCC, it should be ranked according to Table 2.1 
and Figure 2.3.  
The basis for the VSI is that when the segregation resistance is not sufficient, the 
coarse aggregate will tend to stay in the center of the slump flow patty and mortar at the 
SCC border (Takada and Tangtermsirikul 2000, and PCI 2003).  In the case of minor 
segregation, a border of mortar without coarse aggregate can occur at the edge of the 
slump flow patty (PCI 2003).  Since the slump flow patty has no significant depth 
through which settlement of aggregate can occur, the visual inspection of SCC in the 
wheelbarrow or mixer should be part of the process in determining the VSI rating (PCI 
2003).  In fact, Bonen and Shah (2004) state that visual evaluation of segregation from 
the slump flow patty is an inadequate measure for predicting segregation resistance in the 
static state.  Khayat et al. (2004) reports that the VSI rating of the slump flow patty is 
considered part of the dynamic stability given the fact the concrete can exhibit some non-
uniform texture following some mixing and transport; whereas, the VSI can be 
considered as a static stability index when it is observed in the wheelbarrow or mixer 
following some period of rest time.   
 
 11
 
         Table 2.1 ? Visual Stability Index (VSI) Rating (Khayat et al. 2004) 
Rating Criteria 
0 No evidence of segregation in slump flow patty, mixer drum, 
or wheelbarrow 
1 No mortar halo in slump flow patty, but some slight bleeding on 
surface of concrete in mixer drum and/or wheelbarrow 
2 
Slight mortar halo (<10mm) in slump flow patty and noticeable 
layer of mortar on surface of testing concrete in mixer drum and 
wheelbarrow 
3 
Clearly segregating by evidence of large mortar halo (>10mm) 
and thick layer of mortar and/or bleed water on surface of testing
concrete in mixer drum or wheelbarrow 
 
 
 
 
 
    Figure 2.3 - Visual Stability Index Rating (Degussa Construction Chemicals 2004) 
 
 12
2.2.2 L- Box Test 
The L-Box is used to assess the passing ability of a SCC mixture.  This test is 
suitable for laboratory and perhaps for site purposes (PCI 2003).  The apparatus consist 
of a rectangular-section box in shape of an ?L? with a vertical and horizontal section 
separated by a removable gate as shown in Figure 2.4.  The L-Box is equipped with 
reinforcement bars separated by narrow openings that are designed to evaluate the 
passing ability of a SCC mixture.  The reinforcement bars can be different diameters and 
spaced at different intervals (PCI 2003).  The PCI (2003) suggests that three times the 
maximum aggregate size may be appropriate for the reinforcement spacing. 
The L-Box test is conducted by filling the vertical section of the L-Box with SCC, 
and then the removable gate is lifted to allow the SCC to flow into the horizontal section 
(PCI 2003).  After the flow has ceased, the height of the SCC at the end of the horizontal 
section (H
2
) and the remaining SCC in the vertical section (H
1
) is measured and 
expressed as a blocking ratio.  This blocking ratio (H
2
/H
1
) is an indication of the passing 
ability of a SCC mixture.  The closer the blocking ratio is to 1, the better the passing 
ability of the SCC mixture.  Petersson (2000) reports that according to Swedish 
experience, a blocking ratio of 0.80- 0.85 is an acceptable range of values.   
 
 13
 
Figure 2.4 ? L-Box Testing Apparatus (PCI 2003) 
 
2.2.3 J-Ring Test  
The J-Ring test is used to determine the passing ability of a SCC mixture.  This 
test is suitable for laboratory and perhaps for site purposes (PCI 2003).  The equipment 
consists of an open steel circular ring, drilled vertically to accept sections of 
reinforcement bars as shown in Figure 2.5.  The rods can be different diameters and 
spaced at different intervals (PCI 2003).  The PCI (2003) suggests that three times the 
maximum size aggregate may be appropriate for the reinforcement spacing.  The spacing 
of the rods at different intervals will impose a more or less severe test of the passing 
ability depending on the application.   
The J-Ring test is used in conjunction with the slump flow test.  The combination 
of the two tests will allow the assessment of the passing ability of the SCC mix design.  
 14
This test is performed in the same manner as the slump flow test with the addition of the 
J-Ring.  The difference between the slump flow and the J-Ring flow is compared, and 
then a passing ability rating is assigned according to Table 2.2.  The larger the difference 
between the slump flow and the J-Ring flow indicates less passing ability.  Recent 
provisions provided by the FDOT state that the difference between the slump flow and 
the J-Ring flow should be no more than 2 inches (Mujtaba 2004).  
 
       Table 2.2 - J-Ring Passing Ability Rating (ASTM J-Ring Draft 2004) 
Difference between
Slump Flow  
 and J-Ring Flow 
Passing Ability
Rating 
Remarks 
0 ? X ? 1 inch 0 No visible blocking 
1 < X ? 2 inches 1 Minimal to noticeable blocking
X > 2 inches 2 Noticeable to extreme blocking
 
 
 
 
 
 
 
 
 
 
Figure 2.5 - J-Ring Testing Apparatus (ASTM J-Ring Draft 2004) 
 15
2.2.4 Segregation Column Test 
 The segregation column test is used to determine the stability and segregation 
resistance of a SCC mixture.  This test can be used for both laboratory and perhaps site 
purposes (ASTM Segregation Column Draft 2004).  The equipment consists of an 8-inch 
diameter by 26-inch tall schedule 40 PVC pipe.  The PVC pipe is separated into 4 equal 
sections each measuring 6.5-inches in height.  A collector plate measuring 20-in. x 20-in. 
is used to collect the concrete from the different sections of the column.  The segregation 
column and the collector plate can be seen in Figure 2.6.   
The segregation column test is conducted by placing a sample of concrete in the 
cylinder mold in one lift without any means of mechanical vibration.  After the concrete 
is allowed to sit for 15 minutes, the concrete column is separated into four equal sections 
using the collector plate.  The concrete from the top and bottom section is wet-washed 
through a No. 4 sieve leaving the coarse aggregate on the sieve.  The mass of aggregate 
from these sections of the column is obtained, and a segregation index is determined 
using Equation 2.1.  
                                               
MB
TB
CA
CACA
SI
)( ?
=                                            Eq. 2.1 
In Equation 2.1, SI is the segregation index, CA
T
 is the mass of coarse aggregate in the 
top section, CA
B
 is the mass of coarse aggregate in the bottom section, and CA
BM
 is the 
mass coarse aggregate per section of the column according to Equation 2.2. 
                                     [ ]
MMBM
CACACA ??= 0052.0007.0                              Eq. 2.2 
In Equation 2.2, CA
M
 is the mass of coarse aggregate in 1 yd
3 
of concrete.   
 16
 
 
Figure 2.6 - Segregation Column Testing Apparatus (ASTM Segregation Column    
                    Draft 2004) 
 
 
 17
2.3 FRESH CONCRETE PROPERTIES 
SCC is characterized by its filling ability, passing ability, and segregation 
resistance.  SCC has to have a low yield stress value to ensure high flowability, small 
aggregate particles to prevent blockage, and adequate viscosity to prevent segregation.  
Thus, these characteristics must be discussed in further detail to allow the user to develop 
a well-designed SCC mixture.  
2.3.1 Rheology   
 Before discussing the various ways to modify SCC characteristics, it is helpful to 
discuss a few basic principles of rheology.  Rheology can be described as the study of 
deformation and flow of matter under stress (Mindess et al. 2003).  Understanding and 
knowledge of rheology behavior has been essential in the development of self-
consolidating concrete and influences the performance of the fresh concrete properties.  
The rheology of concrete, paste, or mortar may be characterized by its yield stress and 
plastic viscosity.  The rheology of fresh concrete, including self-consolidating concrete, is 
most often defined by the Bingham Fluid Model using Equation 2.3 (Mindess et al. 
2003).  
                                                ???? *+= o                                                       Eq. 2.3 
In Equation 2.3, ? is the shear stress in psi, ?
o
  is the yield stress in psi, ? is the plastic 
viscosity in psi 
.
 seconds, and ? is the shear strain in 1/seconds.  Figure 2.7 shows that the 
Bingham Fluid Model requires a yield stress to obtain a strain that is followed by 
increasing shear stress with increasing shear strain (Khayat and Tangtermsirikul 2000).  
Khayat and Tangtermsirikul (2000) report that the target rheological properties for SCC 
are a low yield stress value together with an adequate plastic viscosity.  
 18
 
 
 
 
 
 
 
 
                                                Figure 2.7 - Bingham Fluid Model 
A number of rheometers, e.g. BML viscometer and BTRHEOM rheometer, have 
been developed to measure the true rheological properties of fresh concrete.  Rheometers 
provide two parameters, namely the initial yield stress value and the plastic viscosity, to 
characterize the fresh properties.  These rheometers are useful in evaluating what the 
effects of different materials, such as cements, fillers, aggregates, mineral admixtures, 
and chemical admixtures have on the yield stress and plastic viscosity.  According to 
Emborg (1999), rheometers are considered to be the most accurate way to describe the 
real behavior of fresh concrete.  However, rheometers are based on different principles, 
and the results from different rheometers can not be easily compared.  While it is likely 
that the use of rheology tests and rheometers will increase in the future, rheometers are 
expensive to purchase and existing tests are primarily used for initial mixture 
proportioning, testing, and research efforts.  
 
 
 19
2.3.2 Filling Ability  
 Self-consolidating concrete must be able to fill formwork and encapsulate 
reinforcement without the use of external vibration.  The high deformation capacity of 
SCC is related to the yield stress; thus, the yield stress must be reduced in order to ensure 
that SCC can flow around obstacles and achieve good filling ability.  The deformation 
capacity can be increased by the reduction of interparticle friction between the solid 
particles, which include the paste, coarse aggregate, and fine aggregate (Khayat and 
Tangtermsirikul 2000).  The interparticle friction between the paste particles requires the 
dispersion of fine material by superplasticizers.  Khayat and Tangtermsirikul (2000) state 
that unlike water that reduces both the yield stress and viscosity, superplasticizers reduce 
the yield stress and cause a limited decrease in viscosity.  As a result, the addition of 
superplasticizers can provide highly flowable concrete without a significant reduction in 
cohesiveness.  In order to reduce interparticle friction due to aggregate-aggregate contact, 
Khayat and Tangtermsirikul (2000) recommend that the interparticle distance between 
the aggregate be increased.  This is achieved by reducing the total aggregate content and 
increasing the paste content.  Thus, the following actions should be taken to achieve 
adequate filling ability (Khayat and Tangtermsirikul 2000):  
1. Increase the deformability of the paste 
? Balanced water-to-cementitious materials ratio (Balanced so that 
adequate deformability and deformation velocity can be achieved) 
? Superplasticizers 
 
2. Reduced interparticle friction 
? Low coarse aggregate volume 
? Higher paste contents 
 
 
 20
 Although different superplasticizers are available in the market today, almost all 
new and innovative superplasticizers are polycarboxylate based mixtures (Bonen and 
Shah 2004).  It must be noted that the following discussion is based on the work of Bury 
and Christensen (2003).  These polycarboxylate based superplasticizers are characterized 
by their strong dispersing action, controlled slump retention, enhanced concrete stability, 
enhanced pumping ability, and enhanced finishing ability.  These superplasticizers 
function by imparting a negative charge on the cement particles that cause them to repel 
from one another.  Traditional superplasticizers also function in this manner, but the new 
polycarboxylate based superplasticizers have side chains with varying lengths that aid in 
keeping the cement particles apart allowing water to surround more surface area of the 
cement particle (steric hindrance).   
The effectiveness of superplasticizers last only as long as there is sufficient 
molecules available to cover the surface area of the cement particles.  Therefore, it is 
likely that with time and prolonged mixing the effectiveness of the superplasticizers will 
become inadequate and the workability of the mix will be lost.  Repeated addition of 
superplasticizers may be beneficial from the standpoint of workability; however, it may 
increase bleeding, segregation, and change the amount of entrained air (Neville 1996).  
Neville (1996) goes on to suggest that the workability regained from the re-dosage may 
decrease at a faster rate.  Therefore, the re-dosage should be applied immediately prior to 
placement according to the recommendations of the admixture supplier. 
Bonen and Shah (2004) state that the use of fine material, such as silica fume, will 
increase the yield stress because of greater water absorbance.  Thus, it would be expected 
that the superplasticizer dosage should be increased to obtain the same slump flow.  
 21
Ferraris et al. (2001) reported that with a constant amount of water and cementitious 
material, the addition of 8% and 12% silica fume increased the superplasticizer dosage by 
30% and 50% over the control mix.  In fact, it is usually reported that if the volume 
concentration of solids is held constant, the addition of a fine material will decrease the 
workability (Ferraris et al. 2001).  The most common reason for this reduction in 
workability is due to increased surface area of the fine material, which will increase the 
superplasticizer demand for the same water content.  However, it is reported in some 
cases that the addition of fine material can decrease the water demand.  Ferraris et al. 
(2001) states that the reduction of water demand for fine material, especially fly ash, is 
due to spherical particles that easily move past each other reducing the interparticle 
friction.   
The aggregate shape also influences the filling ability to a certain degree.  It is 
reported that flat and elongated particles will lead to a decrease in the workability 
(Hodgson 2003).  This is due to the fact that angular aggregate will have more 
mechanical interlocking and will need more work to overcome interparticle friction.  For 
example, Petersson (1999) states that when crushed sand is used, the fluidity is decreased 
for the same amount of superplasticizer.  Conversely, rounded aggregates will act like 
?ball bearings? allowing the particles to easily move past each other, which will increase 
the workability for a constant paste and water content.  It is generally considered that 
rounded and smaller aggregate particles will increase the filling ability of concrete.   
 
 
 
 22
2.3.3 Passing Ability 
 The level of passing ability of SCC is a function of the stability, coarse aggregate 
content, coarse aggregate size, and reinforcement spacing.  SCC with excellent 
deformability but with insufficient cohesiveness will lead to local aggregate segregation 
between the paste and coarse aggregate at the vicinity of the reinforcement that could 
lead to severe blockage (Khayat et al. 2004).  This will not only lead to decreased passing 
ability, but it will also lead to an increase in the concentration of coarse aggregate at the 
reinforcement.  The passing ability is also affected when the coarse aggregate size is 
large and/or the coarse aggregate content is high.  This mechanism of blocking can be 
explained by the two dimensional model shown in Figure 2.8 (Khayat and 
Tangtermsirikul 2000).  Figure 2.8 illustrates that the aggregate particles around an 
opening must change their path of travel to properly pass through the reinforcement.  As 
a result, aggregate particles may collide at the reinforcement opening.  This aggregate 
interaction may cause the aggregate to form a stable arch at the vicinity of the 
reinforcement opening (Khayat and Tangtermsirikul 2000).  Therefore, to achieve 
suitable passing ability the following steps should be considered (Khayat and 
Tangtermsirikul 2000):  
1. Enhance the cohesiveness to reduce segregation of aggregate 
? Low water-to-cementitious materials ratio 
? Viscosity modifying admixture 
 
2. Compatible clear spacing and aggregate characteristics 
? Low coarse aggregate contents 
? Smaller maximum aggregate size 
 
 
 23
 
 
Figure 2.8 - Mechanism of Blocking (Khayat and Tangtermsirikul 2000) 
 
 
 
  Khayat et al. (2004) conducted studies on the passing ability by evaluating the 
dynamic stability of SCC using the L-Box and J-Ring apparatus.  It was reported that 
SCC mixtures prepared with 843 lb/yd
3
 of cement with relatively low viscosity exhibited 
greater passing ability than SCC mixtures prepared with 650 lb/yd
3
 of cement.  Khayat et 
al. (2004) reported that the concrete mixtures prepared with 650 lb/yd
3
 contained more 
coarse aggregate that increased the risk of collision and interaction among solid particles, 
which lead to a reduced ability to flow between the reinforcement bars.  The greater 
tendency of aggregate blockage resulted in lower passing ability in both the J-Ring and 
L-Box tests.  Studies conducted by Kim et al. (1998) also indicate that the passing ability 
was increased with decreasing coarse aggregate content.  The results further indicate that 
SCC mixtures prepared with volume ratios of coarse aggregate-to-concrete of 0.27 and 
0.31 demonstrated a higher passing ability than volume ratios of 0.35 and 0.39 at a 
constant water-to-binder ratio.  
 Studies conducted at the Swedish Cement and Concrete Institute investigated the 
blocking in the L-Box apparatus using different maximum size aggregates and 
reinforcement spacing (Petersson 1999).  The paste content in the mixes remained 
constant with slump flow values ranging from 25.5 to 28.5 inches.  The results in Figure 
 24
2.9 indicate that as the reinforcement spacing increases relative to the maximum 
aggregate size the passing ability is also increased.  Furthermore, closer examination of 
Figure 2.9 reveals that for the same reinforcement spacing the use of smaller aggregates 
produced higher blocking ratios.  Thus, it can be concluded that the maximum size 
aggregate and reinforcement spacing has an effect on the passing ability of SCC.    
 
 
Figure 2.9 - Blocking Ratios versus Reinforcement Spacing for Different Size 
                     Aggregate (Petersson 1999) 
 
2.3.4 Segregation Resistance  
 One of the most important requirements of SCC is that it must not segregate 
during or after placement.  SCC is much more prone to segregation than normal concrete 
due to the sharp reduction in viscosity caused by the high dosages of superplasticizers.  
Thus, it is essential that SCC have a high resistance to segregation so that there is 
 25
homogenous distribution of materials in the hardened concrete.  Khayat and 
Tangtermsirikul (2000) report that SCC should not show signs of segregation in static or 
dynamic conditions, which include bleeding of water, paste and aggregate segregation, 
and non-uniformity in air pore size distribution.  Thus, the following steps should be 
considered to produce sufficient segregation resistance (Khayat and Tangtermsirikul 
2000): 
1. Reduce the segregation of solid particles 
? Reduced maximum size aggregate  
? Low water-to-cementitious materials ratio 
? Viscosity modifying admixture 
2. Minimize bleeding due to free water 
? Low water content 
? Low water-to-cementitious materials ratio 
? Powders with high surface area 
? Viscosity modifying admixture 
 
Segregation of aggregate is related to a number of variables that consist of the 
particle size, particle specific gravity, and the proportions of the mixture.  Bonen and 
Shah (2004) report that the use of larger coarse aggregates will settle much faster than 
smaller coarse aggregates when the density and viscosity of the suspension is held 
constant.  Additionally, gradation is also an important factor in determining the proper 
coarse aggregate, especially where reinforcement is highly congested and/or the 
formwork has small dimensions.  Hodgson (2003) reports that a gap-graded coarse 
aggregate promotes a greater degree of segregation than well-graded coarse aggregate.  
Thus, the coarse aggregate chosen for SCC is typically round in shape, well-graded, and 
smaller in maximum size than that used for conventional concrete.   
 26
Another method to increase the segregation resistance besides reduction in 
aggregate size is to increase the cohesiveness of the mixture.  This is typically done by 
one of the three methods listed below.  All three methods use superplasticizers to increase 
the fluidity of the mixture, but the difference between them is the method used to prevent 
the segregation (Hodgson 2003).   
1. Powder method 
2. Viscosity modifying admixture method, ?VMA? method 
3. Combination method 
 The powder method utilizes an increase in the volume of fines and low water 
content to reduce the amount of free water.  Free water is defined as water that is not 
adhered to the solid particles and move independently from the solids in a mixture.  
Furthermore, Khayat and Tangtermsirikul (2000) state that it is essential to reduce the 
amount of free water in the mixture because an increase in free water content will 
decrease the viscosity of a SCC mixture.  The most common methods for reducing the 
amount of free water is to use powder materials with a high surface area, use a low water-
to-binder ratio, or both.  For example, for a constant water content, the addition of high 
surface area material can absorb a greater amount of free water compared to cement 
particles. Thus, the plastic viscosity of the mix is increased due to greater water 
absorbance.  Furthermore, the reduction of the water-to-binder ratio will increase the 
phase-to-phase cohesion that will increase the segregation resistance.  Khayat et al. 
(1999) states that fine powder includes cement and supplementary cementitious material 
that is combined to enhance grain-size distribution, packing density, and reduced 
interparticle friction to lower the water demand for a necessary viscosity.   
 27
 The VMA method utilizes lower cement contents, a superplasticizer, and a 
viscosity modifying admixture (VMA).  The addition of a VMA may increase the 
viscosity of a mix to the extent that the water-to-cementitious ratio need not be increased 
(Bonen and Shah 2004).  VMAs can provide adequate stability, reduce bleeding, and 
segregation resistance over a wider range of fluidity.  There are two basic types of VMAs 
that are available in the market, and each VMA is based on the mechanism in which they 
function (Degussa Construction Chemicals 2004): 
1. Thickening Type VMA- This VMA functions by thickening the concrete, 
making it cohesive without significantly affecting the fluidity.  By increasing the 
viscosity of the mixture, the VMA makes the mixture more stable and less prone 
to segregation (Degussa Construction Chemicals 2004).  These are typically 
polyethylene glycol (PEG) based VMAs.   
2. Binding Type VMA- This VMA functions by binding the water within the 
concrete mixture.  This VMA not only increases the viscosity of the mixture, but 
it also reduces bleeding.  The binding type VMA is more potent in modifying the 
viscosity of the mixture than the thickening type (Degussa Construction 
Chemicals 2004).  Welan Gum is an example of this type of VMA.  
Bury and Christensen (2003) state that the use of a VMA also increases the number of 
applications for SCC because more mixtures can be proportioned for a wider range of 
applications.  For example, a VMA can be used with mixtures made with gap-graded 
materials.  In fact, Berke et al. (2003) suggests that when poorly graded material and low 
powder contents are used, the use of a VMA can prove invaluable.  In addition, because 
moisture contents in fine aggregate can change throughout daily operation, the use of a 
 28
VMA has been proven to be very valuable in overcoming deficiencies due to 
uncontrolled moisture (Bury and Christensen 2003).  
The combination approach utilizes a VMA with limited water content.  The VMA 
in this method primarily is used to reduce the variability of the SCC that can arise from 
uncontrolled moisture and placement conditions.  The VMA also controls bleeding and 
renders the concrete more robust, while the low water content provides the necessary 
viscosity (Khayat et al. 1999).   
 
2.4 HARDENED CONCRETE PROPERTIES 
 The hardened properties of concrete are often the most valued by design and 
quality control engineers.  It has become evident that SCC can have a large variation in 
mechanical properties due to the different formulations used.  Despite these variations, 
literature has shown that the mechanical properties of well-designed SCC are comparable 
or better than the corresponding properties of conventional concrete (Bonen and Shah 
2004).  Although many mechanical properties can be evaluated and compared, only the 
mechanical properties that are relevant to this research will be discussed in this section.  
 
2.4.1 Compressive Strength 
 The property that is most often specified for concrete design and quality control is 
the compressive strength.  The testing of the compressive strength is relatively easy to 
perform in the laboratory, and the compressive strength is universally accepted as a 
general index of concrete strength.  There are many determining factors that influence the 
 29
compressive strength of concrete; however, the compressive strength is best described by 
the water-to-cementitious ratio and the porosity relationship.  
When fully compacted, the concrete strength is taken to be inversely proportional 
to the water-to-cementitious ratio.  In 1919, Duff Abrams established the following 
relationship between the water-to-cementitious ratio and the compressive strength 
(Neville 1996).  
                                          
cw
c
K
K
f
/
2
1
=                                                    Eq. 2.4 
In Equation 2.4, f
c
 is the compressive strength, w/c is the water-to-cementitious ratio, and 
K
1
 and K
2
 are empirical constants.  However, at water-to-cementitious ratios less than 
0.38 the maximum possible hydration of the cement is less than 100%.  Therefore, the 
slope of strength gain rate is slowed as the water-to-cementitious ratio is reduced as 
shown in Figure 2.10.   
 
Figure 2.10 - Strength versus Cement-to-Water Ratio (Neville 1996) 
 
 30
The influence of the water-to-cementitious ratio on compressive strength is not 
truly a constitutive law because the water-to-cementitious ratio rule does not include all 
factors that influence the compressive strength (Neville 1996).  Neville (1996) suggests 
that it may be more appropriate to relate the compressive strength of concrete to the 
concentration of solid products of hydration of cement in the space available for these 
products. 
The porosity relationship can be considered one of the most important factors in 
cement based material because it affects both the cement paste matrix and the interfacial 
transition zone (ITZ).  In general, there exist a relationship between the porosity and the 
strength of solids that can be described by Equation 2.5 (Neville 1996). 
                                               ( )
n
cc
pff ?= 1
0,
                                               Eq. 2.5 
In Equation 2.5, f
c
 is the strength of the material, f
c,o
 is the strength at zero porosity, n is a 
coefficient, and p is the porosity.  The coefficient n depends on factors that include the 
cement composition, paste age, and temperature.  This relationship between porosity and 
compressive strength can be seen in Figure 2.11.   
 
 
Figure 2.11 ? Compressive Strength versus Porosity (Neville 1996) 
 31
 
Powers and Brownyard determined that the compressive strength is related to the 
gel-to-space ratio (Mindess et al. 2003).  The gel-to-space ratio is defined as the ratio of 
the gel volume over the summation of the volume of the gel, capillary pores, and air 
voids.  Powers and Brownyard concluded that the compressive strength of the hydrated 
cement is closely related to the following equation: 
                                                                                                          Eq. 2.6 
3
Xaf
c
?=
In equation 2.6, f
c
 is the strength of the material at a given porosity (p), a is the intrinsic 
strength of the material at zero porosity, and x is the gel-to-space ratio.  Where this ratio 
is defined as the summation of the hydrated cement paste to the sum of the volume of the 
hydrated cement and capillary pores.  The relationship between the gel-to-space ratio and 
the compressive strength can be seen in Figure 2.12.  Bonen and Shah (2004) report that 
the compressive strength of SCC is also best approximated by the porosity content.  They 
further suggest that similar to the Powers and Brownyard formulation, the compressive 
strength of SCC is defined in terms of the binder-to-space ratio, b rather than the gel-to-
space ratio, x.  The binder-to-space ratio is defined as the binder volume over the 
summation of the volume of the binder, capillary pores, and air voids.  The binder 
volume is the sum of the gel volume, filler volume, and the solid volume of the 
superplasticizers and VMA.   
 32
 
Figure 2.12 - Strength versus Gel-to-Space Ratio Based on Tested Mortar Cubes 
                      (Neville 1996) 
 In most cases, high contents of fine material are placed within SCC to increase 
segregation resistance.  This addition of fine material can be capable of producing a 
denser microstructure that will decrease both the porosity of the cement paste matrix and 
interfacial transition zone of SCC.  A study conducted at the Swedish Cement and 
Concrete Research Center investigated the microstructure in SCC and conventional 
bridge concretes using image analyzing and light microscopy techniques (Tragardh 
1999).  It was concluded that the porosity of the bulk paste and the ITZ was significantly 
higher in the conventional concrete compared to SCC with the same water-to-
cementitious ratio (Tragardh 1999).  It must be noted that although the SCC and 
conventional concrete had the same water-to-cementitious ratio, the SCC incorporated 
high amounts of fine inert limestone filler that produced a low water-to-binder ratio.  The 
incorporation of fine material in the SCC allowed particles to pack more efficiently 
 33
around the aggregates; therefore, leading to a decrease in porosity around the ITZ.  
Tragardh (1999) further concluded that pores were more evenly distributed between the 
ITZ and bulk paste, and the effect of microbleeding, which leads to an increase of the 
local water-to-cementitious ratio at the interfacial zone, was found to be much less in 
SCC.  It was further determined that the compressive strength for SCC was higher than 
the conventional concrete at the same water-to-cementitious ratio due to this 
improvement in the microstructure (Tragardh 1999).  The results from the compressive 
strength test can be seen in Figure 2.13.  This investigation determined that the 
microstructure properties not only improved in SCC, but shows a strong correlation 
between these microstructure properties and the measured properties (Tragardh 1999).  
 
 
Figure 2.13 ? Average Compressive Strengths of SCC and Conventional Bridge  
                       Concretes with w/c of 0.40 (Tragardh 1999) 
 
  A study conducted at the Master Builders Research and Development Center 
also compared the engineering properties of SCC and conventional concrete (Attiogbe et 
 34
al. 2003).  The study used both conventional concrete and SCC with a cement content of 
640 lb/yd
3
 and 160 lb/yd
3
 of fly ash with a water-to-cementitious ratio of 0.37.  The 
specimens were either steamed or air cured in molds for 24 hours.  Compressive tests 
were then conducted at the ages of 1 and 28 days.  The research indicated that the early-
age porosity was lower in the SCC than the conventional concrete (Attiogbe et al. 2003).  
Attiogbe et al. (2003) reported that the compressive strengths for 1 day and 28 day of the 
steamed-cured SCC were comparable to the steamed-cured conventional concrete.  It was 
further reported that the compressive strength for the air-cured SCC exceeded the 
strengths of the air-cured conventional concrete.  Furthermore, Turcry et al. (2003) 
reported on values that indicate that at similar water-to-cementitious ratios, the 
compressive strength of SCC is comparable or higher than conventional concrete.  The 
results from this study can be seen by looking at Table 2.3.   
 
Table 2.3 - Compressive Strength Results from Turcry et al. (2003) 
SCC 1 OC 1 SCC 2 OC 2
Gravel (lb/yd
3
)
1331 1803 1424 1912
Sand (lb/yd
3
)
1449 1314 1364 1348
Cement (lb/yd
3
)
590 607 590 665
Limestone Filler (lb/yd
3
)
253 0 421 0
Water (lb/yd
3
)
315 286 269 295
Water/Cement Ratio 0.53 0.47 0.46 0.44
Water/Powder Ratio 0.37 0.47 0.27 0.44
Sand/Aggregate Ratio (by mass) 0.52 0.41 0.48 0.41
Compressive Strength (psi) 6960 7400 8700 7251
Modulus of Elasticity (1 x 10
6
 psi)
4.35 5.50 5.20 5.20
 
 OC = Ordinary Concrete 
 35
2.4.2 Modulus of Elasticity  
 For structural design, the modulus of elasticity of concrete increases 
approximately with the square root of its strength.  According to the ACI 318 (2002), the 
modulus of elasticity of concrete can be best approximated by Equation 2.7.   
 
                                       '33
51
c
.
cc
fwE =                                                Eq 2.7 
In Equation 2.7, E
c
 is the modulus of elasticity in psi, w
c
 is the unit weight in lb/ft
3
, and 
f
c
? is the compressive strength in psi.  It is suggested that this formulation is valid for 
density ranging from 90 to 155 pcf and compressive strengths up to 6000 psi.  The ACI 
Committee 363 (2002) ?State-of-the-Art- Report on High Strength Concrete? also found 
that the equation used by ACI 318 (2002) was valid only up to compressive strengths up 
to 6000 psi.  According to the ACI Committee 363 (2002) ?State-of-the-Art- Report on 
High Strength Concrete?, high strength concrete has compressive strengths ranging from 
6,000 to 12,000 psi.  By comparing stress-strain curves for normal and high strength 
concrete, high strength concrete has a more linear and steeper slope in the ascending 
portion of the curve as well as a higher strain at the maximum stress (Jones 2004).  
Therefore, the ACI Committee 363 (2002) recommends the following equation for 
estimating the modulus of elasticity for high strength concrete, which is valid for 
compressive strengths ranging from 3,000 to 12,000 psi.  In Equation 2.8, E
c
 is the 
modulus of elasticity in psi and f
c
? is the compressive strength in psi. 
 
                                   000,000,1'000,40 +=
cc
fE                            Eq. 2.8 
 
 36
In contrast to the compressive strength, the modulus of elasticity of concrete is 
significantly affected by the modulus and volume fraction of the aggregate (Bonen and 
Shah 2004).  Bonen and Shah (2004) report that as the volume fraction of aggregate is 
increased, the modulus of elasticity is increased.  This is an important factor for SCC 
since the aggregate volume fraction is typically lower compared to conventional concrete.  
It is then expected that the elastic modulus of SCC would be lower than conventional 
concrete with the same strength (Bonen and Shah 2004).  In addition to the limited 
aggregate volume fraction, SCC typically incorporates a higher sand-to-aggregate ratio to 
increase its segregation resistance and passing ability.  Therefore, a closer examination 
must be presented to determine how the sand-to-aggregate ratio and aggregate volume 
fraction influence the modulus of elasticity.  
  Su et al. (2002) investigated the effect of the sand-to-aggregate ratio on the 
elastic modulus of SCC.  Their study consisted of varying the sand-to-aggregate ratio of 
SCC from 0.30 to 0.55 while maintaining a constant aggregate volume fraction of 0.6 and 
a water-to-cementitious ratio of 0.39.  By maintaining a constant water-to-cementitious 
ratio and aggregate volume fraction, only the varying sand-to-aggregate ratio should 
influence the elastic modulus.  Su et al. (2002) also invested how the elastic modulus of 
the fine and coarse aggregate influence the modulus of elasticity.  The results from this 
study can be seen by looking at Figure 2.14.  Su et al. (2002) reported that when the 
elastic modulus of the fine aggregate was 2 times that of the coarse aggregate, the elastic 
modulus of concrete increased from 4.05 x 10
6
 psi to 4.3 x 10
6
 psi when the sand-to-
aggregate ratio increased from 30% to 47.5%.  It is further reported that when the elastic 
modulus of the fine aggregate was half of the coarse aggregate, the elastic modulus 
 37
decreased from 3.26 x 10
6 
psi to 3.05 x 10
6
 psi when the sand-to-aggregate ratio increased 
from 30% to 47.5%.  Su et al. (2002) concluded that when the elastic modulus of the fine 
and coarse aggregate are not much different and the total volume fraction of aggregate is 
constant, the elastic modulus of SCC is not significantly affected by the sand-to-
aggregate ratio (Su et al. 2002).   
 
Figure 2.14 - Elastic Modulus versus Sand-to-Aggregate Ratio (Su et al. 2002) 
 
Turcry et al. (2003) further compared the elastic modulus of SCC to conventional 
concrete using two SCC mixtures and two conventional concrete mixtures.  Turcry et al. 
(2003) maintained a sand-to-aggregate ratio of 0.41 for the conventional concrete and 
sand-to-aggregate ratios of 0.52 and 0.48 for the SCC mixtures.  Table 2.3 indicates that 
the conventional concrete had a higher aggregate fraction as well as a lower sand-to-
aggregate ratio.  Turcry et al. (2003) concluded that due to the higher paste volume for 
SCC, the elastic modulus for SCC was lower than conventional concrete at the same 
 38
compressive strengths.  On the other hand, Attiogbe et al. (2003) reported that the 
modulus of elasticity for the SCC mixtures corresponded well with the conventional 
concrete when the strength was held constant.  The study conducted by Attiogbe et al. 
(2003) used the same water-to-cementitious ratio of 0.37 with sand-to-aggregate ratios by 
mass of 0.44 for conventional concrete and 0.53 for the SCC mixtures.  The concrete 
mixtures contained cement and fly ash of 650 lb/ft
3
 and 160 lb/yd
3
, respectively.  
Therefore, both the conventional concrete and SCC has comparable aggregate volume 
fractions with varying sand-to-aggregate ratios (Table 2.3).   
 
2.4.3 Drying Shrinkage 
 Shrinkage is a term that represents the strain caused by the loss of water from 
hardened concrete (Mindess et al. 2003).  Shrinkage of concrete is a function of the paste 
properties, and the response of the paste to moisture loss is modified by several 
parameters.  However, the most important parameter is exerted by the aggregate, which 
will restrain the shrinkage (Neville 1996).  Equation 2.9 states that the ratio of shrinkage 
of concrete, S
c
, to the shrinkage of neat cement, S
p
, depends on the aggregate content, a, 
and the experimental values of n range from 1.2 to 1.7 (Neville 1996).   
                                                                                            Eq. 2.9 
n
pc
aSS )1( ?=
Since SCC incorporates high paste volumes and reduced aggregate content, Equation 2.9 
reveals that SCC is prone to an increase in drying shrinkage compared to conventional 
concrete.  Neville (1996) suggest that for a constant water-to-cementitious ratio, the 
reduction in aggregate content will cause an increase in drying shrinkage.  This 
relationship between water-to-cementitious ratio and aggregate content can be seen in 
Figure 2.15.  
 39
 
Figure 2.15 - Aggregate Content versus Water-to-Cement Ratio (Neville 1996) 
 
Neville (1996) reports that the size and gradation of aggregate per se does not 
influence the magnitude of shrinkage, but the use of larger aggregate permits a leaner mix 
that results in lower shrinkage.  On the other hand, the ACI Committee 209 (2002) 
suggests that the gradation of the aggregate may have an effect on the drying shrinkage.  
According to ACI Committee 209 (2002), for different sand-to-aggregate ratios the 
shrinkage should be modified according to Equation 2.10 and 2.11.  It can be seen from 
Equation 2.10 and 2.11 and Figure 2.16 that as the sand-to-aggregate ratio is increased, 
which indicates more fine aggregate, the shrinkage will also increase.  In Equation 2.10 
and 2.11, ? is the sand-to-aggregate ratio. 
 
 ?014.030.0 +=Shrinkage               %50<?                   Eq. 2.10 
            ?002.09.0 +=Shrinkage                 %50??                    Eq. 2.11  
 40
0.2
0.4
0.6
0.8
1
1.2
0.35 0.4 0.45 0.5 0.55 0.6 0.65
Sand-to-Aggregate Ratio
Shr
i
n
k
a
g
e M
odif
a
ct
i
on Fa
ct
or
                      
Figure 2.16 ? Shrinkage Modification Factor for Different Sand-to-Aggregate Ratios   
                       (ACI Committee 209 2002) 
 
Neville (1996) goes on to report that at constant water contents, the shrinkage is 
decreased with increasing cement content.  In the same manner, at constant cement 
contents, the shrinkage is decreased with decreasing water content.  This is due to the fact 
that as the water-to-cementitious ratio is decreased it is able to better resist shrinkage; 
therefore, the drying shrinkage is decreased as shown in Figure 2.17.  Since SCC 
typically has a lower water-to-cementitious ratio compared to conventional concrete, it 
may be possible that the increase in shrinkage caused by the reduction in aggregate 
content or increase in sand-to-aggregate ratio can, to a certain degree, be compensated by 
the reduction of the water-to-cementitious ratio.  
 41
 
 
Figure 2.17 ? Shrinkage versus Cement Content (Neville 1996) 
 
Kim et al. (1998) studied the drying shrinkage of SCC and conventional concrete 
made with fly ash in which the paste fraction and volume ratio of coarse aggregate-to-
concrete varied.  The basic mixture proportions and experimental results are shown in 
Table 2.4 and Figure 2.18.  Kim et al. (1998) concludes that the experimental results 
show the effects of the water weight and volume ratio of coarse aggregate-to-concrete on 
drying shrinkage.  It was determined that with increasing unit water weight and 
decreasing volume ratio of coarse aggregate-to-concrete, the drying shrinkage was 
increased (Kim et al. 1998).  The reported results from this experiment indicate that the 
drying shrinkage for SCC was 30% to 50% greater than conventional concrete.  Kim et 
al. (1998) concludes that the higher drying shrinkage for the SCC mixtures is due to the 
higher paste volumes, higher water contents, and less coarse aggregate.  Additionally, 
Rols et al. (1999) reported that for their research the drying shrinkage values for SCC 
were 50% higher than conventional concrete containing the same amount of cement.  It 
was determined that the increase in drying shrinkage was due to the increase in the paste 
fraction and decrease in coarse aggregate.   
 42
 
Table 2.4 -  Mixture Proportions (Kim et al. 1998) 
Total W/C Sand/Aggregate
Mix ID Water Cement Fly Ash Fine Coarse Aggregate Ratio Ratio
lb/yd
3
lb/yd
3
lb/yd
3
lb/yd
3
lb/yd
3
ft
3
(By Volume)
SF 1-1 328 657 281 1371 1235 16.1 0.35 0.53
SF 1-2 311 623 267 1317 1381 16.7 0.35 0.49
SF 1-3 295 590 253 1245 1545 17.2 0.35 0.45
SF 1-4 278 556 238 1142 1739 17.8 0.35 0.40
SF 2 320 505 337 1311 1380 16.6 0.38 0.49
NC 2 295 674 0 1305 1744 18.8 0.44 0.43
NC 3 295 843 0 1141 1739 17.8 0.35 0.40
Aggregate
Self-Consolidating Concrete 
Ordinary Concrete
Binder
 
 
 
 
Figure 2.18 - Drying Shrinkage versus Age (Kim et al. 1998) 
 
In contrast, experiments performed by Raghavan et al. (2003) indicate that for 
their research the conventional concrete specimens exhibited more drying shrinkage than 
the SCC specimens.  The materials used for SCC were the same as conventional concrete 
with material proportions for SCC consisting of a lower water-to-binder ratio and a 
 43
higher sand-to-aggregate ratio.  In addition, the water weight for the conventional 
concrete and the SCC was the same in all cases.  A summary of the results from this 
study can be seen in Figure 2.19.  The results indicate that the drying shrinkage of SCC 
was 25% less than conventional concrete.  It is suggested that this reduction in shrinkage 
can be attributed to the effect of paste volume and decreased water-to-binder ratio.  
Raghavan et al. (2003) reports that for the same water content and decreased water-to-
binder ratio, the drying shrinkage is reduced in SCC.   
 
 
Figure 2.19 - SCC versus Normal Concrete (Raghavan et al. 2003) 
 
Further studies conducted by Attiogbe et al. (2003) evaluated the effect of the 
sand-to-aggregate ratio on drying shrinkage of SCC.  SCC mixtures were prepared at a 
cement content of 850 lb/yd
3
, water-to-cementitious ratio of 0.34, and sand-to-aggregate 
ratios of 0.58, 0.48, and 0.39, respectively.  It can be seen from Figure 2.20 that as the 
sand-to-aggregate ratio increased the drying shrinkage also increased.  This report 
indicates that increasing the sand-to-aggregate ratio can have an effect on the drying 
shrinkage.   
 44
 
 
Figure 2.20 - Drying Shrinkage versus Sand-to-Aggregate Ratio (Attiogbe et al. 2003) 
 
2.4.4 Permeability  
 Permeability is an important factor in the durability of concrete structures because 
it controls the entry rate and the movement of moisture that may contain aggressive 
chemicals (Mindess et al. 2003).  The permeability of concrete is related to the pore 
system within the bulk of the hardened cement paste and the zone near the interface 
between the cement paste and the aggregate (Neville 1996).  Thus, the permeability of 
concrete is not just a simple function of the porosity, but depends on the size, shape, 
distribution, and continuity of the pores within the paste (Neville 1996).  Neville (1996) 
suggests that the permeability of hardened cement paste is controlled by its capillary 
porosity as shown in Figure 2.21.  Furthermore, Figure 2.22 shows that the capillary 
volume increases rapidly for water-to-cementitious ratios greater than 0.42.   
 
 
 45
 
 
Figure 2.21 ? Coefficient of Permeability versus Capillary Porosity (Neville 1996) 
 
 
Figure 2.22 ? Coefficient of Permeability versus Water-to-Cement Ratio (Neville 1996) 
 
 46
The permeability of concrete is also influenced by the properties of the 
cementitious materials and presence of aggregate.  The interfacial transition zone, which 
has a different microstructure than the bulk paste as well as a locus of microcracking, can 
make up one-third to one-half of the total volume of the hardened cement paste (Neville 
1996).  As a result, the interfacial transition zone can be expected to contribute to the 
permeability of concrete.  However, it is argued that if the aggregate has low 
permeability, its presence reduces the effective area that flow may take place and the 
effective flow path becomes longer so that the permeability of concrete may be reduced 
(Neville 1996).  Thus, the presence of the interfacial transition zone on the permeability 
still remains uncertain.  Nevertheless, SCC typically incorporates high amounts of fine 
material and low water-to-binder ratios, which may lead to a denser microstructure within 
the bulk paste as well as the interfacial transition zone.  Thus, it would be expected that 
SCC has a lower permeability compared to conventional concrete.   
Research conducted by Raghavan et al. (2003) reported on rapid chloride 
penetration tests (RCPT) values of SCC ranging from 1100-1500 coulombs and an 
average of 4000 coulombs for conventional concrete.  Figure 2.23 shows the results from 
this study.  Raghavan et al. (2003) concludes that the reduction in permeability is due to 
the high filler material and lower water-to-binder ratio for the SCC mixtures.  This 
allowed the SCC to develop a denser microstructure than the conventional concrete with 
higher water-to-cementitious ratios.  Studies conducted by Attiogbe et al. (2003) also 
indicate that the porosity of SCC was found to be lower than conventional concrete, 
indicating the potential for better long-term durability for SCC compared to conventional 
concrete.  Thus, it can be determined that even at the same water-to-cementitious ratios, 
 47
SCC mixtures can produce a denser microstructure than conventional concrete due to 
better particle packing.  
 
 
  
 
Figure 2.23 - RCPT Values of SCC and Normal Concrete (Raghavan et al. 2003) 
 
 
2.5 SUMMARY AND CONCLUSIONS 
 
? Self-consolidating concrete is able to fill formwork, encapsulate reinforcement 
bars, and consolidate under its own weight.  At the same time it is cohesive 
enough to maintain its homogeneity without segregation or bleeding.   
? Rilem Report 23 from Technical Committee 174-SCC (Skarendahl 2000) 
suggests that three main functional requirements of SCC are as follows: 
a. Filling Ability: The ability of the concrete to completely fill formwork 
and encapsulate reinforcement without the use of external vibration. 
b. Passing Ability: The ability of the concrete to pass through restrictive 
sections of formwork and tightly spaced reinforcement bars without 
blockage due to interlocking of aggregate.  
 48
c. Segregation Resistance: The ability of the concrete to keep particles in a 
homogenous suspension throughout mixing, transportation, and 
placement. 
? The slump flow test is one of the most common and popular test to evaluate the 
deformation capacity of SCC because the procedure and apparatus is relatively 
simple.   
? One of the most critical requirements for SCC is that it must not segregate during 
or after placement. 
? The VSI rating of the slump flow patty is considered part of the dynamic stability 
given the fact the concrete can exhibit some non-uniform texture following some 
mixing and transport; whereas, the VSI can be considered as a static stability 
index when it is observed in the wheelbarrow or mixer following some period of 
rest time.   
? The L-Box and J-Ring is used to assess the passing ability of a SCC mixture.   
? The segregation column test is used to determine the stability and segregation 
resistance of a SCC mixture.   
? The following actions should be taken to achieve adequate filling ability (Khayat 
and Tangtermsirikul 2000): 
o Increase the deformability of the paste. 
1. Balanced water/powder ratio (Balanced so that adequate 
deformability and deformation velocity can be achieved) 
2. Superplasticizers 
 
 
 
 49
o Reduced interparticle friction. 
1. Low coarse aggregate volume 
2. Higher paste content 
 
? To achieve suitable passing ability the following steps should be considered 
(Khayat and Tangtermsirikul 2000): 
o Enhance the cohesiveness to reduce segregation of aggregate. 
1. Low water/binder ratio 
2. Viscosity modifying admixture 
 
o Compatible clear spacing and aggregate characteristics. 
1. Low coarse aggregate content 
2. Small maximum aggregate size 
 
? The following steps should be considered to produce sufficient segregation 
resistance (Khayat and Tangtermsirikul 2000): 
o Reduce the segregation of solid particles. 
1. Reduced maximum size aggregate  
2. Low water/powder ratio 
3. Viscosity modifying admixture 
 
o Minimize bleeding due to free water 
1. Low water content 
2. Low water/powder ratio 
3. Powders with high surface area 
4. Viscosity modifying admixture 
 
? The porosity relationship can be considered one of the most important factors in 
cement based materials because it affects both the cement paste matrix and the 
interfacial transition zone (ITZ). 
 50
? The modulus of elasticity of concrete is affected by the modulus and volume 
fraction of the aggregate.  
? When the elastic modulus of the fine and coarse aggregate are not much different 
and the total volume fraction of aggregate is constant, the elastic modulus of SCC 
is not significantly affected by the sand-to-aggregate ratio. 
? Shrinkage of concrete is a function of the paste properties, and the most important 
parameter is exerted by the aggregate, which will restrain the shrinkage. 
? Even at the same water-to-cementitious ratios, SCC mixtures can produce a 
denser microstructure than conventional concrete due to better particle packing 
resulting in lower permeability values.  
 
 51
 
 
 
 
CHAPTER 3 
 EXPERIENCES WITH DRILLED SHAFT CONCRETE 
A review of literature relevant to experiences with drilled shaft concrete is 
presented in this chapter.  This chapter will address several aspects of design and 
construction that are essential for high-quality drilled shaft concrete and problems that are 
encountered in drilled shaft construction that may lead to poor quality drilled shaft 
foundations.  Selected examples of more common problems associated with drilled shaft 
concrete are cited in this chapter so that the mechanisms that cause these problems can be 
understood.  The literature presented in the FHWA Drilled Shaft Manual, ?Construction 
Procedures and Design Methods? (O?Neill and Reese 1999) is considered to be the 
current state of practice for drilled shaft design and construction.  Therefore, it is 
recommended that the FHWA Drilled Shaft Manual, ?Construction Procedures and 
Design Methods? (O?Neill and Reese 1999) be reference material for the reader not 
familiar with drilled shaft concrete, construction procedures, and design.  It must be noted 
that the problems associated with drilled shaft concrete and cited examples in this chapter 
are not based on the author?s experience.  Rather they are based on observations and 
experience of other experienced engineers.   
 
3.1 INTRODUCTION 
 Recently developed techniques in integrity and load testing have given engineers 
and contractors the ability to assess the quality of drilled shaft foundations after they have 
52 
been cast.  These techniques have also provided insight to problems that are associated 
with materials and construction practices that have lead to defects or less than optimal 
performance in drilled shaft foundations.  Some of the most common issues that comprise 
the quality of drilled shaft foundations due to drilled shaft concrete come from the failure 
to consider one or more of the following: 
1. Retained workability of the concrete mixture for the duration of the pour 
2. Blockage of the coarse aggregate due to congested rebar cages  
3. Segregation and bleeding of the drilled shaft concrete 
 
3.2 WORKABILITY OF DRILLED SHAFT CONCRETE 
 A number of terms are commonly used to describe a different aspect of concrete 
behavior: consistency, flowability, pumpability, and compactability (Mindess et al. 
2003).  Workability is often used to represent all the terms mentioned above; however, 
these terms are often subjective and mean different things to different people.  Therefore, 
a more precise definition should be given to describe this property of a concrete mixture.  
Mindess et al. (2003) states that workability is described in terms of the amount of 
mechanical work or energy required to achieve full compaction of a concrete mixture 
without segregation.  Other definitions provided by ASTM and ACI suggest that 
workability can be defined as the effort required to manipulate the fresh concrete without 
the loss of homogeneity (ASTM) or the ease in which concrete can be mixed, placed, 
consolidated, and finished (ACI) (Neville 1996).  In drilled shaft construction, full 
compaction or consolidation of a concrete mixture must be achieved without the use of 
external energy.  For drilled shaft concrete, O?Neill and Reese (1999) describe the 
53 
workability in terms of the ability of a concrete mixture to readily flow through the 
tremie, flow laterally through rebar cage, and impose a high lateral stress against the sides 
of the borehole wall without the use of external vibration.  As a result, high workability is 
one of the most important characteristics for drilled shaft concrete. 
There have been many methods developed over the years to determine the 
workability of concrete mixture: slump test, compaction test, flow test, and Vebe test.  
However, the slump test, ASTM C 143 (1998), is the oldest and most widely used test for 
determining the workability of a concrete mixture for drilled shaft construction (O?Neill 
and Reese 1999).  Although some organizations such as the California Department of 
Transportation (Caltrans) use ASTM C 360 (1998) ?Standard Test Method for Ball 
Penetration in Freshly Mixed Hydraulic Cement Concrete? in lieu of the slump test.  
ASTM C 360 (1998) correlates the depth of penetration of 30 ? 0.1 lb cylinder with a 
hemispherical shaped bottom with results of ASTM C 143 (1998).  It should be noted that 
these tests do not measure the true workability of concrete mixture, but rather is a 
measure of consistency.  However, a concrete mixture with the same consistency may 
vary in workability.  Nevertheless, these tests are very useful in detecting variations in a 
concrete mixture, and it gives an indication of how a drilled shaft concrete mixture will 
perform.   
FHWA recommendations for drilled shaft concrete state that a slump of 6 inches 
or higher should be used for the dry method, and 8 inches when the wet or casing method 
is used (O?Neill and Reese 1999).  The FHWA guidelines go on to advise that good 
drilled shaft concrete should have an appearance of collapsible concrete that will fall 
freely when the slump cone is removed (O?Neill and Reese 1999).  Brown (2004) 
54 
suggests that experienced workers often describe quality drilled shaft concrete as having 
a creamy paste rather than a boney texture.  Figure 3.1 shows a drilled shaft concrete 
mixture that is on the lower end of allowable slump values that may be suitable for dry-
hole construction.  Figure 3.2 shows a drill shaft concrete mixture that may be suitable 
for both dry and wet-hole construction.  
 
 
 
 
 
 
 
 
 
 
 
Figure 3.1 ? Drilled Shaft Mixture with a Slump of Approximately 6.5 Inches  
                     (Annual ADSC Short Course) 
 
 
 
 
 
 
55 
 
 
                                                           
 
 
 
 
 
 
 
 
Figure 3.2 ? Drilled Shaft Mixture with a Slump of 8-9 Inches (O?Neill and Reese   
                     1999) 
 
O?Neill and Reese (1999) state that to achieve the high workability that is needed 
for drilled shaft concrete, a high water-to-cementitious ratio ranging from 0.5 to 0.6 can 
be used without the use of water reducers or incorporation of water reducers with a 
water-to-cementitious ratio of 0.45 or less.  The former relies on more than half the water 
provided to lubricate the mix during concrete placement that is not necessarily needed for 
hydration.   The latter relies on water reducers to reduce the amount of mixing water 
required to produce concrete of a certain slump by reducing the interparticle friction 
between the cement particles and water.  Low-, mid-, and high-range water reducers 
(superplasticizers) have been used in drilled shaft construction.  O?Neill and Reese 
(1999) suggest that with high-range water reducers, water-to-cementitious ratio as low as 
0.3 can be used while maintaining a high slump.   
56 
Another important aspect of drilled shaft concrete in terms of workability is the 
consideration of the aggregate type and gradation.  In general, rounded aggregate is 
typically preferred over crushed aggregate due to the increased workability for a given 
water content.  Rounded aggregates will act like ?ball bearings? while crushed aggregates 
will have more mechanical interlock and require more work to overcome internal friction 
(Mindess et al. 2003).  The FHWA guidelines recommend that a well-graded coarse 
aggregate with a maximum size aggregate of ? in. be used (O?Neill and Reese 1999).  
The main reasons for these recommendations are to minimize the amount of paste in the 
mix, provide a concrete mixture that can readily flow through the rebar cage without any 
bridging of the aggregate at the vicinity of the reinforcement, and to prevent segregation 
of the concrete mixture (O?Neill and Reese 1999, and Brown 2004). 
 When tremie placement or temporary casing is utilized it is not only important to 
have sufficient workability initially, but it is also critical to maintain the workability for 
the duration of the pour.  Controlled setting of the concrete mixture is necessary to allow 
for any construction delays in concreting, and to allow the temporary casing to be 
removed after concreting is completed.  In general, set-retarding admixtures are used to 
control the setting that is necessary to complete the construction sequence.  Set-retarding 
admixtures can be classified into 5 major categories (Mindess et al. 2003): 
? Lignosulfonic acids and their salts 
? Hydroxycarboxylic acids and their salts 
? Sugars and their derivatives 
? Phosphates and organic phosphate salts 
? Salts and amphoteric metals such as lead, zinc, and tin  
57 
Set-retarding admixtures slow down the rate of early hydration of C
3
S by 
extending the length of the induction stage which extends the setting times as determined 
by ASTM C 403 (1998) (Mindess et al. 2003).  Mindess et al. (2003) states that organic 
retarders are able to absorb into the nuclei of the calcium hydroxide and inhibit their 
growth; however, once the acceleration stage of the hydration process begins the 
hydration proceeds as normal.  Mindess et al. (2003) goes on to report that when 
inorganic retarding admixtures are utilized, they can form a coating around the C
3
S 
particles that can severely reduce the rate of reaction.  The extended length of the 
induction stage will depend on the effectiveness of the retarder and the amount added.  
Furthermore, replacement of cement by less reactive supplementary cementitious 
materials, such as fly ash, can also increase the time in which the concrete will remain 
workable.   
 Recent results from integrity and load testing have shown that inadequate 
workability or loss of workability during the duration of concrete placement can lead to 
defects that are unfavorable for drilled shaft foundations.  When drilled shaft concrete has 
insufficient workability the following problems can arise:  
 
PROBLEM NO. 1- When tremie placing concrete as shown in Figures 3.3, the concrete 
should readily flow through the tremie, rebar cage, and displace the drilling slurry 
upward in one uniform horizontal layer.  However, if workability is not maintained for 
the duration of the pour there is a probability that debris can become entrapped causing 
structural defects within the shaft as shown in Figure 3.4.  The debris can come from 
suspended particles in drilling slurry, sloughed soil, and laitance settling onto the top of 
58 
the rising column of concrete.  This debris can become entrapped when the concrete has 
sufficient workability when delivered to the job site, but over time loses its workability 
within the shaft.  In this case, while the oldest concrete is riding on top of the rising 
column of concrete its beginning to have insufficient workability that may potentially 
lead to a difference in head between the outside of the rebar cage and the inside of the 
rebar cage.  The fresh concrete being placed in the shaft will tend to erupt through this 
stiff concrete and trap debris that is on the outside of the rebar cage leading to structural 
defects.  Furthermore, the loss of workability may also result in plugging of the tremie 
pipe because the oldest concrete has become too stiff to allow the fresh concrete to 
readily flow out of the tremie pipe.  The contractor may make aggressive attempts to 
clear the tremie pipe and unintentionally or purposely extract the tremie resulting in 
debris seams to become entrapped or cause contamination of the concrete as shown in 
Figure 3.5.  These construction issues are illustrated in Figures 3.4-3.10. 
 
 
 
 
 
 
 
 
 
 
 Figure 3.3 - Illustration of Tremie Placement (O?Neill and Reese 1999) 
59 
 
Geomaterial
Drilling Slurry
Rebar Cage
Concrete
Tremie Pipe
Debris
Water Table
 
 
 
 
 
 
 
Geomaterial
Drilling Slurry
Rebar Cage
Tremie Pipe
Concrete
Debris
Water Table
(A) Fresh concrete with sufficient                  (B) Interruption in concrete supply  
workability being placed within                      allows concrete to loss its workability 
the shaft.                                                          within the shaft. 
 
 
  
 
 
 
 
 
 
Geomaterial
Drilling Slurry
Rebar Cage
Concrete
Tremie Pipe
Entrapped 
Debris
(C) After concrete placement resumes,          (D) Completed shaft with large pockets 
the fresh concrete that is introduced               of entrapped debris and voids. 
erupts through the stiff concrete and                  
entraps debris on the outside of the  
rebar cage. 
 
Figure 3.4 - Illustration of Entrapped Debris due to the Eruption of Fresh Concrete  
                    through Stiff Concrete 
 
Water Table
Entrapped 
Debris
Geomaterial
Rebar Cage
Concrete
Voids
Water Table
60 
 
 
 
 
 
  
 
 
Geomaterial
Drilling Slurry
Rebar Cage
Tremie Pipe
Concrete
Debris
Water Table
Geomaterial
Drilling Slurry
Rebar Cage
Concrete
Tremie Pipe
Debris
Water Table
(A) Fresh concrete with sufficient               (B) Interruption in concrete supply  
workability being placed within                   allows concrete to loss its workability 
the shaft.                                                       within the shaft. As concrete placement 
                                                                      resumes, the tremie becomes plugged. 
 
 
 
 
 
 
 
 
 
Geomaterial
Drilling Slurry
Rebar Cage
Concrete
Tremie Pipe
Debris
Extracting Tremie
Water Table
Geomaterial
Rebar Cage
Concrete
Entrapped 
Debris
Water Table
(C) The contractor accidentally                    (D) Completed shaft with debris seams  
or purposely extracts the tremie to                due to the extraction of the tremie. 
restart the flow again. 
 
Figure 3.5 ? Illustration of Entrapped Debris Seams due to Extraction of the Tremie  
 
61 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.6 - Example 1 of Shaft Defects due to the Loss of Workability (photograph  
                    courtesy of Dr. Dan Brown) 
 
 
 
 
Figure 3.7 - Example 2 of Shaft Defects due to the Loss of Workability (TxDOT) 
 
62 
 
Figure 3.8 - Example 3 of Shaft Defects due to the Loss of Workability (TxDOT) 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.9 - Example 4 of Shaft Defects due to the Loss of Workability (Caltrans) 
63 
 
Figure 3.10 - Example 5 of Shaft Defects due to the Loss of Workability (TxDOT)  
 
PROBLEM NO. 2- When concrete is placed into a cased hole as shown in Figure 3.11, 
there is a need for the concrete to maintain its workability throughout the duration of the 
pour.  This maintained workability is essential because when the casing is removed the 
concrete must be able to flow laterally to displace any water that is present outside the 
casing, and produce a high lateral stress on the soil or rock so that there is adequate bond 
between the concrete and surrounding bearing stratum.  Furthermore, if the concrete 
workability is lost before the casing is pulled, the casing may be very difficult to remove 
or in some cases not be able to be removed at all.  If the casing is able to be removed, the 
concrete can tend to arch and be lifted with the casing causing a neck to be formed.  
Figure 3.13 shows an example when the concrete workability was lost before the casing 
was extracted.  As a result, the concrete on the outside of the rebar cage was lifted along 
with casing leaving the rebar cage exposed.  Even if no necking occurs, a stiff column of 
concrete has essentially been ?slipped formed? into an oversized hole.  As a result, the 
64 
concrete can impose little or no lateral stress on surrounding soil or rock, and it can be 
expected that adequate bond between the concrete and bearing stratum will not be 
present.  In addition, the presence of heavily congested rebar cages may also make 
matters worse because the concrete can be restricted by the cage after the casing is 
removed.  The mechanism that may lead to poor defects when the casing is pulled is 
schematically shown in Figure 3.12.  
 
 
 
 
 
 
 
 
 
 
   
 
 
Figure 3.11 ? Illustration of a Cased Hole (FDOT) 
 
 
 
 
 
65 
 
 
Cohesive 
Geomaterial
Rebar Cage
Concrete
Casing
Caving Soil
Extracting Casing
Necking and
Arching
 
 
 
 
 
 
 
 
 
Cohesive 
Geomaterial
Rebar Cage
Concrete
Casing
Caving Soil
Free Fall Placement
(A) Concrete being placed using                   (B) Concrete placement is complete, but 
casing method.                                               due to long periods of placement or  
                                                           construction delays the concrete workability 
                                                           has been lost. The casing is extremely                                     
                                                          difficult to remove and causes arching   
                                                          and necking to occur 
 
 
 
 
 
 
 
 
 
 
Necking and 
Arching
Cohesive 
Geomaterial
Rebar Cage
Concrete
Casing
Caving Soil
Extracting Casing
Loss of bond 
between geomaterial
and concrete
Cohesive 
Geomaterial
Rebar Cage
Concrete
Necking and
Arching
Caving Soil
(C) As casing is being extracted,                   (D) After the casing is pulled, the shaft has  
loose material may slough into the                pockets of entrapped debris and loss of bond 
neck and entrap debris.                                  between the bearing stratum and concrete. 
 
Figure 3.12 ? Necking and Arching due to the Extraction of the Casing when   
                      Workablility is Lost 
 
 
66 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.13 - Shaft Defects due to the Extraction of the Casing (Annual ADSC Short  
                     Course) 
 
One can infer from the discussion and illustrations above that the loss of concrete 
workability can have detrimental effects on drilled shaft foundations.  Therefore, careful 
attention must be exercised by contractors and engineers to ensure that concrete 
workability be maintained.  To ensure that proper workability and slump retention is 
achieved, O?Neill and Reese (1999) recommend that trial mixes should be conducted 
with the cementitious materials, aggregates, and additives that will be used for a 
particular application.  They further state that a trial mix study for drilled shaft concrete 
should consist of constructing a graph of slump loss versus time after batching as shown 
in Figure 3.14.  Figure 3.14 illustrates a slump loss relationship in which the slump loss 
diminishes slowly and exceeds 4 inches after 4 hours.  Figure 3.14 also demonstrates an 
67 
undesirable slump loss wherein the initial workability is sufficient, but slump loss occurs 
rapidly after batching.   
 
 
 
 
 
 
 
 
 
Figure 3.14 ? Slump Loss versus Time Relationship (O?Neill and Reese 1999)  
When constructing the slump loss graph, contractors and engineers should 
exercise care to make certain that the conditions that existed for the trial mixes continue 
to exist during construction.  If any conditions change, such as cementitious materials, 
aggregate source, or ambient temperature, new trial mixes should be conducted to ensure 
the proper slump loss is achieved (O?Neill and Reese 1999).  For example, the use of 
different cementitious materials, whether it be using the same type of cement from a 
different company or change in cement type all together, may increase or decrease the 
rate of slump loss depending on the fineness and chemical composition.  Figure 3.15 
shows that for constant mixture proportions, a change in cement brand can increase or 
decrease the rate of slump loss over time.  Reconstruction of the slump loss graph versus 
time is particularly important when the laboratory temperatures do not reflect field 
68 
temperatures, which strictly speaking the concrete temperature itself is the most 
important.  If the field temperatures are higher than laboratory temperatures, the slump 
loss graph is misleading since slump loss is accelerated in hot weather conditions. 
O?Neill and Reese (1999) report that an increase in 18 deg. F will increase the rate of 
slump loss by a factor of approximately 2. 
 
 
Figure 3.15 ? Slump Loss at 70
o
F for Two Different Brands of Type I Cement  
                      (Mindess et al. 2003) 
 
 
O?Neill and Reese (1999) determined that 4 inches after 4 hours would be 
appropriate because ordinarily this is the maximum amount of time that is required for 
concrete placement.  However, drilled shafts today are being constructed with larger 
diameters at deeper depths that require long periods of time for concrete placement.  
Long periods for concrete placement may also be required where the construction site is 
difficult to access or unforeseen construction delays occur.  Unfortunately, many state 
DOT?s still use this specification that routinely calls for a slump of 4 inches be 
maintained after 4 hours.  For that reason, Brown (2004) suggests that based on his 
69 
experience and observations that this recommendation is not adequate for many 
conditions.  For example, if contractual documents require a contractor to maintain 4 
inches of slump after 4 hours, but the drilled shaft requires 6 hours for concrete 
placement, the requirement of 4 inches after 4 hours will be insufficient for that 
application.  Although the contractor may have supplied a mixture that maintained 4 
inches of slump after 4 hours, by the time concrete placement is complete the workability 
of the concrete mixture has diminished greatly below 4 inches, which may produce 
undesirable results.  Brown (2004) proposes that the concrete mixture maintain a high 
workability, a slump loss of no more than 2 inches, for the duration of the concrete 
placement no matter what that period may be.  In that case, not only will the concrete 
maintain high workability for the duration of the concrete placement, it will also prevent 
two very dissimilar fluids from interacting. 
 
Case Study 1 (after Brown 2004) 
 
 
 
 
 
 
Figure 3.16 - Shaft Defects due to the Loss of Workability (left), After Removal of  
                      Surface Flaws for Repairs (photograph courtesy of Dr. Dan Brown) 
 
 In this example, drilled shafts were used to support individual columns for a 
bridge over a lake in the southwest United States.  The upper portions of the shafts were 
70 
formed by using removable casing that was extended through the lake.  It can be seen 
from Figure 3.16 that the rebar cage had reasonably large openings that typically 
measured 8 inches between the transverse and longitudinal reinforcement.  In this 
instance the rebar cage was not restrictive to concrete flow.  The concrete was placed 
using a gravity-fed tremie.  Each shaft required 5 to 6 concrete trucks with each shaft 
taking 4 to 6 hours to complete the concrete pour. 
  After the removal of the forms, the shaft appeared to have weak pockets of 
cemented materials.  The cemented material seemed to be mortar-like with no presence of 
coarse aggregate within the pockets.  The pockets were easily chipped away using a 
hammer revealing large voids within the shaft.  Figure 3.16 illustrates these weak pockets 
before they were chipped away for repairs (left), and the voids that were present after the 
mortar-like material was removed (right).  After close examination of the shafts it was 
determined that the concrete did not maintain sufficient workability for the duration of 
the pour during the hot summer months.  As the concrete moved up in the shaft, the 
tremie would be lifted from the bottom of the shaft, but always maintained at least 7 feet 
below the surface of the concrete.  However, the previously placed concrete began to lose 
its workability and became stiff within the shaft.  The fresh concrete placed in the shaft 
through the tremie pipe that was below the surface of this stiff concrete erupted through 
the stiff concrete rather than lifting the concrete in one uniform layer.  When this 
occurred, the debris that had been riding on top of the column of concrete became 
entrapped on the outside of the rebar cage causing the surface flaws. 
 
 
71 
Case Study 2 (after O?Neill and Reese 1999) 
 
 
  
 
 
 
 
 
 
 
Figure 3.17 - Shaft Defects due to the Loss of Workability from Construction Delays  
                      (O?Neill and Reese 1999) 
 
In this example, concrete was being placed by a gravity-fed tremie with the 
concrete being delivered to the tremie by means of pumping.  Figure 3.17 reveals that 
rebar cage had relatively large openings that were not particularly resistive to concrete 
flow.  While concrete placement was taking place there was an interruption in the 
concrete supply.  The interruption in concrete delivery allowed the previously placed 
concrete to become stiff within the shaft.  When the concrete placement resumed the 
fresh concrete that was introduced below this now stiff concrete erupted through the stiff 
concrete.  As a result, the debris that was riding on top of the rising column of concrete 
became entrapped on the outside of the rebar cage.  As the entrapped debris was removed 
for repair, large voids within the shaft were revealed as shown in Figure 3.17.   
72 
Case Study 3 (after Gerwick 2004) 
 Gerwick (2004) illustrates an instance where several thousand yards of concrete 
was to be tremie placed. The night supervisor was rushing to complete the job in record 
time.  In an effort to speed up the concrete placement, the night supervisor opened the 
concrete buckets rapidly so that the tremie pipe can be moved up at a rapid rate to get the 
concrete to flow faster.  However, when plugging of the tremie pipe occurred, the night 
supervisor made aggressive attempts to free the plugs by raising and dropping the tremie.  
Although the project was completed rapidly, a subsequent diver investigation revealed 
that seams of gravel and trapped pockets of laitance were buried under sound structural 
concrete.  By extracting the tremie pipe out of the concrete to restart the flow again, the 
night supervisor consequently entrapped the laitance and debris that was riding on top of 
the column of concrete.   
 
Case Study 4 (after Brown 2004) 
 In this example, a drilled shaft was constructed through approximately 40 feet of 
soil and socketed into approximately 10 feet of underlying rock formation using casing 
for the full depth.  The casing was utilized to allow downhole visual inspection of the 
bottom of the shaft.  The drilled shaft was to be load tested using an Osterberg cell that 
was placed at the base of the rock socket.  After inspection was completed, the Osterberg 
cell and rebar cage was placed in the shaft, concrete was then placed in the rock socket 
and the casing removed.  After the concrete was allowed to cure for some period, the 
shaft was load tested using this Osterberg cell.  The Osterberg cell mobilized 112.4 kips 
of side shear resistance.  This side shear resistance was found to be only a small fraction 
73 
of what was expected.  For comparison, another drilled shaft was constructed in the same 
manner.  However, this time the wet-hole method was utilized without casing into the 
rock.  The concrete was then placed into the drilled shaft using a tremie pipe.  After the 
concrete was allowed to cure for some period, the shaft was load tested and the Osterberg 
cell was found to mobilize over 2248 kips of side shear resistance.  
 It can be seen from the information provided above that the two different methods 
of placement provided very different results.  It was concluded that the time required for 
removal of the casing after concrete placement allowed the concrete to lose its 
workability to a point that the concrete was essentially ?slip formed? into an oversized 
hole within the rock socket.  As a result, the concrete did not provide sufficient lateral 
pressure against the rock socket when the casing was removed resulting in low side shear 
resistance.  It was also believed that because the concrete could not provide sufficient 
lateral pressure on the rock socket that the debris behind the casing could not be 
displaced when the casing was removed, which consequently could have contaminated 
the bond between the concrete and rock.    
 
3.3 COMPATIBILITY BETWEEN CONGESTED REBAR CAGES AND  
      CONCRETE  
 
 Improved equipment and appropriate construction techniques have allowed 
contractors to construct very large diameter drilled shafts at great depths.  These large 
diameter shafts have advantages for structures that experience large lateral and 
overturning loads that are produced by seismic loads, vessel impacts, and wind.  Single 
large drilled shafts produce smaller footprints than piled footings, a benefit in terms of 
constructability when working in congested construction sites or nearby existing 
74 
structures (Brown 2004).  As a result, designers and engineers have increasingly designed 
and specified large diameter shafts.  The use of larger diameter shafts that are designed 
for large bending moments require high amounts of reinforcement bars to be placed 
within the shaft.  Consequently, the rebar cages have become progressively more 
congested and resistive to concrete flow.  The addition of numerous assess tubes for 
integrity testing has also lead to increased congestion in the rebar cages.  Although these 
large diameter shafts have numerous advantages; problems from resistive rebar cages can 
occur in the following ways:  
 
PROBLEM NO. 1- When closely spaced reinforcement bars are utilized, there is an 
increased probability that debris will be entrapped in the annular space outside the rebar 
cage.  The debris is entrapped when the lateral flow of the concrete is significantly 
impeded, which Gerwick (2004) describes as screening of the concrete, resulting in an 
elevation difference between the inside and outside of the rebar cage.  As a result, any 
debris that is accumulated on top of the rising column of concrete has a natural tendency 
to slough off into the annular space outside the rebar cage.  As additional fresh concrete 
is placed into the shaft, the fresh concrete will eventually flow laterally through rebar 
cage entrapping the debris as shown in Figure 3.18.  Figure 3.19 illustrates the elevation 
difference due to screening of the concrete flow, while Figure 3.20 shows shaft defects 
that can occur when the concrete flow is impeded by heavily congested rebar cages. 
 
 
 
75 
 
Geomaterial
Drilling Slurry
Rebar Cage
Tremie Pipe
Concrete
Debris
Water Table
 
 
 
 
 
 
 
 
Drilling Slurry
Rebar Cage
Tremie Pipe
Concrete
Debris
Geomaterial
Water Table
(A) Fresh concrete being placed within          (B) Heavily congested rebar cage begins         
the shaft.                                                           to screen the concrete causing a elevation                            
                                                                         difference between the inside and outside 
                                                                         rebar cage. 
 
 
 
 
 
 
 
 
 
Geomaterial
Drilling Slurry
Rebar Cage
Tremie Pipe
Concrete
Debris
Water Table
Rebar Cage
Concrete
Debris
Geomaterial
Water Table
(C) Fresh concrete placed in the                     (D) Completed shaft with entrapped 
shaft flows laterally entrapping                      debris due to heavily congested rebar 
debris.                                                              cage.  
 
Figure 3-18 Screening of the Concrete due to Heavily Reinforced Rebar Cages 
 
76 
 
 
 
 
 
 
 
 
 
 
Figure 3.19 - Elevation Difference between the Inside and Outside of a Rebar Cage  
                      due to Screening of the Concrete Flow (photograph courtesy of Dr. Dan  
                      Brown) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.20 ? Shaft Defects due to the Screening of the Concrete Flow  
                       (photograph courtesy of Dr. Dan Brown)  
 
77 
PROBLEM NO. 2 ? Even if tremie placement with clean slurry or placement by freefall 
is utilized; the concrete flow can become impeded to such an extent that large voids form 
outside the rebar cage.  This can occur when the reinforcement bars are so closely spaced 
that there is interlocking and bridging of the aggregate at the vicinity of the rebar cage.  
Interlocking and bridging of the aggregate may be increased when crushed stones are 
utilized or when the aggregate size is too large for the reinforcement spacing.  In other 
cases, the flow may become impeded to a standpoint that the lateral stress imposed by the 
concrete on the bearing stratum is diminished.   
The rebar cages for drilled shaft foundations consist of longitudinal bars that are 
distributed evenly around the outside and transverse (ties or spirals) reinforcement that is 
placed around the longitudinal bars.  The FHWA guidelines recommend that the clear 
spacing between bars be at least 5 times the maximum size aggregate (O?Neill and Reese 
1999).  Gerwick (2004) proposes that the largest possible bars be used, and spaced 3 to 4 
times the maximum size aggregate.  Brown (2004) expresses the fact that he has routinely 
seen these recommendations violated in practice.  Brown (2004) goes on to suggest that 
these recommendations are sometimes disregarded where seismic loads are significant.  
When seismic conditions exist, designers may use tight spiral confinement with a small 
pitch.  The FHWA guidelines would advise the use of pea sized gravel in such 
circumstances (O?Neill and Reese 1999).  The use of pea-sized gravel gives the mixture 
enhanced workability over crushed aggregate and decreases the probability of bridging of 
the aggregate at the vicinity of the rebar cage.  Brown (2004) suggests it is common 
practice that agencies allow the use of pea gravel, but does not specifically require the use 
of pea gravel in contractual documents.  Since pea gravel mixtures are more expensive on 
78 
a material basis, in many cases contracts may be allotted to contractors that may utilize a 
less expensive mix that uses crushed stones.  The result of such practice is that a concrete 
mixture may be chosen based on the lowest cost, rather than the one that is most 
appropriate for the conditions.  Designers should consider the consequences of tight 
reinforcement spacing and emphasize the workability in construction material so that 
constructability problems are minimized.  
 
Case Study 5 (after Brown 2004) 
 Single 13 foot diameter shafts were to be used to support oval shaped columns for 
a bridge in the western United States.  The shafts were to be socketed through overlaying 
alluvial sandy soil into sandstone.  The contractor cased through the overlaying sandy soil 
with temporary casing.  In order for the rebar cage in the shaft to match the shape of the 
column, designers used two rebar cages in which the two reinforcement cages overlap 
each other in a form of a fat figure 8 as shown in Figure 3.21.  In this application, the 
concrete mixture had to flow through two rebar cages that were heavily congested due the 
transverse reinforcement, which was rather restrictive to concrete flow. 
 
 
 
  
Rebar 
Cage
 
Figure 3.21 ?Oval Shaped Column with Figure 8 Rebar Cage (not to scale) 
79 
Subsequent integrity testing indicated large anomalies around the perimeter of 
several shafts.  Access shafts were constructed along side the drilled shafts where the 
anomalies were thought to be present.  The examination of the shafts revealed that large 
pockets of sand were entrapped where the two rebar cages overlapped.  After removal of 
the sand pockets, large voids remained in the outer perimeter of the shaft as shown in 
Figure 3.22.  Coring samples indicated that sound concrete with consistent compressive 
strengths within the center of the shaft, but unsound concrete with erratic compressive 
strengths was found to be around the perimeter of the shafts.   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.22 ? Shaft Defect due to Double Reinforcement Cages (photograph courtesy  
                       of Dr. Dan Brown) 
 
 
 
 
80 
Case Study 6 (after Brown 2004) 
 In this example test shafts were constructed for a new bridge in the eastern United 
States.  The test shafts were 8 feet in diameter and up to 160 feet deep with a rebar cage 
that consisted of heavy longitudinal reinforcement and spiral reinforcement at a 3.5 inch 
pitch.  The concrete mixture incorporated the use of crushed stone with a maximum size 
aggregate of ? inch and a slump of 8 inches.  As the concrete was being tremie placed, 
measurement and observations were made on the concrete behavior (Camp et al. 2002).  
The measurements taken indicated that a head difference between the inside and outside 
of the rebar cage of at least 4.5 feet.  Although small aggregate and a high slump concrete 
mixture were used in this project, observation from the concrete behavior showed there 
was still a potential for debris to become entrapped in annular space outside the rebar 
cage.  Therefore, designers and engineers should be cautious in such circumstances to 
ensure that the probability of entrapped debris is reduced, which may include the use of 
rounded pea gravel.    
 
3.4 SEGREGATION AND BLEEDING  
 In Section 3.2 it was stated that drilled shaft concrete should have excellent 
workability so that it can readily flow through the tremie, rebar cage, and the annular 
space between the rebar cage and borehole wall.  In addition to having high workability, 
drilled shaft concrete should exhibit sufficient cohesiveness to prevent segregation of the 
concrete mixture.  Segregation can be described as the separation of the constituents of a 
heterogeneous mixture so that the mixture is no longer uniform (Neville 1996).  The main 
81 
factors that contribute to the segregation of concrete mixture are listed below: (Mindess 
et al. 2003) 
? Larger maximum particle size over 1 inch and proportions of larger particles 
? High specific gravity of the coarse aggregate compared to that of the fine 
aggregate  
? A decreased amount in fines (sand or cement) 
? Changes in the particle shape away from well-rounded particles to crushed stones 
? Mixes that are too wet or dry 
 
In the case of drilled shaft concrete, the probability of segregation is increased due 
to the fact that dropping concrete from considerable heights by free fall or tremie 
placement, changes in direction of flow, discharging against obstacles, and considerable 
amount of handling all encourage segregation (Neville 1996).  In drilled shaft 
construction, segregation by handling may if the concrete must be delivered to a remote 
location without the continuous mixing of the concrete mixture for the entire time.  
Furthermore, any delay in concrete delivery during tremie placement can result in 
segregation within the concrete column inside the tremie, which can lead to plugging of 
the tremie and inclusions of non-uniform concrete within the shaft (Brown 2004).  Since 
these circumstances mentioned above frequently arise in drilled shaft construction, it is 
pertinent that designers ensure that a highly cohesive mixture with proper gradation of 
aggregate is used.  The use of smaller-rounded aggregate and a highly cohesive mixture 
will help to prevent sedimentation of aggregate particles in a concrete mixture (Neville 
1996, and Mindess et al. 2003).  
Bleeding is commonly regarded as a special form of segregation.  It is defined as 
the upward movement of mixing water to the surface of freshly placed concrete (Neville 
82 
1996).  Bleeding can be caused by the settlement of aggregate particles, and the inability 
of the concrete to hold the mixing water.  Since water has the lowest specific gravity, it 
segregates from the concrete mixture by rising to the surface of the freshly placed 
concrete (Mindess et al. 2003).  Although some bleeding is unavoidable and normal for 
good concrete, a significant amount of bleeding can result in inferior concrete.  This is 
true especially for tall elements such as columns and drilled shaft foundations.  As the 
bleed water moves upward to the surface of the shaft, the water-to-cementitious materials 
ratio in the lower portion of the shaft is decreased, but the bleed water trapped in the 
upper portion of the shaft causes an increase in the water-to-cementitious ratio, which 
may result in a reduction in strength (Neville 1996).  
The rising bleed water can also become trapped on the underside of coarse 
aggregate and reinforcement; thus, resulting in larger interfacial transition zones and loss 
of bond between the reinforcement and concrete as shown in Figure 3.23.  Furthermore, 
bleed water can travel upwards along the surface of casings forming a channel due to 
imperfections in the casing.  Neville (1996) reports that a preferred channel is formed 
resulting in surface streaking and distinct localized channels as shown in Figures 3.24 and 
3.25.  In Figures 3.24 and 3.25, drilled shafts were cast through a lake in the underlying 
soil using removable casing.  After the removable casing was removed, it was observed 
that bleed channels and surface streaks were formed along the outer perimeter of the shaft 
due to bleed water.  In other cases, vertical bleed channels are formed in the interior of 
the shaft.  These vertical bleed channels commonly form along the longitudinal 
reinforcement resulting in loss of bond between the reinforcement and concrete.   
 
83 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.23 ? Illustration of Bleeding in Freshly Placed Concrete (Mindess et al. 
                           2003) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.24 ? Example 1 of Bleed Channels and Surface Streaks due to Bleed Water 
                   Traveling along the Casing (photograph courtesy of Dr. Dan Brown) 
84 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.25 ? Example 2 of Bleed Channels and Surface Streaks due to Bleed Water 
                       Traveling along the Casing (photograph courtesy of Dr. Dan Brown) 
 
This high generation of bleed water can lead to increased porosity, reduced 
strength, increased permeability, reduced durability, and plastic shrinkage cracks.  
Therefore, it is necessary to control or limit the amount of bleed water generated.  This is 
especially true for large shafts at deep depths, where temporary casing is utilized, and 
when the wet-hole method is used in low-permeable soils.  In such cases, the generated 
bleed can not escape laterally as in highly permeable soils.  As a result, bleed water will 
escape vertically through bleed channels.  Under these circumstances, the use of high 
water-to-cementitious ratio concrete mixtures with high water contents may lead to low 
cohesive concrete mixtures that promote both segregation and bleeding.  In order to 
reduce the amount of bleeding Mindess et al. (2003) and Neville (1996) suggest that the 
following steps be taken to reduce the amount of bleed water generated: 
85 
? Increase the cement fineness or by using other finely divided supplementary 
cementitious materials  
? Through air entrainment, which is very effective 
? By reducing the water content or water-to-cementitious ratio 
? Presence of an adequate proportion of very fine aggregate particles, especially 
less than the #100 sieve 
 
Case Study 7  
 
Figure 3.26 - Shaft Defect due to Bleed Water Traveling along the Casing (TxDOT) 
 
In this example, drilled shafts were used to support columns over a bridge in the 
southwest United States.  The drilled shafts were cast through the lake into the underlying 
soil that consisted of sedimentary rock using approximately 60 feet of removable casing.  
Each shaft was approximately 6 feet in diameter and 80 feet deep.  After the removable 
86 
forms were removed, inspectors noticed bleed channels and surface streaks had formed 
along the outer perimeter of the shaft.  
 The use of removable casing and considering the fact that the shaft was placed 
into sedimentary rock forced the bleed water to travel vertically creating bleed channels 
and surface streaks as shown in Figure 3.26.  It can be determined from looking at Figure 
3.26 that the creation of bleed channels may result in a reduction in durability and 
increased permeability.  Careful attention must be exercised to ensure that bleeding is 
reduced by incorporating actions previously stated.  
 
3.5 SUMMARY AND CONCLUSIONS 
? Recently developed techniques in integrity and load testing have provided 
engineers and contractors with insight to problems that are associated with 
materials and construction practices that have lead to defects or less than optimal 
performance in drilled shaft foundations. 
? Some of the most common issues that comprise the quality of drilled shaft 
foundations due to drilled shaft concrete come from the failure to consider one or 
more of the following: 
1. Retained workability of the concrete mixture for the duration of the pour 
2. Blockage of the coarse aggregate due to congested rebar cages  
3. Segregation and bleeding of the drilled shaft concrete 
? In drilled shaft construction, full compaction or consolidation of a concrete 
mixture must be achieved without the use of external energy. 
? Workability is one of the most important characteristics for drilled shaft concrete.  
87 
? Another important aspect of drilled shaft concrete in terms of workability is the 
consideration of the aggregate type and gradation. 
? When tremie placement or casing is utilized it is not only important to have 
sufficient workability initially, but it is also critical to maintain the workability for 
the duration of the pour. 
? If workability is not maintained for the duration of the pour there is a probability 
that debris can become entrapped causing structural defects within the shaft. 
? To ensure that proper workability and slump retention is achieved, trial mixes 
should be conducted with the cementitious materials, aggregates, and additives 
that will be used for a particular application. 
? When closely spaced reinforcement bars are utilized the lateral flow of the 
concrete is significantly impeded resulting in an elevation difference and 
interlocking and bridging of the aggregate at the vicinity of the rebar cage.  Debris 
accumulated on top of the rising column of concrete has a possibility of becoming 
entrapped on the outside of the rebar cage.  
? Drilled shaft concrete should exhibit sufficient cohesiveness to prevent 
segregation of the concrete mixture.   
? Rising bleed water can become trapped on the underside of coarse aggregate and 
reinforcement; thus, resulting in larger interfacial transition zones and loss of 
bond between the reinforcement and concrete. 
? Bleed water can travel upwards along the surface of casings forming a preferred 
channel resulting in surface streaking and distinct localized channels resulting in 
loss of bond between the reinforcement and concrete. 
88 
 
 
 
 
CHAPTER 4 
LABORATORY TESTING PROGRAM AND MATERIALS 
4.1 INTRODUCTION 
The objective of this research project is to evaluate the use of self-consolidating 
concrete as a viable material to be used in drilled shaft construction.  The laboratory 
testing program developed will examine the difference between ordinary drilled shaft 
concrete (ODSC) and self-consolidating concrete (SCC) for both fresh and hardened 
properties.  The fresh properties include filling ability, passing ability, segregation 
resistance, workability over time, bleeding characteristics, and setting.  The hardened 
properties include the comparison of the compressive strength, elastic modulus, 
permeability, and drying shrinkage.  Based on the results of the laboratory testing 
program, mixture proportions will be recommended for further evaluation during the 
construction of full-scale shafts in South Carolina.  
 
4.2 REQUIREMENTS FOR ODSC AND SCC MIXTURES  
 According to SCDOT specifications (2003), concrete for drilled shaft construction 
should be Class 4000 DS.  The specification for Class 4000 DS states that the concrete 
mixture shall meet the following criteria: 
? Minimum Cement per cubic yard???625 lbs. 
? Slump?????????????...7-9 inches 
? Maximum water-to-cementitious ratio?.0.43  
? 28-Day minimum compressive strength...4000 psi 
 89
? Air entrainment??????????.not required  
? Nominal coarse aggregate size????..3/4 inch 
? No. 67 aggregate gradation ?????..required  
Since a proposed field study will be conducted in South Carolina, all ordinary drilled 
shaft concrete (ODSC) mixtures prepared in the laboratory shall also conform to the 
above criteria.  However, due to the nature of this research the SCC mixtures will not 
conform to the above criteria set forth by the SCDOT with the exception of the required 
28-day minimum compressive strength of 4,000 psi.  Instead, the quality control limits 
for the SCC mixtures were based on past research and careful consideration of the drilled 
shaft construction issues discussed in Chapter 3.   
Yao and Gerwick (2004) report that slump flow value requirements for drilled 
shafts applications typically range from 14 to 18 inches.  In order to provide a concrete 
mixture with an increase in workability compared to the typical requirements provided 
above, it was determined that no SCC mixture should exhibit a slump flow less than 18 
inches at placement.  Research conducted at Auburn University by Hodgson (2003) 
indicates that when SCC is used in drilled shaft applications, a slump flow of 
approximately 24 inches can provide sufficient workability while showing limited signs 
of segregation.  Based upon this literature, it was concluded that a slump flow of 18 
inches would provide an increase in workability compared to ODSC and displace the 
drilling slurry upward in one uniform horizontal layer.  It was further determined that the 
upper slump flow value should be limited to 24 inches in order to prevent severe 
segregation, and slump flow values over 24 inches would not be needed to provide the 
necessary workability.  Moreover, a VSI rating of 1 or less was established in order to 
limit possible segregation of the concrete mixture during or after placement.  It must be 
 90
noted that mixture proportions for the base line SCC mixture utilized in Phases I-IV 
(3:41-48-FA) were based on recommendations provided by Su et al. (2001) ?A Simple 
Design Method for Self-Compacting Concrete?.  
All concrete mixtures prepared in the laboratory shall meet the ACI 318 (2002), 
?Building Code Requirements for Reinforced Concrete?, recommendations that specifies 
that the concrete mixtures should be proportioned to provide an average compressive 
strength (f?
cr
) which is higher than the required strength (f?
c
).  When adequate data are not 
available to establish a standard deviation it is recommended that the specified 
compressive strength (f?
c
), when ranging from 3,000 to 5,000 psi, be increased by 1,200 
psi.  Therefore, all concrete mixtures should have a critical average compressive strength 
(f?
cr
) of no less than 5,200 psi at 28-days to be considered acceptable. 
 
4.3 LABORATORY TESTING PROGRAM 
 The laboratory testing program was developed to investigate the use of self-
consolidating concrete as a viable material to be used in drilled shaft construction.  This 
research was separated into five separate phases to evaluate or compare an aspect of the 
concrete?s performance.  In this research project the following five phases were 
evaluated: 
? Effect of Type and Dosage of HRWRA 
? Effect of Retarder Dosage 
? Appropriate SCC Mixing Procedure 
? Selection of SCC Properties  
? Methods to Modify the Viscosity of SCC Mixtures 
 
 
 91
4.3.1 Phase I ? Effect of Type and Dosage of HRWRA 
 In view of the fact that the recommended concrete mixture will eventually be used 
for a full-scale field study, it is essential to assess the effect of continuous mixing 
imposed by a ready mix truck during transportation.  Experience has indicated the slump 
or slump flow will decrease with continuous mixing.  Therefore, the primary objective of 
Phase I was to determine the type and approximate dosage of high-range water reducing 
admixture (HRWR) required to produce the necessary slump flow characteristics 
following some period of mixing time.   
    Preliminary investigations indicated that the approximate transportation time 
from the batch plant located in Marion, South Carolina to the proposed field site located 
1.25 miles southeast of Nichols, South Carolina would be approximately 30 minutes.  
Upon arrival at the field site, the slump flow should be within the quality control limits of 
18 to 24 inches with a VSI rating of 1 or less.  Batch sizes of two cubic feet with the 
mixture proportions shown in Table 4.1 were utilized for this phase of the research.  A 
slump flow test was performed on each concrete mixture directly after the completion of 
the mixing procedure, which would represent the slump flow at the batch plant.  The 
concrete mixture would subsequently be mixed for an additional 30 minutes to simulate 
the transportation time.  Afterwards, the slump flow test was performed once more, 
which represented the slump flow at the job site.  Figure 4.1 shows the flow chart used 
for Phase I of this research project.  
 
 
 
 92
Table 4.1 - Concrete Mixture Proportions for Phase I 
 
Item
Coarse Aggregate (No. 67) (lb/yd
3
) 
Coarse Aggregate (No. 789) (lb/yd
3
) 
Fine Aggregate (lb/yd
3
) 
Water (lb/yd
3
) 
Type I Cement (lb/yd
3
) 
Class F Fly Ash (lb/yd
3
) 
Target Air (%)
High-Range Water Reducer (PCE) (oz/cwt)
Retarder (oz/cwt)
Viscosity Modifying Admixture (oz/cwt)
306
500
250
SCC Mixture
1082
394
1366
2
2
8
8 to 12
 
 
 
 
 93
PHASE I 
 
 
Effect of Type and Dosage of High Range Water Reducer 
 
 
2.0 Cubic Feet Batch Size 
 
 
 
          8 oz/cwt Glenium 3030 NS       8 oz/cwt Glenium 3000 NS      10 oz/cwt Glenium 3030 NS       12 oz/cwt Glenium 3030 NS 
 
 
 
 
 
 
Fresh Properties 
 
Slump Flow 
 
Plant 
 
Job Site  
 
 
 
 
 
Figure 4.1 ? Flow chart for Phase I
 94
94 
4.3.2 Phase II ? Effect of Retarder Dosage 
When tremie placement or temporary casing is utilized for drilled shaft 
foundations it is not only important to have sufficient workability initially, but it is also 
critical to maintain the workability for the duration of the pour.  Controlled setting of the 
concrete mixture is necessary to allow for any construction delays in concreting, and to 
allow the temporary casing to be removed after concreting is completed.  In most cases, 
retarding admixtures are used to provide the controlled setting that is necessary to 
complete the construction sequence.   
The primary objective of Phase II was to determine the effect of retarding 
admixtures on the retained workability over some duration of time.  Batch sizes of two 
cubic feet with the mixture proportions shown in Table 4.2 were used for this phase of 
the research project.  Therefore, only the effect of the delayed hydration due to the 
retarder dosage was examined in the phase.  Slump flow tests were performed over time 
as well as setting tests for each batch.  Figure 4.2 shows the flow chart used for this phase 
of the research project.   
           Table 4.2 - Concrete Mixture Proportions for Phase II 
 
 
Item
Coarse Aggregate (No. 67) (lb/yd
3
) 
Coarse Aggregate (No. 789) (lb/yd
3
) 
Fine Aggregate (lb/yd
3
) 
Water (lb/yd
3
) 
Type I Cement (lb/yd
3
) 
Class F Fly Ash (lb/yd
3
) 
Target Air (%)
Retarder (oz/cwt)
High-Range Water Reducer (PCE) (oz/cwt)
Viscosity Modifying Admixture (oz/cwt)
SCC Mixture
1082
394
250
2
1366
306
500
10
2
0 to 8
95
Figure 4.2 ? Flow chart for Phase II
 96
PHASE II  
 
 
Effect of Retarding Admixture 
 
 
2.0 Cubic Feet Batch Size 
 
 
 
                        0 oz/cwt Retarder                                         4 oz/cwt Retarder                                    8 oz/cwt Retarder 
 
 
 
 
 
Fresh Properties 
 
Slump Flow 
 
Plant 
 
Job Site  
 
Retention 
 
Time of Set 
96 
4.3.3 Phase III ? Appropriate SCC Mixing Procedure 
The purpose of Phase III was to determine an appropriate SCC mixing procedure 
to be used throughout the remaining research project as well as the field study.  It should 
be noted that the standardized mixing procedure provided by ASTM C 192 (1998) is not 
appropriate for SCC.  Two suggestions were provided by either chemical admixture 
representatives or ready mix concrete suppliers as to when the HRWR admixture should 
be added.  One suggestion indicated that adding the HRWR admixture before the addition 
of the cementitious materials may improve the effectiveness of the HRWR admixture.  
The other suggestion preferred that the HRWR admixture be added after the addition of 
the cementitious materials so that a ?water slump? can be obtained.  The purpose of this 
water slump is to give an indication of the concrete?s consistency due to the net mixing 
water alone.  Furthermore, the water slump can be an indicator to determine if the 
moisture corrections performed on the aggregate was correct.  Thus, two mixing 
procedures were developed to determine the effect of timing of HRWR admixture 
addition.  Batch sizes of two cubic feet with the mixture proportions shown in Table 4.3 
were mixed according to the mixing procedures listed below.  In addition, slump flow 
tests were performed over time to determine the effect of the mixing process on the 
slump flow retention.  Figure 4.3 shows the flow chart used for this phase of the project.   
 
 
 
 
 
 97
                  Table 4.3 ? Concrete Mixture Proportions for Phase III 
 
Item
Coarse Aggregate (No. 67) (lb/yd
3
) 
Coarse Aggregate (No. 789) (lb/yd
3
) 
Fine Aggregate (lb/yd
3
) 
Water (lb/yd
3
) 
Type I Cement (lb/yd
3
) 
Class F Fly Ash (lb/yd
3
) 
Target Air (%)
Retarder (oz/cwt)
Viscosity Modifying Admixture (oz/cwt)
2
2
8
SCC Mixture
1082
394
1366
306
500
250
 
 
 
 
 
 
 
 
Mixing Procedure 1 ? Early Addition of HRWRA 
1. Add 50% of mixing water into the concrete mixer. 
2. Add coarse and fine aggregates. 
3. Add any retarding admixtures onto aggregates. 
4. Mix for 1 minute. 
5. Add the rest of the mixing water. 
6. Add HRWR while concrete is mixing. 
7. Mix for 2 minutes. 
8. Stop the mixer and add cementitious materials. 
9. Add any VMA while concrete is mixing. 
10. Run the mixer for 3 minutes. 
11. Rest for 3 minutes. 
12. Run the mixer for an additional 2 minutes. 
13. Stop the mixer and take a slump or slump flow reading.  This represents testing at 
the batch plant. 
14. Run the mixer for 50 minutes.  This accounts for transportation time that will be 
required. 
 98
15. Stop the mixer and take a slump or slump flow reading.  This represents the 
testing at the job site. 
16. Proceed to make all fresh and hardened specimens for testing.  
 
Mixing Procedure 2 ? Delayed Addition of HRWRA 
1. Add 80% of the mixing water into the mixer. 
2. Place the coarse and fine aggregate into the mixer. 
3. Add any retarding admixtures onto aggregates.   
4. Mix for 1 minute. 
5. Stop the mixer and add cementitious materials. 
6. Add the rest of the mixing water. 
7. Add any VMA while the concrete is mixing. 
8. Mix concrete for 2 minutes. 
9. Stop the mixer and take a water slump reading. 
10. Add any water reducing admixtures. 
11. Run the mixer for 3 minutes.  
12. Rest for 3 minutes. 
13. Run the mixer for an additional 2 minutes. 
14. Stop the mixer and take a slump or slump flow reading.  This represents testing at 
the batch plant. 
15. Run the mixer for an additional 50 minutes.  This accounts for the transportation 
time that will be required. 
16. Stop the mixer and take a slump or slump flow reading.  This represents testing at 
the job site. 
17. Proceed to make all fresh and hardened concrete specimens for testing.  
 
 
 99
 
 
Figure 4.3 ? Flow chart for Phase III 
 100
 
PHASE III 
 
 
Effect of Timing of High Range Water Addition 
 
 
2.0 Cubic Feet Batch Size 
 
 
 
 
                                 Mixing Procedure 1                                                             Mixing Procedure 2 
 
 
 
 
 
 
Fresh Properties 
 
Slump Flow 
 
Plant 
 
Job Site  
 
Retention 
 
 
100 
4.3.4 Phase IV ? Selection of SCC Properties  
Phase IV can be considered the most important component and primary focus of 
this research project.  It was determined that the most influential parameters that would 
affect the fresh and hardened properties of self-consolidating concrete compared to 
ordinary drilled shaft concrete were the sand-to-aggregate ratio, water-to-cementitious 
materials ratio, and the use of various type of supplementary cementitious materials.  As 
a result, these were the factors selected to be varied for the SCC mixtures within this 
phase of the research.  This phase of the research project will not only examine different 
aspects of self-consolidating concrete (SCC) using various mixtures, but will also 
compare the fresh and hardened concrete properties of SCC and ordinary drilled shaft 
concrete (ODSC).  Figure 4.6 shows the flow chart used for this phase of the project.   
There were a total of nine different concrete batches prepared for Phase IV.  All 
of these mixtures were made from materials obtained from South Carolina that will most 
likely be used during the field project.  Two of the concrete mixtures were of ODSC, 
while the other seven were various SCC mixtures.  Table 4.4 presents the mixture 
proportions and dosages of chemical mixtures used for each concrete mixture.  One 
important point that needs to be considered is that the two ordinary drilled shaft concrete 
mixtures were not designed by the researcher or the research advisors, rather these 
concrete mixtures were provided by a ready mix concrete supplier in South Carolina.  It 
was expressed that these concrete mixtures met all requirements for wet-hole 
construction in South Carolina and are routinely accepted by the South Carolina 
Department of Transportation (SCDOT) for drilled shaft construction.  The use of the two 
ordinary drilled shaft mixtures will not only provide a means of evaluating the 
 101
differences between ordinary drilled shaft concrete and self-consolidating concrete for 
both fresh and hardened properties, but also assist in the decision of which SCC mixture 
will be suitable for further evaluation during the construction of full-scale shafts in South 
Carolina.  
 A specific identification system for this phase was developed to clearly 
distinguish each mixture and assist in logging of the test results.  The identification 
system for the ordinary drilled shaft concrete consisted of the mix number followed by 
ODSC as shown below. 
1:ODSC
Mix Number Ordinary Drilled Shaft Concrete
  
 
 
Figure 4.4 ? Example of Identification System for Ordinary Drilled Shaft Concrete 
 
The identification system for the SCC mixtures is slightly more complex due to the fact 
that there are more mixtures with greater discrepancies.  The identification system for the 
SCC mixtures was named in order of the mix number, water-to-cementitious materials 
ratio, sand-to-aggregate ratio, and supplementary cementitious material type.  For 
example, a SCC mixture with the identity 3:41-48-FA would be the third mixture with a 
water-to-cementitious materials ratio of 0.41, sand-to-aggregate ratio of 0.48, and 
comprised of fly ash (FA) as the supplementary cementing material.  
 
3:41-48-FA
Mix Number
Water-to-Cementitious Ratio
Sand-to-Aggregate Ratio
Supplementary Cementing Material
 
 
 
 
Figure 4.5 ? Example of Identification System for SCC Mixtures 
 102
103 
  Table 4.4 - Concrete Mixture Proportions for Phase IV 
 
 
 
 103
Item 1:ODCS 2:ODCS 3:41-48-FA 4:41-44-FA 5:41-40-FA 6:36-40-FA 7:36-40-SG 8:36-40-SF 9:36-44-FA
Coarse Aggregate (No. 67) (lb/yd
3
) 1458 1778 1082 1191 1304 1300 1326 1286 1208
Coarse Aggregate (No. 789) (lb/yd
3
) 320 0 394 434 460 463 478 470 442
Fine Aggregate (lb/yd
3
) 1181 1181 1366 1285 1190 1175 1195 1164 1289
Water (lb/yd
3
) 289 289 306 293 284 270 270 270 270
Type I Cement (lb/yd
3
) 560 560 500 477 465 500 450 442 500
Class F Fly Ash (lb/yd
3
) 140 140 250 238 230 250 0 248 250
GGBF Slag (lb/yd
3
) 0000003000
Silica Fume (lb/yd
3
) 0000000600
Target Air (%) 2 2 2 2 2 2 2 2 2
Mid-Range Water Rducer (NP) (oz/cwt) 880000000
Mid-Range Water Rducer (PCE) (oz/cwt) 000004444
High-Range Water Reducer (PCE) (oz/cwt) 0 0 10 10 10 10 12 12.5 10
Retarde (oz/cwt) 448888121210
Viscosity Modifying Admixture (oz/cwt) 0 0 2 2 2 2 0 0 2
Water-to-Cementitious Materials Ratio 0.41 0.41 0.41 0.41 0.41 0.36 0.36 0.36 0.36
Sand-to-Aggregate Ratio 0.40 0.40 0.48 0.44 0.40 0.40 0.40 0.40 0.44
Agregat Volume Fraction (% By Volume) 676764656666676666
Paste Volume Fraction (% By Volume) 141416151516151616
Ordinary DSC Self-Consolidating Concrete Mixtures
A batch size of 6.5 ft
3 
was utilized for the ordinary drilled shaft concrete mixtures 
and 8.0 ft
3
 for SCC mixtures.  These batch sizes were established based on the required 
volume of concrete to perform all fresh and hardened concrete tests with the addition of 
20% extra volume for waste.  The following is a list of the fresh and hardened concrete 
properties to be tested as well as some specific requirements for this phase of the 
research.  
A. Fresh Concrete Properties
1.  Slump Test  ASTM C 143 (1998) 
a. Performed on all ordinary drilled shaft concrete mixtures directly after mixing 
and at the time of placement  
b. Performed on all SCC mixtures directly before the addition of the high-range 
water reducing admixture  
c. Performed periodically on all ordinary drill shaft concrete mixtures for a 
duration of no less than 5 hours after batching (slump retention) 
2. Slump Flow Test   
a. Performed on SCC mixtures directly after mixing and at time of placement  
b. Performed periodically on all self-consolidating concrete mixtures for a 
duration of no less than 5 hours after batching (slump flow retention) 
3. Total Air Content and Unit Weight ASTM C 138 (1998) 
a. Performed on all concrete mixtures  
4. L-Box Test 
a. Performed on all SCC mixtures at time of placement  
5. J-Ring Test  
a. Performed on all SCC mixtures at time of placement  
6. Segregation Column  
a. Performed on all SCC mixtures at time of placement  
 
 
 
 104
7. Bleeding Test ASTM C 232 (1998)  
a. Performed on all concrete mixtures 
b. Performed until bleeding of the concrete mixtures has seized  
8.  Setting by Penetration Resistance ASTM C 403 (1998) 
a. Performed on all concrete mixtures  
b. 6 x 6 inch cylindrical specimens of mortar obtained by wet sieving  
 
B. Hardened Concrete Properties   
1.  Compressive Strength ASTM C 39 (1998) and Elastic Modulus ASTM C 469 
(1998) 
a. 6 x 12  inch cylindrical specimens  
b.  Test 3 cylinders at ages of 3, 7, 14, 28, and 56 days 
2.  Drying Shrinkage ASTM C 157 (1998) 
a.  3 concrete prisms 3 x 3 x 12 inch 
b. Test at ages 1, 2, 3, 7, 14, 28, 56, 91, 180, and 365 days after curing  
3. Permeability ASTM C 1202 (1998) 
a. 4 x 8 inch cylindrical specimens  
b. Test 3 specimens at ages of 91 and 365 days 
 
C. Requirements  
1. The slump of the ordinary drilled shaft concrete mixtures, at the time of 
placement, shall be 8 ? 1 inches. 
2. The slump flow of the SCC mixtures, at the time of placement, shall be 21 ? 3 
inches. 
3. A 28-day required compressive strength (f
cr
?) of 5,200 psi is needed. 
4. No segregation of the concrete mixtures may occur at time of placement.  The 
visual stability index (VSI) of the SCC mixtures, at the time of placement, shall 
be 1.0 or less.  
 
 105
PHASE IV
 
 
 
Ordinary Drilled Shaft Concrete                                                                Self-Consolidating Concrete 
 
 
 
 
 
 
                                                                         Effect of Sand-to-Aggregate Ratio         Effect of Water-to-Cementitious Ratio 
                                                                    Sand-to-Aggregate Ratio = 0.48                    Water-to-Cement Ratio = 0.41 
                                                                    Sand-to-Aggregate Ratio = 0.44                    Water-to-Cement Ratio = 0.36 
                                                                                  Sand-to-Aggregate Ratio = 0.40 
 
 
 
 
 
 
             Fresh Properties                                                                                       Fresh Properties  
 
 Slump                                                                                  Slump Flow 
                  Batch Plant                                                                                  Batch Plant 
                    Job Site                                                                                   Job Site 
                   Retention                                                                                  Retention 
                   Bleeding                                                                                     Passing Ability  
                     Setting                                                                                    Segregation  
                                                                       Bleeding 
                                                                       Setting 
 
Figure 4.6 ? Flow Chart for Phase IV (continued on next page) 
 
 106
106 
 
 
 
            Hardened Properties                                                                               Hardened Properties 
 
            Strength Development                                                                            Strength Development  
             Modulus of Elasticity                                                                    Modulus of Elasticity 
               Drying Shrinkage                                                                                    Drying Shrinkage 
                   Permeability                                                                                            Permeability 
                  
 
 
 
 
 
 
 
                                                                              Comparison 
 
                                                              Ordinary Drilled Shaft Concrete 
 
                                                                 Self-Consolidating Concrete 
 
 
 
 
 
Figure 4.6 ? Flow Chart for Phase IV
 107
107 
4.3.5 Phase V ? Methods to Modify the Viscosity of SCC Mixtures  
Phase V will examine the various methods to modify the viscosity of a SCC 
mixture.  There were a total of 21 different concrete batches prepared for Phase V.  Each 
batch was designed to evaluate a distinct method of modifying the viscosity as identified 
during the literature review of this research project.  These methods included one or more 
of the following: reduction in water-to-cementitious materials ratio, change in type of 
supplementary cementing material, and/or VMA dosage.  The sand-to-aggregate was held 
constant at 0.40 for all concrete batches; therefore, only the effect of the different 
viscosity modifiers will be examined.  It was determined that a sand-to-aggregate ratio of 
0.40 would be the worst case scenario for not only increasing the viscosity of a concrete 
mixture, but also increasing the stability of the mixture at higher slump flows.  Table 4.5 
presents the appropriate mixture proportions and approximate dosages of chemical 
mixtures used for each concrete mixture.   
  The identification system for the SCC mixtures was named in order of the mix 
number, material source, water-to-cementitious materials ratio, and viscosity modifying 
method.  For example, a SCC mixture with the identity 6:AL-36-33 FA would be the 
sixth mixture with the materials being from a local source in Alabama, water-to-
cementitious materials ratio of 0.36, and comprised of 33% fly ash as the viscosity 
modifying method.  
 
 
 
 
3:AL-36-33 FA
Mix Number
Water-to-Cementitious Ratio
Material Source
Viscosity Modifier 
Figure 4.7 ? Example of Identification System for Phase V 
 108
A batch size of 3 ft
3
 was established based on the required volume of concrete to 
perform all fresh and hardened concrete tests with the addition of 20% extra volume for 
waste for all SCC mixtures.  The following is a list of the fresh and hardened concrete 
properties to be tested as well as some specific requirements for this phase of the 
research.  Figure 4.8 illustrates the flow chart used for this phase of the project.   
A. Fresh Concrete Properties
1. Slump Flow Test   
a. Performed on SCC mixtures directly after mixing and at time of placement  
2. Total Air Content and Unit Weight ASTM C 138 (1998) 
 
B. Hardened Concrete Properties   
1.  Compressive Strength ASTM C 39 (1998) and Elastic Modulus ASTM C 469 
(1998) 
a. 6 x 12  inch cylindrical specimens  
b. Test 3 cylinders at ages of  7, 28, and 56 days 
 
C. Requirements  
1. The slump flow of the SCC mixtures, at the time of placement, shall be 21 ? 3 
inches. 
2. A 28-day required compressive strength (f
cr
?) of 5,200 psi is needed. 
3. No segregation of the concrete mixtures may occur at time of placement.  The 
visual stability index (VSI) of the SCC mixtures, at the time of placement, shall 
be 1.0 or less.  
 109
110 
             Table 4.5 - Concrete Mixture Proportions for Phase V 
 
110
ITEM
Self-Consolidating 
Concrete Mixtures
C
oar
s
e
 A
ggr
ega
t
e
 (
N
o.
 67)
 
(
l
b/
yd
3
) 
C
o
a
r
s
e
 
A
g
g
r
eg
a
t
e
 
(
N
o
.
 
8
9
)
 
(
l
b
/
y
d
3
)
 
Fi
n
e
 A
g
g
r
egat
e 
(
l
b/
y
d
3
) 
W
a
te
r (l
b
/
y
d
3
) 
Ty
pe I
 
C
e
m
e
nt
 (
l
b/
y
d
3
) 
C
l
ass
 
F Fl
y A
s
h 
(
l
b/
yd
3
) 
G
G
B
F
 S
l
ag 
(
l
b/
yd
3
) 
S
i
l
i
ca
 Fu
m
e
 
(
l
b
/
yd
3
) 
M
i
c
r
on
 3 
(
l
b/
y
d
3
) 
Li
m
e
 s
t
one
 (
l
b
/
y
d
3
) 
 T
a
rg
e
t
 
A
i
r (%
)
M
i
d-
R
a
nge W
a
t
e
r
 R
edu
c
e
r
 
(
P
C
E
)
 
(
o
z/
cw
t
)
H
i
gh
-
R
ange
 W
a
t
e
r
 R
e
duc
er
 
(
P
C
E
)
 
(o
z
/
c
w
t)
R
e
ta
rd
e
r
 (o
z
/
c
w
t)
V
i
s
c
o
s
i
t
y
 M
odi
f
y
i
n
g A
d
m
i
x
t
ur
e 
(
o
z/
cw
t
)
W
a
t
e
r
-
t
o-
C
e
m
ent
i
t
i
ous
 M
a
t
e
r
i
al
s
 
Ra
t
i
o
S
and
-
t
o-
A
g
g
r
egat
e R
a
t
i
o
A
g
gr
egat
e V
o
l
u
m
e
 Fr
a
c
t
i
o
n
 
(
%
 B
y
 
Vo
l
u
me
)
P
a
st
e V
o
l
u
m
e
 Fr
ac
t
i
o
n
 
(
%
 B
y
 
Vo
l
u
me
)
1:AL-41-0 VMA 1304631828446523000002010800.410.406 15
2:Al-41-2 VMA 1304631828446523000002010820.410.406 15
3:AL-41-10 VMA 13046318284465230000020108100.410.406 15
4:AL-41-18 VMA 13046318284465230000020108180.410.406 15
5:AL-36-33?2FA 12834611922705025000002410820.360.406 16
6:AL-36-33 FA 126445014828452926000002010800.360.406417
7:AL-36-40 FA 124645015028447331500002010800.360.406417
8:AL-36-50 FA 12045015028439439500002010800.360.406318
9:AL-36-6 SF 125470158284497245047002012800.360.406417
10:AL-36-8 SF 123546015284486239063002013800.360.406417
11:AL-36-10 SF 12346015284475234079002013800.360.406417
12:AL-36-15 SF 1284501602844921018002015800.360.406417
13:AL-36-40 SG 130478182704500300002012800.360.406715
14:AL-36-50 SG 13046815028439403950002012800.360.406 15
14:AL-36-50 SG (LA) 1303 468 1150 284 394 0 395 0 0 0 2 20 0 8 0 0.36 0.40 66 15
15:AL-36-60 SG 12947015428431604730002012800.360.406 16
16:AL-36-8 M3 1252 452 1148 284 465 260 0 0 63 0 2 0 10 8 0 0.36 0.40 64 17
17:AL-36-12 M3 1245 452 1148 284 435 260 0 0 94 0 2 0 10 8 0 0.36 0.40 64 17
18:AL-36-16 M3 1244 448 1148 284 403 260 0 0 126 0 2 0 10 8 0 0.36 0.40 64 17
19:AL-36-8 LS 1285 470 1173 270 442 248 0 0 0 60 2 0 10 8 0 0.36 0.40 66 16
20:AL-36-15 LS 1289 465 1168 270 389 248 0 0 0 112 2 0 10 8 0 0.36 0.40 66 16
21:AL-36-20 LS 1275 461 1180 270 352 248 0 0 0 150 2 0 10 8 0 0.36 0.40 66 16
 
 
 
Figure 4.8 ? Flow Chart for Phase V
 111
PHASE V 
 
 
Effect of Viscosity Modifier Type 
 
 
3.0 Cubic Feet Batch Size 
 
 
 
              VMA             Fly Ash           Silica Fume            Slag           Micron 3       Limestone       Water-to-Cementitious Ratio 
        
 
 
 
Fresh Properties 
 
Slump Flow 
Plant 
Job Site  
 
 
                                                                                          Hardened Properties  
 
Strength Development  
 
Modulus of Elasticity 
111 
4.4 RAW MATERIAL SOURCES  
 Section 4.4 will present the raw materials that were used for this research 
program.  The material part is separated into three separate subsections.  These 
subsections include cementitious materials, aggregates, and chemical admixtures.  Two 
sources of aggregates, two different cement sources, and two different sources of fly ash 
were used in this research.  One source of cement, fly ash, and aggregates was imported 
from South Carolina, which was used for Phases I through IV.  Phase V incorporated 
another source of cement, fly ash, and aggregates that was obtained from a local source 
located in Alabama.  It is important to mention that the raw materials from Alabama were 
carefully selected to match, as closely as possible, that of the imported raw materials 
from South Carolina.  Due to the limited amount of South Carolina material, it was not 
feasible to consume the South Carolina material for Phase V since it was not the primary 
focus of this research.  However, closely matching the material sources allowed any 
valuable information obtained from Phase V to be easily transferable to the South 
Carolina materials.  As a result of this exercise, some mix designs were obtained from 
Phase V and incorporated in Phase IV using South Carolina materials.   
4.4.1 Cementitious Materials 
? Type I Portland Cement: There were two different sources of cement used for this 
research project.  The first source of Type I cement was manufactured by Giant 
Cement Company located in Harleyville, South Carolina.  The Giant Type I 
cement was utilized for Phases I through IV of this research project.  The 
chemical analysis was performed by Analytical Laboratories, Inc.  Table 4.6 
presents the chemical analysis results performed on this brand of cement.  
 112
Furthermore, the Giant Type I cement had a Blaine Fineness of 367 m
2
/kg as 
determined by ASTM C 204 (1998).  The second source of Type I cement was 
manufactured by Lafarge Cement, Inc.  The Lafarge cement was exclusively 
utilized for Phase V.  In addition, the Lafarge Type I cement had a Blaine 
Fineness of 398 m
2
/kg as determined by ASTM C 204 (1998).   
                   Table 4 I Cement 
 
 
.6 ? Chemical Analysis Results for the Giant Type 
  
 
 
? Class F Fly Ash
 
: As with the cement, there were two main sources of Class F fly 
ash.  One source of Class F fly ash was provided by the SEFA Group in Wateree, 
South Carolina.  The SEFA Group fly ash was utilized for Phases I through IV.  
Item % by Weight
Silicon Dioxide, SiO
2
20.46
Aluminum Oxide, Al
2
O
3
4.78
Iron Oxide, Fe
2
O
3
3.54
Calicum Oxide, CaO 65.28
Magnesium Oxide, MgO 1.31
Sodium Oxide, Na
2
O 0.08
Potassium Oxide, K
2
O 0.1
Total Alkalies as Na
2
O 0.14
Titanium Dioxide, TiO
2
0.37
Manganic Oxide, Mn
2
O
3
0.04
Phosphorus Pentoxide, P
2
O
5
0.1
Strontium Oxide, SrO 0.08
Barium Oxide, BaO 0.03
Sulfur Trioxide, SO
3
2.57
Tricalcium Silicate, C
3
S 65.76
Tricalcium Aluminate, C
3
A 6.69
Dicalcium Silicate, C
2
S 9.03
Tetracalcium Aluminoferrite, C
4
AF 10.77
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 113
Table 4.7 shows the results of the chemical analysis on this brand of fly ash as 
performed by Analytical Laboratories, Inc.  The second source of fly ash was 
manufactured by Boral Material Technologies.  This brand of fly ash cement was
exclusively used for Phase V.   
   Table 4.7 ? Chemical Analysis Results for the SEFA Group Class F Fly Ash 
 
 
       
Iron Oxide, Fe
2
O
3
9.06
Calicum Oxide, CaO 1.7
Magnesium Oxide, MgO 0.94
Sodium Oxide, Na
2
O 0.6
Potassium Oxide, K
2
O 2.58
Titanium Dioxide, TiO
2
1.52
Manganese Oxide, MnO
2
0.05
Phosphorus Pentoxide, P
2
O
5
0.37
Strontium Oxide, SrO 0.14
Barium Oxide, BaO 0.19
Sulfur Trioxide, SO
3
0.24
Item % by Weight
Silicon Dioxide, SiO
2
52.19
Aluminum Oxide, Al
2
O
3
27.83
 
 
? Ground Granulated Blast Furnace Slag (GGBFS): The GGBFS used throughout 
this entire research project was provided by Buzzi Unicem USA, Inc.  This slag 
meets specifications set forth by ASTM C 989 (1998) for a Grade 120 Ground 
? 
Granulated Blast Furnace Slag.   
Condensed Silica Fume: The silica fume used in this research project was 
manufactured by Simicala, Inc. located in Mt. Meigs, Alabama.   
 114
Limestone Filler: The limestone filler used in this research project was provided
by Sanco, Inc. at their plant in Da
?  
lton, Georgia.  It is important to note that 
r, it is 
 the binder 
? 
limestone filler is an inert filler rather than cementitious material.  Howeve
best to introduce the limestone filler at this point since it is part of
content.   
Micron 3:  The Micron 3, or commonly know as ultra fine fly ash, used in th
research project was provided by Boral Material Technologies, Courtesy of Mr. 
Russel Hill.  Table 4.8 presents the chemical analysis results for the Micron 3
is 
.   
 
 
 
 
The particle size d cluding the 
mestone filler was determined by a laser particle size analyzer at the Alabama 
epartment of Transportation as shown in Figure 4.9.  The particle size distribution 
49.21
26.71
80.54
11.72
2.07
1.36
0.48
1.12
1.22
0.30
Magnesium Oxide, (MgO)
Silicon Dioxide, (SiO
2
)
Aluminum Oxide, (Al
2
O
3
),
Available Alkalies, (as Na
2
O)
Sulfur Trioxide, (SO
3
)
Sodium Oxide, (Na
2
O) 
Potassium Oxide, (K
2
O)
Total Alkalies, (as Na
2
O)
Sum of SiO
2
, Al
2
O
3
, Fe
2
O
3
Calcium Oxide, (CaO),
Table 4.8 ? Chemical Analysis Results for the Micron 3 Fly Ash 
 
Item % by Weight
 
4.62
Iron Oxide, (Fe
2
O
3
)
 
 
 
 
 
istribution for all cementitious materials in
li
D
 115
results are illustrated on Figure 4.10.  It is important to note that all materials were tested 
and ana on, the 
n its 
 
lyzed in a dry condition.  Since the silica fume was tested in a dry conditi
laser particle size analyzer tested the silica fume in its condensed state rather tha
individual particles.  As a result, the data on Figure 4.10 indicates that the silica fume
produced one of the largest particle size distributions.  However, if the silica fume was 
tested in a non-condensed state the particle size distribution would be significantly 
smaller.  Table 4.9 presents the specific gravities for the cementitious materials and 
limestone filler used throughout this research project.    
 
                         Table 4.9 ? Specific Gravities for Cementitious Materials  
 
Raw Material Specific Gravity 
Giant Type I Cement 3.15
SEFA Class F Fly Ash 2.28
Boral Class F Fly Ash 2.28
Boral Micron 3 Class F Fly Ash 2.58
GGBFS 2.93
Silica Fume 2.30
Limestone Filler 2.71
Lafarge Type I Cement 3.15
 116
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
Figure 4.9 ? Particle Size Analyzer
 117
117 
Figure 4.10 ? Laser Particle Size Analyzer Results 
 118
0
1
2
3
4
5
6
0.1 1 10 100 1000
Particle Size (?m)
Vo
lu
m
e
 (
%
)
Lafarge Type 1 Giant Type 1 SEFA Class F Fly Ash Boral Class F Fly Ash
GGBFS Micron 3 Silica Fume  Limestone Filler
118 
4.4.2 Aggregates  
 As previously stated, there were two different aggregate sources used for this 
research project.  One source of aggregate was supplied by the Marlboro Quarry located 
in South Carolina.  The fine and coarse aggregate from South Carolina was placed into 
?super sacs? and delivered to Auburn University by means of a transfer truck as shown in 
Figure 4.11.  The local source of fine and coarse aggregate was supplied by the Shorter 
Plant and stocked by Twin City Concrete.  Both sources of coarse and fine aggregates 
were selected to provide necessary aggregate characteristics needed for this research.  
The nature of river gravel is important because it is composed of particles having a round 
shape that will provide greater workability as compared to crushed gravel.   
 
Figure 4.11 ? Raw Material being Delivered from South Carolina 
 
 119
 The coarse aggregate from the Marlboro Quarry consisted of a No. 67 and No. 
789 gradation while the fine aggregate classified as FA-10 sand.  The coarse aggregate 
from the Shorter Plant consisted of a No. 67 and No. 89 gradation.  It is important to 
mention that this research originally called for the use of a No. 7 gradation for the SCC 
mixtures; however, this gradation could not be supplied by a quarry in South Carolina.  
The No. 7 aggregate was preferred, since it would provide a SCC mixture with higher 
passing ability.  As a result, an aggregate blend comprised of a No.67 and No. 789 was 
developed.  Upon arrival, the aggregates were tested to determine their gradation, 
absorption capacity, and specific gravities.  All aggregates were tested in accordance to 
ASTM C 33 (2002).  Table 4.10 presents the absorption capacities and specific gravities 
(saturated surface dry).  Figures 4.12 through 4.17 show the gradations of the fine and 
coarse aggregates for both sources.   
 
Table 4.10 ? Specific Gravities and Absorption Capacities for Aggregate Sources 
 
Raw Material Absorption Capacity (%) Specific Gravity (SSD)
Fine Aggregate (SC)* 0.5 2.63
Fine Aggregate (AL)** 0.68 2.64
No. 67 River Gravel (SC)* 0.4 2.65
No. 67 River Gravel (AL)** 0.57 2.64
No. 789 River Gravel (SC)* 0.4 2.64
No. 89 River Gravel (AL)** 0.62 2.63
* SC = South Carolina Material 
** AL = Alabama Material 
 
 
 
 
 
 
 
 
 
 
 
 
 
 120
0
10
20
30
40
50
60
70
80
90
100
0.1001.000
Sieve Size
M
ass P
e
r
c
en
t
 
P
assi
n
g
 
ASTM C33 Upper Limit
ASTM C33 Lower Limit
# 67
1"
3/4" 
3/8"
#4
#8
1/2" 
 
Figure 4.12 ? No. 67 Coarse Aggregate Gradation for South Carolina Material 
 
0
10
20
30
40
50
60
70
80
90
100
0.010.11
Sieve Size
M
a
ss P
e
r
c
e
n
t
 P
a
ssi
n
g
 
SCDOT Upper Limit
SCDOT Lower Limit
# 789
1"
1/2" #4
#16
3/8" 3/4"
#100
 
Figure 4.13 ? No. 789 Coarse Aggregate Gradation for South Carolina Material 
 
 121
0
10
20
30
40
50
60
70
80
90
100
0.1001.00010.000
Sieve Size
M
a
ss
 P
e
r
c
en
t
 P
a
ss
i
n
g
 
ASTM C33 Upper Limit
ASTM C33 Lower Limit
 Fine Aggregate
3/8"  #4
 #30 #16 #8  # 50
# 100
 
Figure 4.14 ?Fine Aggregate Gradation for South Carolina Material 
 
 
0
10
20
30
40
50
60
70
80
90
100
0.1001.000
Sieve Size
M
a
ss P
e
r
c
e
n
t
 P
a
ssi
n
g
 
ASTM C33 Upper Limit
ASTM C33 Lower Limit
# 67
1"
3/4" 
3/8"
#4
#8
1/2" 
 
Figure 4.15 ? No. 67 Coarse Aggregate Gradation for Alabama Material 
 
 
 122
0
10
20
30
40
50
60
70
80
90
100
0.010.11
Sieve Size
M
a
ss
 P
e
r
c
en
t
 
P
a
ss
i
n
g
 
ASTM C33 Upper Limit
ASTM C33 Lower Limit
# 89
1" 1/2" #4 #163/8" #8 #50
 
Figure 4.16 ? No. 89 Coarse Aggregate Gradation for Alabama Material 
 
0
10
20
30
40
50
60
70
80
90
100
0.1001.00010.000
Sieve Size
M
a
s
s
 Pe
r
c
e
n
t
 
Pa
s
s
in
g
 
ASTM C33 Upper Limit
ASTM C33 Lower Limit
 Fine Aggregate
3/8"  #4
 #30 #16 #8  # 50
# 100
 
Figure 4.17 ?Fine Aggregate Gradation for Alabama Material 
 
 
 
 
 123
4.4.3 Chemical Admixtures  
 
? Supplier: All chemical admixtures were provided by Degussa Admixtures, Inc., 
which was formally known as Master Builders Technologies.   
? Mid-Range Water Reducing Admixture (MRWRA): There were two main types 
of mid-range water reducing admixtures used for this research project.  The first 
type of MRWR admixture was PolyHeed N, which was only used for the ordinary 
drilled shaft concrete mixtures.  This admixture was not selected by the researcher 
or the research advisors, instead this admixture type and dosage was provided by 
a ready mix concrete supplier as described early in Section 4.3.4.  PolyHeed N is 
a chloride bearing mid-range water reducing admixture that meets requirements 
set forth by ASTM C 494 (1998) for a Type A water reducing admixture.  The 
second type of MRWR admixture used in this research was PolyHeed 1025.  This 
type of MRWR admixture is based on polycarboxylate ester (PCE) technology 
that meets requirements set forth by ASTM C 494 (1998) for a Type A water 
reducing as well as a Type F high-range water reducing admixture.   
? High-Range Water Reducing Admixture (HRWRA): The HRWR admixtures used 
for this research project were Glenium 3000 NS and Glenium 3030 NS.  Glenium 
3000 NS was only utilized for Phase I of the research project.  Glenium 3030 NS 
was used for Phases I through V.  This type of HRWR admixture is a chemical 
admixture based on polycarboxylate ester (PCE) technology.  Glenium 3000 NS 
and 3030 NS meets requirements set forth by ASTM C 494 (1998) for a Type F 
high-range water reducing admixture.  
 124
? Retarding Admixtures: There were two main types of retarding admixtures used 
for this research project.  The first type of retarding admixture was Pozzolith 100 
XR, which was only used for the ordinary drilled shaft concrete mixtures.  This 
admixture was not selected by the researcher or the research advisors, instead this 
admixture type and dosage was provided by a ready mix concrete supplier as 
described early in Section 4.3.4.  Pozzolith 100 XR meets requirements set forth 
by ASTM C 494 (1998) for a Type B retarding and Type D water reducing and 
retarding admixture.  The second type of retarding admixture utilized in this 
research was Delvo Stabilizer.  Delvo Stabilizer meets requirements set forth by 
ASTM C 494 (1998) for a Type B retarding and Type D water reducing and 
retarding admixture.  
? Viscosity Modifying Admixture (VMA): The VMA used in this research project 
was Rheomac 358.  Rheomac 358 is a polyethylene glycol based or ?thickening 
type? viscosity modifying admixture.   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 125
 
 
 
 
CHAPTER 5 
LABORATORY EQUIPMENT, SPECIMENS, AND PROCEDURES  
5.1 INTRODUCTION  
 Before discussing the laboratory equipment, specimens, and procedures it may be 
beneficial to describe in short detail the recently acquired equipment relevant to this 
research obtained by Auburn University.  Prior to the summer of 2003, all concrete 
mixing was completed outside.  The outside environment was subject to ambient 
conditions that produced significant temperature and moisture variations.  A new state of 
the art mixing facility was built inside the Harbert Engineering Center.  The new mixing 
facility consists of an elevated platform with easy access by stairs or ramp, new 12 ft
3
 
concrete mixer, drainage tank, storage area for materials, and moisture corrections area.  
Furthermore, the facility eliminated the temperature and moisture variations associated 
with the outside mixing facility, and it now forms one of the most important components 
of the concrete research conducted at Auburn University.  The new mixing facility is 
shown on Figure 5.1.  The addition of a new 600-kip Forney compression machine, rapid 
chloride permeability cells, compressometer, and length comparator apparatus has 
allowed more accurate measurements to be taken for the assessment of various fresh and 
hardened concrete properties that may affect the concrete?s performance. 
 
 126
 
Figure 5.1 ? New Indoor Mixing Facility 
 
5.2 BATCHING AND MIXING PROCEDURE 
 The batching procedure for this research began by obtaining an estimated weight 
amount of coarse or fine aggregate, which was then carefully placed on a plastic sheet.  
The fine or coarse aggregate was thoroughly mixed using a shovel to ensure that the 
aggregate was of homogeneous moisture content.  The aggregate was then placed into 5 
gallon buckets that were tightly sealed with a lid and moved into the mixing room.  
Afterwards, moisture corrections were conducted by obtaining small samples (300-500g) 
of coarse and fine aggregate, which was then placed in a small microwavable dish.  The 
samples were subsequently placed into a microwave and dried to constant weight using a 
small digital scale.  After the moisture content in the coarse and fine aggregate was 
obtained, the mixing water and aggregate weights were adjusted to account for the 
 127
moisture condition of the aggregates.  The weight of the coarse aggregate, fine aggregate, 
cementitious material, and mixing water was then measured into 5 gallon buckets using a 
balance.  The chemical admixtures were measured and obtained using 10 and 50 cc 
syringes.   
 Before the mixing procedure began, the concrete mixer was prepared using a 
?butter batch?.  The butter batch typically consisted of placing a small amount of cement, 
sand, and water inside the concrete mixer that would thoroughly coat the mixer?s wall.  
The purpose of this exercise was to ensure that no cement or free water would be lost or 
soaked up by the concrete mixer wall.  The 12 ft
3
 concrete mixer that was used for this 
project can be seen in Figure 5.2.  After the preparation of the mixer was complete, the 
following mixing procedure was followed.  This mixing procedure for the SCC mixtures 
was based on results from Phase II of the research project. 
1. Add 80% of the mixing water into the mixer. 
2. Place the coarse and fine aggregate into the mixer. 
3. Add any retarding admixtures.  
4. Mix for 1 minute. 
5. Add cementitious materials. 
6. Add the rest of the mixing water. 
7. Add any VMA while the concrete is mixing. 
8. Mix concrete for 2 minutes. 
9. Stop the mixer and take a water slump reading. 
10. Add any water reducing admixtures. 
11. Run the mixer for 3 minutes.  
12. Rest for 3 minutes. 
13. Run the mixer for an additional 2 minutes. 
14. Stop the mixer and take a slump or slump flow reading.  This represents testing at 
the batch plant. 
 128
15. Run the mixer for an additional 50 minutes.  This accounts for the transportation 
time that will be required. 
16. Stop the mixer and take a slump or slump flow reading.  This represents testing at 
the job site. 
17. Proceed to make all fresh and hardened concrete specimens for testing.  
 
 
Figure 5.2 ? 12 ft
3
 Concrete Mixer used for this Research 
 
5.3 FRESH PROPERTY TESTING  
 The fresh concrete properties tested for this research include the slump test, slump 
flow test, J-Ring test, L-Box test, bleeding test, unit weight, air content, and time of set.  
It is important to observe that the determination of the filling ability of SCC by the slump 
flow test, determination of passing ability of SCC by means of the J-Ring and/or L-Box, 
and determination of segregation resistance by the segregation column test has not yet 
been standardized by organizations such as ASTM.  As a result, it may be useful to 
describe these tests in more detail so that the reader can become familiar with the 
 129
equipment and methodology.  It must be noted that the procedures presented in the 
following sections are only an interim guideline until a fully detailed procedure is 
standardized.   
5.3.1 Slump Test 
 Slump tests were performed on the concrete mixtures via the procedure in ASTM 
C 143 (1998), Standard Test Method for Slump of Hydraulic-Cement Concrete.  The 
purpose of this test is to determine consistency of the concrete mixtures.  All equipment 
used met the requirements of this specification.  The mold, base plate, tape measure, 5/8 
inch tamping rod, funnel, and scoop can be seen in Figure 5.3.  The slump test was 
performed on the SCC mixtures before the addition of superplasticizers.  Therefore, there 
was no modification to this test to account for SCC characteristics.  The slump tests were 
conducted by one technician so that any variability in results could be reduced. 
 
Figure 5.3 ? Testing Equipment for Slump Test 
 
 130
5.3.2 Slump Flow Test 
The slump flow test was performed on all SCC mixtures via the procedure 
recommend by the PCI (2003).  The purpose of this test was to determine the filling 
ability of a SCC mixture in the absence of obstructions, and to provide a measure of 
segregation resistance by assigning a stability rating.  The equipment and procedure 
required to perform the slump flow test are listed below.  Figure 5.4 demonstrates the 
equipment used to perform the slump flow test.  
 
Equipment: 
1. Mold similar to the one required by ASTM C 143 (1998), Standard Test Method 
for Slump of Hydraulic-Cement Concrete 
2. Base plate consisting of a non-absorbing stiff material measuring at least 36 
inches square marked with a concentric circle marking the central location of the 
mold and at least one further circle 20 inches in diameter indicating the T
50
 
location 
3. 5/8 inch tamping rod 
4. Scoop 
5. Tape measure  
6. Funnel  
7. Stop watch 
 
 131
 
Figure 5.4 ? Testing Equipment for Slump Flow Test 
Procedure (PCI 2003): 
1. Moisten all equipment and place on a flat and rigid surface. 
2. After the mixture procedure is complete, sample approximately 0.2 ft
3
 of 
SCC in accordance with ASTM C 172 (1998). 
3. Position the mold, with the base downwards, in the center of the base 
plate. 
4. Place the SCC sample into the mold by means of a bucket and funnel.  The 
mold needs to be kept in position.  
5. Strike off any excess SCC by means of rolling the tamping rod over the 
surface. 
6. Remove any excess SCC around the base of the mold by means of an 
absorbent sponge. 
7. Lift the mold vertically a distance of 12 inches in approximately 5 seconds 
without lateral movement allowing the concrete to flow out freely. 
8. Simultaneously start a stop watch when the cone is lifted, and record the 
time taken for the SCC to reach the 20 inch diameter circle (T
50
 time). 
9. Measure the final diameter of the SCC in two perpendicular directions. 
 132
10. Calculate the average of the two diameters and report the result to the 
nearest ? inch. 
11. After the flow has ceased, assign a stability rating to the SCC mixture 
according to Table 5.1 and Figure 5.5.  
 
          Table 5.1 ? Visual Stability Index (VSI) Rating (Khayat et al. 2004) 
Rating Criteria 
0 No evidence of segregation in slump flow patty, mixer drum, 
or wheelbarrow 
1 No mortar halo in slump flow patty, but some slight bleeding on 
surface of concrete in mixer drum and/or wheelbarrow 
2 
Slight mortar halo (<10mm) in slump flow patty and noticeable 
layer of mortar on surface of testing concrete in mixer drum and 
wheelbarrow 
3 
Clearly segregating by evidence of large mortar halo (>10mm) 
and thick layer of mortar and/or bleed water on surface of testing
concrete in mixer drum or wheelbarrow 
 
 
 
 
 
 
 
 
 
 
 
Figure 5.5 - Visual Stability Index Rating (Degussa Construction Chemicals 2004) 
 133
The slump flow test was frequently performed in the inverted position in conjunction 
with the J-Ring test.  Under these circumstances, the mold was placed on the base plate 
with its 4 inch diameter facing downward.  Furthermore, the slump flow tests were 
conducted by two technicians.  The second technician timed the test while the other lifted 
the mold.  The use of such practice helped reduce the operator error and improve the 
accuracy of the T
50
 times.  
5.3.3 J-Ring Test  
The J-Ring test was performed on the SCC mixtures via the procedure 
recommended by the PCI (2003).  The purpose of this test was to determine the passing 
ability of a SCC mixture by comparing the slump flow diameter to the J-Ring diameter.  
Since the slump flow test was used in conjunction with the J-Ring test, the equipment 
required to perform the J-Ring test is similar to the slump flow test with the addition of 
the J-Ring as shown in Figure 5.6.  The J-Ring apparatus consisted of a rectangular 
section 1 1/8 by 1 inch open steel circular ring that measured approximately 12 inches in 
diameter.  The open steel circular ring was drilled vertically to accept 16-5/8 inch 
diameter reinforcement bars measuring 4 inches in height with a center to center spacing 
of approximately 2 5/16 inches.   
 
 
 
 134
 
 
 
 
 
 
 
Figure 5.6 ? Testing Equipment for J-Ring Test 
Procedure (PCI 2003): 
1. Moisten all equipment and place on a flat and rigid surface. 
2. After the mixture procedure is complete, normally sample approximately 
0.2 ft
3
 of SCC in accordance with ASTM C 172 (1998). 
3. Position the mold, with its 4 inch diameter facing downwards, in the 
center of the base plate. 
4. Place the SCC sample into the mold by means of a bucket. 
5. Strike off any excess SCC by means of rolling the tamping rod over the 
surface. 
6. Remove any excess SCC around the base of the mold by means of an 
absorbent sponge. 
7. Lift the mold vertically a distance of 9 +/- 3 inches in 3 seconds without 
lateral movement allowing the concrete to flow out freely. 
8. Measure the final diameter of the SCC in two perpendicular directions. 
9. Calculate the average of the two diameters and report the result to the 
nearest ? inch. 
 135
10. Conduct the slump test using the inverted method with the provided 
procedure in Section 5.2.2.   
11. Calculate the difference between the J-Ring diameter and the slump flow 
diameter of the companion test. 
12. Assign a passing ability rating according to Table 5.2. 
 
           Table 5.2 - J-Ring Passing Ability Rating (ASTM J-Ring Draft 2004) 
Difference between
Slump Flow  
 and J-Ring Flow 
Passing Ability
Rating 
Remarks 
0 ? X ? 1 inch 0 No visible blocking 
1 < X ? 2 inches 1 Minimal to noticeable blocking
X > 2 inches 2 Noticeable to extreme blocking
 
5.3.4 L-Box Test 
The L-Box test was performed on the SCC mixtures via the procedure 
recommended by the PCI (2003).  The purpose of this test was to determine the passing 
ability of a SCC mixture by determining the extent of blocking by reinforcement.  The 
equipment required to perform the L-Box test is listed below and can be seen in Figure 
5.7 and 5.8.   
Equipment: 
1. L-Box made of non-absorbing material with the dimensions shown in 
Figure 5.7     
2. 5/8 inch tamping rod  
3. Scoop  
4. Tape measure 
 
 
 136
 
                                    Figure 5.7 ? L-Box Dimensions (PCI 2003) 
 
 
 
Figure 5.8 ? Testing Equipment for L-Box Test 
 
 
 
 
 137
Procedure (PCI 2003): 
1. Moisten all equipment and place on flat and rigid surface. 
2. After the mixture procedure is complete, sample approximately 0.5 ft
3
 of 
SCC in accordance with ASTM C 172 (1998). 
3. Ensure that the sliding gate can open freely and then close the gate.  
4. Fill the vertical section of the L-Box with the SCC mixture. 
5. Let the SCC mixture stand for approximately 1 minute. 
6. Strike off any excess SCC by means of rolling the tamping rod over the 
surface.  
7. Lift the gate and allow the SCC mixture to flow into the horizontal 
section. 
8. When the flow has ceased, measure and record the ?H1? and ?H2? 
dimensions, shown in Figure 5.7.  
9. Calculate the blocking ratio, H2/H1. 
5.3.5 Segregation Column Test 
The segregation column test was performed on the SCC mixtures via the 
procedure recommended by an ASTM Segregation Column draft (2004).  The purpose of 
this test was to determine the stability and segregation resistance of a SCC mixture.  The 
equipment required to perform the segregation column test is listed below and can be 
seen in Figure 5.9.  
Equipment:  
1. Balance or scale accurate to 0.1 lb. or to within 0.3% of the test load 
2. Column mold made of schedule 40 PVC pipe measuring 8 inches in 
diameter and 26 inches in height and separated into 4 equal sections each 
measuring 6.5 inches in height 
 138
3. Collection plate made of a non-absorbent material measuring 20 inches 
square containing a semi-circular cut out section in the center measuring 
8.5 inches across 
4. 5/8 inch tamping rod  
5. No. 4 Sieve  
 
 
       Figure 5.9 ? Testing Equipment for Segregation Column Test 
 
Procedure (ASTM Segregation Column Draft 2004): 
1. Assemble and moisten all equipment, then place on flat and rigid surface. 
2. After the mixture procedure is complete, sample approximately 0.8 ft
3
 of 
SCC in accordance with ASTM C 172 (1998). 
 139
3. Immediately fill the column mold in one continuous lift allowing the 
concrete to over fill the top.  
4. Strike off any excess SCC by means of rolling the tamping rod over the 
surface.  
5. Allow the SCC to set for 1 hour.  This time was extended to 1 hour from 
the 20 minute recommendation provided by the ASTM Segregation 
Column draft (2004).  It was expected that due to the extended set times 
for drilled shaft concrete that the segregation would be more pronounced 
after 1 hour.  
6. Place the collection plate around the mold and firmly hold the top section 
of mold while removing the spring clamps. 
7. Screed the SCC onto the collection plate by using a horizontal twisting 
motion of the PVC pipe. 
8. Place the obtained SCC from the collection plate into a No. 4 Sieve.  Wet 
wash the sample leaving only the coarse aggregate on the No. 4 sieve.  
9. Repeat steps 7 and 8 for the bottom section of the column. 
10. Calculate the segregation index using the Equation 5.1 and 5.2. 
                             
MB
TB
CA
CACA
SI
)( ?
=                                              Eq. 5.1 
Where: 
SI is the segregation index,  
CA
T
 is the mass of coarse aggregate in the top section (lbs),  
CA
B
 is the mass of coarse aggregate in the bottom section (lbs), and 
CA
BM
 is the mass coarse aggregate (lbs) per section of the column according 
to Equation 5.2. 
                                     [ ]
MMBM
CACACA ??= 0052.0007.0                              Eq. 5.2 
Where: 
 CA
M
 is the mass of coarse aggregate (lbs) in 1 yd
3 
of concrete.   
 
 140
5.3.6 Bleeding Test 
Bleeding tests were performed on all SCDOT concrete mixtures via the procedure 
in ASTM C 232 (1998), Standard Test Method for Bleeding of Concrete using Method A.  
The purpose of this test was to determine the relative quantity of mixing water that will 
bleed from a freshly mixed concrete sample.  All equipment used met the requirements of 
this specification.  The ? cubic foot container, scale, pipet, mallet, and glass graduate can 
be seen in Figure 5.10.  After placement of the concrete mixture into the ? cubic foot 
container, the accumulated bleed water was drawn off the surface until cessation of 
bleeding.  The accumulated bleed water was placed into a 100-mL graduate and recorded 
after each transfer.  The total amount of bleed water was recorded and expressed as a 
percentage of the net mixing water contained in the test specimen.  This procedure was 
followed as closely as possible for all SCC mixtures with the following modifications.  
These modifications were necessary to account for SCC characteristics. 
1. The SCC mixtures were placed in the container in one continuous lift 
without any rodding.  
2. The tapping of the sides 10 to15 times with the approximate mallet was 
not conducted for the SCC mixtures.  
 
 141
Figure 5.10 ? Testing Equipment for Bleeding Test 
5.3.7 Unit Weight and Air Content 
The unit weight and air content was determined for all concrete mixtures via the 
procedure in ASTM C 138 (1998), Standard Test Method for Unit Weight, Yield, and Air 
Content.  The purpose of this test was to determine the weight per cubic foot and air 
content of freshly mixed concrete.  All equipment used met the requirements of this 
specification.  The balance, 5/8 inch tamping rod, measure, strike off plate, and mallet 
can be seen in Figure 5.11.  This procedure was followed as closely as possible for all 
SCC mixtures with the following modifications.  These modifications were necessary to 
account for SCC characteristics. 
1. The SCC mixtures were placed in the measure in one continuous lift 
without any rodding.  
2. The tapping of the sides 10 to15 times with the approximate mallet was 
reduced to no more than 5 soft taps by hand or mallet for all SCC 
mixtures.  The purpose of this exercise was to help alleviate any large 
 142
entrapped air pockets that remained along the cylinder walls while 
providing little or no consolidation effort. 
 
         
 
 
 
 
 
 
 
Figure 5.11 ? Testing Equipment for Unit Weight and Air Content 
 
5.3.8 Making and Curing Specimens 
The making and curing of concrete specimens were performed according to 
ASTM C 192 (1998), Standard Practice for Making and Curing Concrete Test 
Specimens in the Laboratory.  After strike off, all specimens were capped with a tightly 
sealed lid.  The cylinders remained in the mixing room for a period of 24 hours or until 2 
times the initial set was achieved due to extended setting times of the drilled shaft 
concrete mixture.  Cylinders were then relocated from the mixing room, stripped of their 
molds, and placed in a moist curing room.  The conditions of the moist cure room were 
held constant at a temperature of 73
o
 F and relative humidity of 100%.  The cylinders 
remained in the curing room until testing.  This procedure was followed as closely as 
 143
possible for all SCC mixtures with the following modifications.  These modifications 
were necessary to account for SCC characteristics. 
1. The SCC mixtures were placed into the cylinder molds in one continuous 
lift without any rodding.  
2. The tapping of the sides 10 to 15 times with the approximate mallet was 
reduced to no more than 5 soft taps by hand or mallet for all SCC 
mixtures.  The purpose of this exercise was to help alleviate any large 
entrapped air pockets that remained along the cylinder walls while 
providing little or no consolidation effort. 
 
5.3.9 Time of Set  
Setting tests were performed on all SCDOT concrete mixtures via the procedure 
in ASTM C 403 (1998), Standard Test Method for Time of Setting of Concrete Mixtures 
by Penetration Resistance.  The purpose of this test was to determine the time of setting 
for freshly mixed concrete mixture by means of penetration resistance.  All equipment 
used met the requirements of this specification.  The mortar container, penetration 
needles, pipet, and loading apparatus can be seen in Figure 5.12.  Each mortar sample 
was obtained by vibrating a portion of the concrete mixture over a No. 4 sieve, and then 
placing the mortar into the metal container shown in Figure 5.12.  The specimens were 
kept sealed by a tightly placed lid to prevent the occurrence of evaporation.  Prior to the 
removal of the bleed water, a wedge was inserted under the container to facilitate the 
collection of bleed water.  The lid was then removed for bleed water draw off and testing.  
The testing consisted of making no less than six penetrations until at least one penetration 
 144
resistance reading equaled or exceeded 4,000 psi.  The specimens were maintained at 
mixing room temperature for the entire period until final set was achieved.  There were 
no necessary modifications to this test to account for SCC characteristics.  
 
 
 
 
 
 
 
 
 
 
 
Figure 5.12 - Testing Equipment for Time of Setting 
 
5.4 HARDENED CONCRETE PROPERTIES 
5.4.1 Compressive Strength 
 The compressive strength of the 6 x 12 inch cylindrical concrete specimens was 
tested in accordance with ASTM C 39 (1998), Standard Test Method for Compressive 
Strength of Cylindrical Concrete Specimens.  The equipment used in the laboratory to 
determine the compressive strength of the specimens met all requirements set forth by 
this standard.  The specimens were tested using unbonded caps that consisted of a steel 
 145
retaining ring and neoprene pads.  The unbonded caps meet all requirements described by 
ASTM C 1231 (1998), Standard Practice for use of Unbonded Caps in Determination of 
Compressive Strength of Hardened Concrete Specimens.  The load rate utilized for the 6 
x 12 inch specimens was 35 psi/sec., which corresponds to a value of 60,000 lbs/min.  
Each specimen was loaded in a 600 kip Forney compression machine as shown in Figure 
5.13 until failure occurred. 
 
Figure 5.13 ? 600 Kip Forney Compression Machine 
 
5.4.2 Modulus of Elasticity  
The modulus of elasticity of the 6 x 12 inch cylindrical concrete specimens was 
tested in accordance with ASTM C 469 (1998), Standard Test Method for Static Modulus 
of Elasticity and Poisson?s Ratio Strength of Concrete in Compression.  The purpose of 
this test was to determine the chord modulus of 6 x 12 inch specimens.  The equipment 
used in the laboratory to determine the elastic modulus of the concrete specimens met all 
 146
requirements set forth by this standard.  The specimens were tested using unbonded caps 
that consisted of a steel retaining ring and neoprene pads.  The unbonded caps meet all 
requirements described by ASTM C 1231 (1998), Standard Practice for use of Unbonded 
Caps in Determination of Compressive Strength of Hardened Concrete Specimens.  A 
Humboldt compressometer equipped with a digital dial gauge was used to determine the 
elastic modulus of the concrete specimen.  The researcher ensured that the 
compressometer was positioned evenly from the top, bottom, and sides.  The concrete 
specimen was subsequently placed in the 600 kip Forney compression machine and tested 
as shown in Figure 5.14.  The load rate utilized for the 6 x 12 inch concrete specimens 
was 35 psi/sec., which corresponds to a value of 60,000 lbs/min.  Each specimen was first 
loaded to 40% of the ultimate strength without recording any data.  The purpose of this 
exercise was to ensure that all equipment was properly seated and working correctly.   
The load was re-applied while recording the appropriate data.  After the data was 
recorded, the modulus of elasticity was determined according to Equation 5.3. 
 
                                        
( )
00005.0
2
12
?
?
=
?
SS
E                                     Eq. 5.3 
 
Where, 
E = Chord modulus of elasticity, psi, 
S
2
 = Stress corresponding to 40% of the ultimate load, psi, 
S
1 
= Stress corresponding to a longitudinal strain of 50 millionths, psi,  
?
2
 = longitudinal strain produce by S
2
  
 
 147
 
Figure 5.14 ? Concrete Specimen with Compressometer Attached 
5.4.3 Drying Shrinkage  
The length change of 3 x 3 x 12 inch concrete specimens was tested in accordance 
with ASTM C 157 (1998), Standard Test Method for Length Change of Hardened 
Hydraulic-Cement Mortar and Concrete.  The purpose of this test was to determine the 
length change of the concrete specimens due to drying shrinkage.  The equipment used in 
the laboratory to determine the length change of the concrete specimens met all 
requirements of this specification.  The concrete specimens were allowed to cure for 28 
days in a lime saturated bath.  Afterwards, the concrete specimens were removed and 
placed into air storage.  The air storage room met all requirements stated in this 
specification.  A Humboldt length comparator equipped with a digital dial gauge was 
used to determine the length change of the concrete specimens.  The use of a digital 
 148
gauge helped reduce operator error and allowed more accurate measurements to be taken.  
The length comparator can be seen by looking at Figure 5.15.   
 
Figure 5.15 ? Humboldt Length Comparator, Mold, and Concrete Specimen 
5.4.4 Permeability  
The permeability of 4 x 8 inch concrete specimens was tested in accordance with 
ASTM C 1202 (1998), Standard Test Method for Electrical Indication of Concrete?s 
Ability to Resist Chloride Ion Penetration.  The purpose of this test was to give an 
indication of the concrete?s permeability by determining the resistance to chloride ion 
penetration by electrical conductance.  The equipment used in the laboratory to determine 
the permeability of the concrete specimens met all requirements set forth by this standard.  
Proove? It cells and a Model 164 Test Set with LED read outs, automatic shut off, and 
automatic processing equipment was used to determine the resistance of ion penetration 
 149
by electrical conductance.  The Model 164 Test Set and Proove? It cells can be seen by 
looking at Figure 5.16.   
The concrete specimens were allowed to cure in moist curing room until time of 
testing.  Afterwards, the concrete specimens were removed from the moist cure room and 
a 2 +/- 1/8 inch slice was cut from the 4 x 8 inch specimen using a water-cooled diamond 
saw.  The cut specimens were subsequently conditioned for testing according to 
requirements set forth by this standard.  After conditioning was completed, the specimens 
were removed from the vacuum desiccator and placed into the Proove? It cells.  The use 
of Proove? It cells allowed the rapid preparation of the concrete specimens after the 
removal from the desiccator.  Furthermore, the Proove? It cells did not require the use of 
cell sealant, which further decreased the preparation time after removal from the 
desiccator.  Each specimen was tested for a period of 6 hours as required by this standard.   
 
Figure 5.16 ? Model 164 Test Set and Proove? It Cells 
 150
 
 
 
 
CHAPTER 6 
 
PRESENTATION AND ANALYSIS OF RESULTS 
 
6.1 INTRODUCTION  
The presentation and analysis of results is presented in this chapter in the following order: 
? Phase I ? Selection of Type and Dosage of HRWRA 
? Phase II ? Effect of Retarder Dosage 
? Phase III ? Appropriate SCC Mixing Procedure 
? Phase IV ? Selection of SCC Properties  
? Phase V ? Methods to Modify the Viscosity of SCC Mixtures 
 
6.2 PHASE I ? SELECTION OF TYPE AND DOSAGE OF HRWRA  
 The appropriate type and dosage of HRWRA was selected to provide a concrete 
mixture that was within the proposed quality control limits and that showed adequate 
fresh concrete properties after 30 minutes of continuous mixing.  Table 6.1 and Figure 
6.1 presents the results obtained from Phase I.  Figure 6.1 shows that the slump flow 
increased as the dosage of Glenium 3030 NS increases; this is expected since the fluidity 
of a concrete mixture will increase as the HRWRA dosage increases.  It can also be 
concluded from this figure that the Glenium 3000 NS appeared to be more effective at the 
same dosage amount of Glenium 3030 NS.  Although the Glenium 3000 NS was more 
effective than the Glenium 3030 NS at the same dosage amount, it produced an 
undesirable thick-flakey film on top of cured specimens.   
Table 6.1 and Figure 6.1 demonstrate that the slump flow decreased with 
continuous mixing.  Thus, transportation time must be taken into consideration when 
 151
determining the appropriate HRWRA dosage.  The results further indicate that dosages of 
8 oz/cwt of Glenium 3000 NS and 10 oz/cwt Glenium 3030 NS were within the specified 
range of slump flow values of 21 ? 3 inches upon completion of mixing.  The dosage of 8 
oz/cwt of Glenium 3000 NS produced a concrete mixture with a VSI rating of 1.5 at a 
slump flow value of 23 ? inches, a VSI rating that is not acceptable for this research 
project.  On the other hand, a dosage amount of 10 oz/cwt of Glenium 3030 NS produced 
a concrete mixture that had appropriate fresh concrete properties after 30 minutes of 
continuous mixing.  Based upon these results, it was determined that the appropriate type 
of HRWRA to be used throughout this research project should be Glenium 3030 NS, with 
a dosage amount of 10 oz/cwt to produce desirable fresh concrete properties after 30 
minutes of continuous mixing under controlled laboratory conditions. 
  Table 6.1 ? Fresh Concrete Properties for Phase I 
8 oz/cwt Glenium 
3030 NS
8 oz/cwt Glenium 
3000 NS
10 oz/cwt Glenium 
3030 NS
12 oz/cwt Glenium 
3030 NS
Slump Flow 
(inches)
21 31.5 27 30.5
VSI 031.52.
T50 (sec.) 2.65 0.68 1.1 0.91
Slump Flow 
(inches)
14 23.75 21 25
VSI 0 1.5 1 1.5
T50 (sec.) >30 1.09 1.31 1.22
Air Content (%) 33 * *
Temp. (
o
F) 77 77 75 81
Unit Weight (lb/ft
3
) 144.9 145.6 144 146.9
Pl
a
n
t
J
ob S
i
t
e
Batch ID
Item
 
   *The air content meter was not available for use. 
 
 
 152
0
6
12
18
24
30
36
10 15 20 25 30 35 40
Concrete Age (minutes)
S
l
um
p
 Fl
ow
 
(
i
n
c
h
es)
8 oz/cwt Glenium 3030 NS
8 oz/cwt Glenium 3000 NS
10 oz/cwt Glenium 3030 NS
12 oz/cwt Glenium 3030 NS
Proposed Quality 
Control Limits 
Figure 6.1 ? Slump Flow vs. Concrete Age for Phase I 
 
 
6.3 PHASE II ? EFFECT OF RETARDER DOSAGE  
 In this phase, the effect of the retarding admixture on the retained workability was 
examined by varying the Delvo dosage from 0 oz/cwt to 8 oz/cwt in increments of 4 
oz/cwt.  Table 6.2 presents the fresh concrete properties obtained for Phase II.  Figure 6.2 
demonstrates how the slump flow varied with concrete age for each concrete batch, while 
Figure 6.3 shows the results obtained from the setting test.   
From Figure 6.2, it is clear that retarding admixtures have an effect on the 
retained workability on the concrete mixtures.  It can be seen that the concrete mixture 
that contained no retarding admixtures lost its workability at an incredibly rapid rate from 
a slump flow of 16 inches to a slump flow of 8 inches, which corresponds to a slump of 0 
 153
inches, within 3 hours after the first batch would have been placed.  This rapid loss is 
undesirable for a drilled shaft concrete mixture in applications where retained workability 
is required.  Figure 6.2 further reveals that the addition of 4 oz/cwt of Delvo was quite 
effective in increasing the time in which the concrete mixture remained workable.  Figure 
6.3 shows that 4 oz/cwt of Delvo extended the initial set of the concrete mixture from 364 
minutes to 552 minutes (~ 3 hours).  This corresponded to a slump increase from 0 inches 
after 3 hours to 5 inches (slump flow ? 9.5 in.) after 4 ? hours.   
By looking at Figure 6.3, the increase of Delvo dosage from 4 oz/cwt to 8 oz/cwt 
extended the initial set time from 552 minutes to 783 minutes (3 hours and 50 minutes).  
This increase in initial set corresponded to an increase of slump from 5 inches (slump 
flow ? 9.5 in.) to 7 inches (slump flow ? 11 in.) at approximately the same concrete age.  
Although the retained workability was increased, the change was less compared to the 
change from 0 oz/cwt to 4 oz/cwt or from 0 oz/cwt to 8 oz/cwt of Delvo.  
It must be emphasized that the retained workability of concrete is not only a 
function of the extended initial set, but it is also a function of other factors such as 
temperature effects, long-term effectiveness of the HRWRA, and the effect of different 
supplementary cementitious materials on the hydration rate.  Therefore, the dosage of 
retarding admixture should be sufficient to compensate for these effects and provide the 
extended initial necessary for the duration of the pour so that retained workability and 
shaft completion can be achieved.  This phase has shown that the use of retarding 
admixtures can be very effective in extending the time in which the concrete mixture will 
remain workable.   
 
 154
                               Table 6.2 ? Fresh Concrete Properties for Phase II 
0 oz/cwt Delvo 4 oz/cwt Delvo 8 oz/cwt Delvo 
Slump Flow 
(inches)
25 28 29
VSI 122
T50 (sec.) 1.59 0.53 0.68
Slump Flow 
(inches)
16 17.5 19
VSI 011
T50 (sec.) >30 >30 >30
Air Content 
(%)
2.7 2.8 2.8
Temp. (
o
F) 71 72 71
Unit Weight 
(lb/ft
3
)
144 144.6 144
Batch ID
Pl
a
n
t
Jo
b
 S
i
t
e
Item
 
0
6
12
18
24
30
0 60 120 180 240 300 360
Concrete Age (minutes)
S
l
um
p F
l
ow
 (
i
nc
h
e
s
)
 
0 oz/cw t Delvo
4 oz/cw t Delvo 
8 oz/cw t Delvo 
Proposed Quality 
Control Limits
 
 
Figure 6.2 ? Slump Flow vs. Concrete Age for Phase II 
 155
 
0
1,000
2,000
3,000
4,000
5,000
6,000
200 300 400 500 600 700 800 900 1000
Concrete Age (minutes)
P
e
n
e
t
r
at
i
o
n
 R
e
si
st
an
ce 
(
p
si
)
0 oz/cw t Delvo 4 oz/cw t Delvo 8 oz/cw t Delvo
INITIA L SET
FINAL SET
                 
Figure 6.3 ? Penetration Resistance vs. Concrete Age for Phase II 
 
6.4 PHASE III - APPROPRIATE SCC MIXING PROCEDURE 
 In order to determine an appropriate SCC mixing procedure to be used throughout 
this research project, two different mixing procedures were compared in this phase.  
Table 6.3 presents the fresh concrete properties, while Figure 6.4 illustrates how the 
slump flow varied with concrete age for Phase III.  It can be seen from these results that 
addition of the HRWRA before (mixing process 1) or after (mixing process 2) the 
addition of cementitious materials had no significant affect on the short or long term 
concrete workability.  Based on these results, it was determined that mixing procedure 2 
was the appropriate mixing procedure to be used throughout the laboratory portion of this 
research project.  This decision was based on several factors that included the following:  
 156
? The determination of the water slump was relatively easy and quick to perform 
under laboratory conditions.   
?  By obtaining a water slump any excess free water due to inaccurate moisture 
corrections could be avoided.   
? The water slump was an indicator of the concrete mixture?s consistency due to the 
mixing water alone.  Later observations found that the stability of the SCC 
mixtures were sensitive to free water.  Due to this fact, the water slump assisted in 
determining the appropriate mixture proportions to be used for several SCC 
mixtures.   
 
 
                    Table 6.3 ? Fresh Concrete Properties for Phase III 
 
 
Mixing Process 1 Mixing Process 2
Wet Slump 
(inches)
NA 4 3/4
Slump Flow 
(inches)
27 26
VSI 1.5 1.5
T50 (sec.) 1.23 1.44
Slump Flow 
(inches)
16 16.5
VSI 00.5
T50 (sec.) >30 >30
Air Content (%) 3.3 3.4
Temp. (
o
F) 73 79
Unit Weight 
(lb/ft
3
)
145.2 144.5
Item
Pl
a
n
t
J
ob S
i
te
Batch ID 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 157
0
6
12
18
24
30
0 60 120 180 240 300 360
Concrete Age (minutes)
S
l
um
p Fl
ow
 (
i
nc
he
s
)
Mixing Process 1
Mixing Process 2 
Proposed Quality 
Control Limits
 
Figure 6.4 ? Slump Flow vs. Concrete Age for Phase III 
 
6.5 PHASE IV - SELECTION OF SCC PROPERTIES 
6.5.1 Fresh Concrete Properties and Workability 
The fresh concrete properties for both the ordinary drilled shaft concrete (ODSC) 
and SCC mixtures are presented in Tables 6.4 and 6.5.  The data in Table 6.4 indicates 
that the ODSC mixtures were found to be within the specified range of slump values at 
placement in addition to demonstrating typical workability characteristics for wet-hole 
construction.  As seen in Tables 6.4 and 6.5 the SCC mixtures typically contained more 
entrapped air than the ODSC mixtures.  It is hypothesized that the HRWR admixture 
Glenium 3030 NS increased the entrapped air compared to the MRWR admixture 
PolyHeed N.  Table 6.5 shows that no SCC mixtures possessed appropriate workability 
characteristics at the batch plant location.  The SCC mixtures exhibited signs of 
 158
segregation by evidence of the VSI rating at higher slump flow values.  However, after 
50 minutes of continuous mixing the SCC mixtures were found to be within the specified 
quality control limits set forth in this research. The results further indicate that the 
stability of the SCC mixtures tends to increase as the water slump was reduced, as 
indicated by the differences among the VSI ratings for the SCC mixture, and especially 
for the silica fume and GGBFS mixtures at higher slump flow values. 
Tables 6.4 and 6.5 reveal that the ODSC mixtures did not show an excessive loss 
of workability due to continuous mixing compared to the SCC mixtures.  For instance, 
after 50 minutes of continuous mixing, the highest slump loss experienced by the ODSC 
mixtures was ? inch compared to the least amount of slump flow loss by any SCC 
mixture of 6.5 inches.  Thus, it is obvious that the SCC mixtures were more sensitive and 
experienced more workability loss when subjected to the same mixing conditions.  
Despite this issue, the SCC mixtures were capable of providing an increase in workability 
at placement compared to the ODSC mixtures.  This enhanced workability is apparent in 
Figures 6.5 and 6.6.   
Table 6.4 ? Fresh Concrete Properties for ODSC Mixtures 
 
159
 
 
 
 
 
 
 
 
 
 
 
 
 
1:ODSC 2:ODSC
Slump  
(inches)
8.5 8.75
Air Content 
(%)
2.4 2
Temp. (
o
F) 73 73
Unit 
Weight 
(lb/ft
3
)
146.7 146.5
Item
Pl
a
n
t
Jo
b
 S
i
t
e
ODSC Mixtures
Slump 
(inches)
99
Table 6.5 ? Fresh Concrete Properties for SCC Mixtures 
3:41-48-FA 4:41-44-FA 5:41-40-FA 6:36-40-FA 7:36-40-SG 8:36-40-SF 9:36-44-FA
Slump 
Flow 
(inches)
29 30 30 30 27.5 26 28
VSI 2.533221.52
T50 
(sec.)
0.97 1.41 1.13 1.31 1.59 1.25 1.60
Wet 
Slump 
(inches)
4 5 6 1.5 3/4 3/4 1.0
Slump 
Flow 
(inches)
16.5 19.0 18.0 20.5 19.0 19.5 20.0
VSI 1.0 1.0 1.0 0.5 0.5 0.5 0.5
T50 
(sec.)
>30 >30 >30 2.31 >30 >30 2.47
Air 
Content 
(%)
3.8 3.5 4.2 3.5 4.5 5.1 3.8
Temp. 
(
o
F)
73 71 74 77 77 79 76
Unit 
Weight 
(lb/ft
3
)
143.6 144.4 144.6 146.8 146 143.7 145.3
Pl
ant
Jo
b Si
t
e
Item
Self-Consolidating Concrete Mixtures
 
 160
160 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6.5 ? Workability of ODSC Mixture (approximately 8.25 inches) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6.6 ? Workability of SCC Mixture (approximately 20 inch slump flow) 
 
 161
Figures 6.7 and 6.8 present the slump or slump flow loss versus concrete age for 
the ODSC and SCC mixtures.  Figure 6.7 shows that the ODSC mixtures displayed 
desirable slump retention characteristics in which the slump slowly diminished and 
exceeded 5.5 inches after 6 hours.  This corresponded to a slump loss of 3 inches for 
1:ODSC and 2:ODSC after placement.  On the other hand, the slump flow loss for the 
SCC mixtures ranged from 6.5 to 10 inches after placement, which corresponds to a 
slump loss of more than 5 inches.  Therefore, the SCC mixtures were more inclined to 
have a larger change in workability for the same amount of time compared to the ODSC 
mixtures.  Although the SCC mixtures experienced larger changes in workability, the 
workability of the SCC mixtures was generally similar or higher than those of the ODSC 
mixtures after 5.5 to 6.5 hours as shown in Figure 6.9.  It can be concluded from Figures 
6.7 through 6.9 that at a concrete age of 5.5 to 6.5 hours both the ODSC and SCC 
mixtures would have complied with the recommendation provided by O?Neill and Reese 
(1999) that states that the drilled shaft concrete should have at least 4 inches of slump 
after 4 hours, but neither mixture would have met the recommendation provided by 
Brown (2004) that suggests that the drilled shaft concrete mixture should not experience 
a slump loss of no more than 2 inches for the duration of the pour.  This is considering 
the fact that the duration of the pour was over 6 hours.  
The data on Figure 6.8 indicate that the SCC mixtures that incorporated 4 oz/cwt 
of the mid-range water reducing admixture PolyHeed 1025 seem to maintain their 
workability better than those that contained only the Glenium 3030 NS.  The SCC 
mixture 6:36-40-FA seems to be an outlier among this trend.  Two primary factors are 
thought to have contributed to this outcome.  Firstly, it is believed that the decrease in set 
 162
time for 6:36-40-FA mixture seen in Figure 6.10 may have increased the rate of slump 
flow loss.  Moreover, after the mixing for the 6:36-40-FA mixture was complete, it was 
found that slump flow of the 6:36-40-FA mixture was very low.  The mixture was re-
dosed with 3 oz/cwt of Glenium 3030 NS to achieve a slump flow 20.5 inches, and as 
reported in Section 2.3.2 the workability regained from the re-dosage by HRWRA may 
decrease at a faster rate.   
 
1
3
5
7
9
11
0 60 120 180 240 300 360
Concrete Age (minutes)
S
l
um
p (
i
nc
he
s
)
 
1:ODSC
2:ODSC
SCDOT  Quality 
Control Limits
                            Figure 6.7 ? Slump vs. Concrete Age 
 
 
 
 
 
 
 
 163
0
6
12
18
24
30
0 60 120 180 240 300 360 420
Concrete Age (minutes)
S
l
u
m
p F
l
ow
 (
i
nc
he
s
)
3:41-48-FA 4:41-44-FA 5:41-40-FA 6:36-40-FA
7:36-40-SG 8:36-40-SF 9:36-44-FA
Proposed Quality 
Control Limits
 
Figure 6.8 ? Slump Flow vs. Concrete Age 
 
 
 
0
1
2
3
4
5
6
7
8
9
300 310 320 330 340 350 360 370 380
Concrete Age (minutes)
S
l
um
p (
i
nc
he
s
)
1:ODSC
2:ODSC
3:41-48-FA
4:41-44-FA
5:41-40-FA
6:36-40-FA
7:36-40-SG
8:36-40-FA
9:36-44-FA
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6.9 ? Slump vs. Concrete Age for all Concrete Mixtures 
 164
0
500
1000
1500
2000
2500
3000
3500
4000
4500
600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100
Concrete Age (minutes)
P
e
n
e
t
r
at
i
o
n
 R
e
sist
an
ce
 
(
p
s
i
)
1:ODSC 2:ODSC 3:41-48-FA 4:41-44-FA 5:41-40-FA 6:36-40-FA
7:36-40-SG 8:36-40-SF 9:36-44-FA
Initial Set
Final Set
Figure 6.10 ? Penetration Resistance vs. Concrete Age  
 
6.5.2 Segregation and Bleeding Results   
The results from the segregation column and bleeding tests are summarized in 
Table 6.6.  The data on Tables 6.5 and 6.6 indicate that the SCC mixtures were placed 
into the column mold at the lower end of the proposed quality control limits and at a VSI 
rating of 1 or less.  Under such conditions the SCC mixtures were stable and exhibited 
minimal segregation.  However, the observed behavior of the SCC mixtures suggests that 
at higher values of slump flows and VSI ratings above 1 that the SCC mixtures would 
demonstrate a higher degree of segregation.  For example, Table 6.5 shows that the fly 
ash (FA) SCC mixtures tested at the batch plant showed signs of segregation at higher 
 165
slump flow values.  This segregation was evident by a thick mortar layer on the surface 
of the tested concrete in the mixing drum as well as clear evidence of segregation in the 
flow patty.  Thus, it is reasonable to believe that if segregation column tests were 
performed under these conditions, the coarse aggregate concentration in the bottom 
sections would be higher, and the values of the segregation index would be increased.  
 Regarding the bleeding test, the ODSC mixtures demonstrated a higher degree of 
bleeding compared to the SCC mixtures prepared at the same water-to-cementitious 
materials ratio.  It is thought that this higher degree of bleeding could possibly be due to 
the fact that the initial set for the ODSC mixtures was extended at least 9 hours compared 
to the SCC mixtures as shown in Figure 6.10.  This allowed a much longer time frame in 
which the ODSC mixtures could bleed.  Furthermore, the SCC mixtures typically 
contained a higher percentage of entrapped air, which is very effective in reducing 
bleeding.  Lastly, the incorporation of the VMA for the SCC mixtures may have assisted 
in the reduction of bleed water.  However, it should be noted that the influence of the new 
polyethylene glycol based VMAs on bleeding is not well known.  Further evaluation of 
Table 6.6 reveals that the SCC mixtures prepared at a water-to-cementitious materials 
ratio of 0.36 limited the amount of bleeding.   
 
 
 
 
 
 
 166
Table 6.6 ? Segregation and Bleeding Results 
Mixture
Slump or 
Slump Flow 
(inches)
Segregation Index (%) Bleeding (%)
1:ODSC
8.50 * 2.05
2:ODSC 8.75 * 2.34
3:41-48-FA 16.5 0.0379 0.33
4:41-44-FA 19 0.51 0.54
5:41-40-FA 18 0.41 0.77
6:36-40-FA 20.5 0.53
0
**
7:36-40-SG 19 0.15
0
**
8:36-40-SF 19.5 0.56
0
**
9:36-44-FA 20 0.54
0
**
* Not Conducted for ODSC Mixtures                                   
**Bleeding was difficult to measure. Any water present at the 
surface was not clear and consisted primarily of cementitious 
materials.
 
6.5.3 Passing Ability: J-Ring and L-Box 
 The test results of the J-Ring and those of the L-Box are summarized in Table 
6.7.  Regarding the (FA) SCC mixtures, those prepared with sand-to-aggregate ratios of 
0.44 and 0.48 exhibited greater passing ability among closely spaced reinforcement using 
the J-Ring than those prepared with a sand-to-aggregate ratio of 0.40.  This could be due 
to the fact that the (FA) mixtures prepared at a sand-to-aggregate ratio of 0.40 contained a 
higher amount of coarse aggregate that increased the collision and interaction among the 
solid particles at the vicinity of the reinforcement that resulted in a greater tendency of 
blockage.  The (SF) and (SG) mixtures prepared with a sand-to-aggregate ratio of 0.40 
demonstrated a passing ability similar to the fly ash (FA) mixtures prepared with sand-to-
aggregate ratios of 0.44 and 0.48.  However, no other (SF) and (SG) mixtures were 
prepared at varying sand-to-aggregate ratio.  Therefore, no conclusion can be drawn in 
 167
regards to if (SF) and (SG) mixtures prepared at higher sand-to-aggregate ratios would 
show greater passing ability at similar slump flows.  It can be seen from Table 6.7 that all 
SCC mixtures demonstrated very low passing ability using the L-Box apparatus.  This is 
due to the fact that the maximum size aggregate size of ? inch used for this research 
project was simply too large for the clear spacing between the reinforcement in the L-Box 
apparatus.  For example, the clear spacing between the reinforcement for the L-Box as 
recommended by the PCI (2003) was 1.375 inches, which corresponds to less than 2 
times the maximum aggregate size.  This spacing is unrealistic for most drilled shaft 
applications, but if very congested reinforcement cages exist the L-Box could be used to 
ensure high passing ability of the SCC mixture.  In case of this research, the L-Box 
apparatus was found to be ineffective in determining the passing ability of SCC mixtures 
designed for drilled shaft applications.  As a result, the blocking ratios determined from 
the L-Box should be disregarded for this research.   
 
Table 6.7 ? Passing Ability Results for SCC Mixtures 
 
L-Box
Diameter 
(inches) 
Inverted
T
50
(sec) 
Inverted
VSI
J-Ring 
Flow 
(inches) 
Inverted
Ratio of 
J-Ring 
Flow to 
Slump 
Flow
Passing 
Ability 
Rating
h
2
/h
1
3:41-48-FA 20 1.28 1 17.5 0.88 2 0.27
4:41-44-FA 20.5 2.13 1 18 0.88 2 0.3
5:41-40-FA 20 1.91 1 16 0.8 2 0.078
6:36-40-FA 20 3.9 0.5 16 0.8 2 0.059
7:36-40-SG 20.5 5.03 1 18 0.88 2 0
8:36-40-SF 22 1.69 0.5 20.5 0.93 1 0.087
9:36-44-FA 20.5 2.25 0.5 18 0.88 2 0.036
Slump Flow J-Ring 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 168
6.5.4 Compressive Strength  
The results for the compressive strength testing for the ordinary drilled shaft 
concrete (ODSC) and SCC mixtures are given in Figure 6.11.   Regarding the (FA) SCC 
mixtures, Figure 6.11 indicates that regardless of the water-to-cementitious materials 
ratio, it appears that the sand-to-aggregate ratio did not influence the strength 
development.  Figure 6.11 further reveals that the SCC mixtures prepared at a water-to-
cementitious materials ratio of 0.41 demonstrated slightly lower compressive strengths 
compared to those of the ODSC mixtures.  However, the average difference among the 
compressive strengths is reduced as the SCC mixtures continue to hydrate.  The average 
difference between the compressive strengths are 15.5%, 12%, 10.5%, 9%, and 6.5% at 
ages of 3, 7, 14, 28, and 56-day, respectively.  It is thought that the slightly lower 
compressive strengths can be attributed to the following:  
? The SCC mixtures contained 8% higher replacement percentage of cement by fly 
ash compared to the ODSC mixtures. Therefore, the amount of early heat 
evolution is decreased and in turn reduces the early age strength, but not the long 
term strength.   
? Secondly, Mindess et al. (2003) reports that there is only enough calcium 
hydroxide in the paste in which the Class F fly ash can react to form calcium 
silicates.  This would suggest higher replacement percentages of fly ash may 
result in unreacted ash causing a slight reduction in compressive strengths.   
 
Further evaluation of Figure 6.11 shows that the reduction in water-to-
cementitious materials ratio from 0.41 to 0.36 for the (FA) SCC mixtures increased the 
 169
compressive strength, on average, by 1600 psi at 28-days.  This is expected since it is a 
well known fact that the compressive strength is increased as the water-to-cementitious 
materials ratio decreases.  Furthermore, the use of the silica fume or ground granulated 
blast furnace slag (GGBFS) was found to increase the compressive strength compared to 
the (FA) SCC mixtures.   
In addition to the continuing pozzolanic reaction between the amorphous silica in 
the silica fume and the calcium hydroxide, the high fineness of the silica fume allows the 
particles to pack densely between the cement particles and improves the interfacial 
transition zone.  As a result, the silica fume greatly reduces the void spaces within the 
cement paste, and the bond of the cement paste with the aggregate is improved allowing 
the aggregate to better participate in stress transfer (Neville 1996).  These contributions 
provided by the silica fume can be capable of generating higher compressive strength 
compared to the use of fly ash alone as in the case of this research.   
Unlike fly ash, high replacements of GGBFS, with values ranging from 25-65%, 
can be utilized since GGBFS have cementitious properties of their own and only 10-20% 
of cement is needed for activation.  The hydration of GGBFS produces primarily calcium 
silicates and produces less calcium hydroxide than portland cement alone in addition to 
showing some pozzolanic behavior (Neville 1996).  Neville (1996) reports that 
progressive release of alkalis by the GGBFS along the formation calcium hydroxide by 
portland cement results in a continuing reaction of GGBFS over a long period of time.  
Thus, there is a long term strength gain associated with the GGBFS.  For these reasons, 
high compressive strengths at higher replacement values of portland cement by GGBFS 
can be achieved as in the case of this research.  
 170
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
C
o
m
p
re
s
s
i
v
e
 S
t
re
n
g
t
h
 
(
p
s
i
)
1:ODSC 2:ODSC 3:41-48-FA 4:41-44-FA 5:41-40-FA
6:36-40-FA 7:36-40-SG 8:36-40-SF 9:36-44-FA
Figure 6.11 ? Compressive Strength vs. Concrete Age for Phase IV 
 
 
6.5.5 Modulus of Elasticity 
 The modulus of elasticity was determined for all concrete mixtures in 
conjunction with the compressive strength tests.  Figure 6.12 presents the results obtained 
for the ordinary drilled shaft concrete (ODSC) and SCC mixtures.  Generally speaking, 
the development for the modulus of elasticity is similar to the strength development 
provided in Figure 6.11.  For example, the SCC mixtures prepared at a water-to-
cementitious materials ratio of 0.41 demonstrated slightly lower elastic modulus values at 
early ages compared to those for the ODSC mixtures, and as the SCC mixtures continue 
to hydrate the difference among these mixtures are decreased.  This should be expected 
 171
since the modulus of elasticity is a function of the compressive strength.  This 
relationship between compressive strength and modulus of elasticity can further be seen 
by examining the silica fume and GGBFS mixtures.  Figure 6.12 shows that the silica 
fume and GGBFS mixtures that exhibited higher compressive strengths also show higher 
modulus of elasticity values compared to the fly ash (FA) SCC mixtures at the same 
water-to-cementitious materials ratio.  Furthermore, it appears from Figure 6.12 that the 
modulus of elasticity for the fly ash SCC mixtures was not significantly affected by the 
varying sand-to-aggregate ratio.   
  In order to determine if the calculated elastic modulus for the concrete mixtures is 
of typical sound concrete; the calculated modulus of elasticity in this research was 
compared with the ACI 318 (2002) Building Code (
ccc
fWpsiE '33)(
5.1
?= ) and the 
ACI Committee 363 (2002) ?State-of the-Art Report on High-Strength Concrete? 
( )000,000,1'000,40)( += cfpsiE
c
models (see Chapter 2).  These results are presented 
in Figures 6.13 and 6.14.  Figure 6.13 reveals that the ACI 318 (2002) overestimated the 
modulus of elasticity for both the ODSC and SCC mixtures.  Furthermore, the ACI 318 
(2002) was found to increasingly overestimate the modulus of elasticity as the 
compressive strength increased.  This finding coincides with ACI Committee 363 (2002) 
that found that the equation used by the ACI 318 (2002) was only valid for compressive 
strengths up to 6,000 psi.  On the other hand, the ACI Committee 363 (2002) equation 
provided an improved and typically a conservative estimate for the modulus of elasticity 
for both the ODSC and SCC mixtures as shown in Figure 6.14.  It is believed that the 
improved and conservative estimation for the modulus of elasticity lies in the fact that the 
 172
equation provided by the ACI Committee 363 (2002) is valid for compressive strengths 
from 3,000 to 12,000 psi.   
2
3
4
5
6
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
M
odul
us
 
o
f
 E
l
a
s
t
i
c
i
t
y
 (
1
.
0
 x
 
1
0
6
 ps
i
)
1:ODSC 2:ODSC 3:41-48-FA 4:41-44-FA 5:41-40-FA
6:36-40-FA 7:36-40-SG 8:36-40-SF 9:36-44-FA
 Figure 6.12 ? Modulus of Elasticity vs. Concrete Age for Phase IV 
 
 
 
 
 173
0
1
2
3
4
5
6
0123456
Measured Elastic Modulus (1.0 X 10
6
 psi)
P
r
e
d
ic
t
e
d 
E
l
a
s
t
ic
 M
odulus
 (
1
.0
 X
 
1
0
6
 p
s
i)
1:ODSC
2:ODSC
3:41-48-FA
4:41-44-FA
5:41-40-FA
6:36-40-FA
7:36-40-SG
8:36-40-SF
9:36-44-FA
Line of Equality
-10%Error
+10% Error
Figure 6.13 ? Predicted vs. Measured Elastic Modulus according to ACI 318 (2002)   
                        Equation for Phase IV 
0
1
2
3
4
5
6
0123456
Measured Elastic Modulus (1.0 X 10
6
 psi)
P
r
e
d
ic
t
e
d E
l
a
s
t
ic
 M
odulus
 (
1
.0
 X
 1
0
6
 p
s
i)
1:ODSC
2:ODSC
3:41-48-FA
4:41-44-FA
5:41-40-FA
6:36-40-FA
7:36-40-SG
8:36-40-SF
9:36-44-FA
Line of Equality
+10% Error
-10%Error
Figure 6.14 ? Predicted vs. Measured Elastic Modulus According to ACI 363(2002)  
                      Equation for Phase IV   
 174
6.5.6 Drying Shrinkage 
 
 The drying shrinkage results for the ordinary drilled shaft concrete (ODSC) and 
SCC mixtures are presented in Figure 6.15.  The data on Figure 6.15 indicate that the 
water-to-cementitious materials ratio appears to be the main factor influencing the 
amount of drying shrinkage.  The results show that the reduction in water-to-cementitious 
materials ratio from 0.41 to 0.36 decreased the specimen?s tendency to shrink.  This trend 
should be expected since the drying shrinkage is known to be reduced as the water-to-
cementitious materials ratio is decreased.  However, it appears that the mixture prepared 
with ground granulated blast furnace slag (SG mixture) produced slightly higher drying 
shrinkage values compared to the other mixtures prepared at a water-to-cementitious 
materials ratio of 0.36.   
Among the SCC mixtures prepared at a water-to-cementitious materials ratio of 
0.41, the results indicate the SCC mixture prepared at sand-to-aggregate ratio of 0.48 
shows evidence of higher drying shrinkage than those prepared at 0.40 and 0.44 as well 
as the highest drying shrinkage overall.  However, the difference in drying shrinkage 
values among these SCC mixtures is actually quite minimal and operator or equipment 
error could very easily alter this outcome.  This data suggest that the SCC mixtures 
prepared at a water-to-cementitious materials ratio of 0.41 exhibited drying shrinkage 
values similar to the ODSC mixtures.  This outcome is reasonable given the fact that the 
paste volume fraction and aggregate volume fraction did not significantly vary compared 
to the SCC mixtures.  Furthermore, Figure 6.15 indicates that the two ODSC mixtures 
showed practically the same drying shrinkage characteristics throughout the test.  This 
 175
indicates that use of the #789 coarse aggregate gradation for 1: ODSC had no significant 
effect on the drying shrinkage values.   
Unfortunately, no absolute conclusion can be made at this time concerning the 
effect of the sand-to-aggregate ratio on the drying shrinkage, due to the lack of drying 
shrinkage data for 9:36:44-FA.  It must be noted that this research will be updated as 
soon as additional test results are available.  
0
100
200
300
400
500
600
0 7 14 21 28 35 42 49 56 63 70 77 84 91
Concrete Age (Days)
D
r
yi
n
g
 S
h
r
i
n
kag
e
 
(
m
i
r
o
s
t
r
ai
n
)
  
1:ODSC 2:ODSC 3:41-48-FA 4:41-44-FA 5:41-40-FA
6:36-40-FA 7:36-40-SG 8:36-40-SF 9:36-44-FA
Figure 6.15 ? Drying Shrinkage vs. Concrete Age 
 
 
 
 
 176
6.5.7 Permeability   
Results of the rapid chloride permeability tests (RCPT) for the ordinary drilled 
shaft concrete (ODSC) and SCC mixtures are given in Figures 6.16 and 6.17.  The RCPT 
values at 91-days for the ordinary drilled shaft concrete mixtures were 4530 and 4562 as 
compared to 2584, 2773, and 3067 for the SCC mixtures at the same water-to-
cementitious materials ratio.  This reduction in RCPT values for the SCC mixtures can be 
attributed to the fact the SCC mixtures contained a higher replacement percentage of fly 
ash (FA).  For example, the SCC mixtures with a water-to-cementitious materials ratio of 
0.41 consisted of 33% replacement of cement by fly ash, where as the ODSC mixtures 
only contained 25% replacement of cement by fly ash.  Since fly ash is notably more 
spherical than cement, the additional replacement of fly ash may have allowed the 
particles to pack more tightly within the pore spaces creating a denser microstructure.   
 Figures 6.16 and 6.17 indicate that the RCPT values were found to decrease from 
91 to 365-days.  As the hydration process proceeds, the interconnected pores that were 
present at 91-days are being filled by the continuous formation of C-S-H and the 
continuous growth of the calcium hydroxide within the capillaries pores.  As a result, the 
porosity of the paste will decrease with time lowering the RCPT values.  It is also 
important to notice that the trends from Figure 6.16 are also present in Figure 6.17.  At 
365-days the ODSC mixtures still exhibited higher RCPT values compared to the SCC 
mixtures at the same water-to-cementitious materials ratio.    
 As discussed in Section 2.4.4, the coefficient of permeability decreases as the 
water-to-cementitious materials ratio is reduced.  The reduction in RCPT values for the 
fly ash (FA) SCC mixtures (particularly 3:41-48-FA, 6:36-40-FA, and 9:36-44-FA) due 
 177
to the decrease in water-to-cementitious materials ratio is evident on Figure 6.16.  The 
reduction in water-to-cementitious materials ratio from 0.41 to 0.36 decreased the RCPT 
values, on average, 1500 coulombs at the same concrete age.  
It is also important to emphasize the effect of the supplementary cementitious 
material on the RCPT values at a water-to-cementitious materials ratio of 0.36.  Figure 
6.16 indicates that the introduction of silica fume considerably reduced the RCPT values 
compared to the (FA) mixtures.  This reduction in RCPT values comes from the ability of 
the silica fume to pack tightly between pore spaces creating a very dense microstructure.  
However, the introduction of ground granulated blast furnace slag (GGBFS) increased 
the RCPT values compared to the fly ash (FA) SCC mixtures.  The increase in RCPT 
values for the (SG) mixture may stem from the angular shape of the GGBFS compared to 
the spherical nature of the fly ash.  Due to this fact, the particles may have not been able 
to pack as closely causing an increase in the interconnected capillary pores. 
 
 
 
 
 
 
 
 
 
 
 178
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
1
:
OD
S
C
2
:O
D
S
C
3
:4
1
-4
8-
FA
4
:4
1
-4
4
-F
A
5
:4
1
-4
0-
FA
6
:3
6
-4
0
-F
A
7
:
36
-
4
0
-S
G
8
:3
6
-4
0
-S
F
9
:
36
-
4
4-
FA
C
oul
om
b
s
 
Figure 6.16 ? 91-Day Permeability Results 
0
200
400
600
800
1000
1200
1400
1:
O
D
S
C
2:
O
D
S
C
3:
41-
48
-
FA
4:
41-
44
-
FA
5:
41-
40
-
F
A
C
o
ul
om
b
s
 
 
Figure 6.17 ? 365-Day Permeability Results 
 179
6.5.8 Comparison between Laboratory and Field Conditions  
 A small scale field study was conducted at APAC Ready Mix Concrete in Marion, 
South Carolina.  The primary objectives of this field study were three fold: 
1. To ensure that the chemical admixture dosages determined for laboratory 
conditions remain sufficient for field conditions. 
2. To evaluate the effect of mixing imposed by a ready mix truck on the slump flow 
after 50 minutes of continuous mixing.  
3. To compare the compressive strength and modulus of elasticity values obtained 
from the field specimens to that of the laboratory specimens. 
The two SCC mixtures selected to be used for this field study were 3:41-48-FA and 6:36-
40-FA.  The SCC mixtures were selected based upon the fact that at the time of this field 
study these mixtures were considered to be the most likely utilized for the full-scale field 
project.  The only modification to these mixtures was that an additional 2 oz/cwt of Delvo 
was added to account for the effect of hot weather conditions on slump retention and time 
of setting.  No ODSC mixtures were selected to be tested for this field study considering 
the fact that the ODSC mixtures used for laboratory purposes have been routinely 
accepted in South Carolina.  The raw materials and chemical admixtures used for this 
small scale field study were provided by the same suppliers as those from the laboratory 
materials.   
Batching and Mixing: Each SCC mixture consisted of two cubic yards of concrete that 
was batched and mixed according to normal operations of the plant with the exception of 
the chemical admixtures.  Figures 6.18 through 6.21 demonstrate how the raw materials 
were obtained and batched at this ready mix concrete plant.  The chemical admixtures 
 180
were added to the SCC mixtures after the ready mix truck exited the material hopper and 
wash down was performed.  This was done for two primary reasons.  Firstly, the 
chemical admixtures needed for the SCC mixtures were not available for automated 
dispensing since they were not used in everyday operation.  Secondly, the chemical 
admixtures were added after the wash down process was performed in order to obtain a 
water slump.  Generally, 3 to 5 gallons of water is typically used for the wash down 
process.  This extra water must be taken into account in the batching process since the 
stability of the SCC mixtures was found to be sensitive to excessive free water.  The 
researcher requested that the plant operator withhold 5 gallons of batching water to 
account for the wash down process.   
A water slump was taken after the batching and wash down process was 
completed.  It was found that obtaining a water slump under field conditions required a 
significant increase in time compared to laboratory conditions.  Under laboratory 
conditions the water slump could be obtained no more than 5 minutes after water-to-
cementitious materials contact; however, under field conditions obtaining the water 
slump required no less than 30 minutes after water-to-cementitious materials contact.  
This was primarily due to the time required to perform the wash down process and 
obtaining a concrete sample for testing.  Unlike laboratory conditions where the concrete 
sample is very accessible and easy to obtain from the mixer, obtaining the concrete 
sample from the ready mix truck required more equipment, people, time, and 
attentiveness to detail due to safety precautions.  Alternatives to this approach could be 
employed in order to reduce the time in which the accuracy of the moisture corrections 
can be determined.  The following procedure could be utilized to accomplish this goal:   
 181
1. The use of wash down water could be prohibited in cases where SCC mixtures are 
used in order to control unwanted water.  By implementing this suggestion no 
water will have to be withheld to account for the wash down process, and the time 
required to check the accuracy of the moisture corrections can be reduced.   
2. It may be possible to check the accuracy of the moisture corrections without 
having to obtain a concrete sample.  This can be accomplished by rotating the 
concrete mixture toward the concrete chute and make a water slump estimate 
based on the observation of the wetness or dryness of the concrete mixture.  Most 
experienced quality control individuals can provide a reasonable estimate of the 
water slump, typically within +/- 1 inch of the actual water slump.   
 
 
 
 
 
 
 
 
 
 
 
Figure 6.18 ? Attaining Raw Materials from Stock Piles 
 182
 
 
 
 
 
 
 
 
 
 
 
Figure 6.19 ? Unloading Raw Materials onto Conveyer Belt 
 
 
 
 
 
 
 
 
 
 
Figure 6.20 - Raw Materials being Delivered to Hopper via Conveyer Belt 
 183
 
 
 
 
 
 
 
 
 
 
 
Figure 6.21 ? Raw Materials being Mixed by Ready Mix Truck  
Fresh Concrete Properties: The fresh concrete properties for the field study are 
presented in Table 6.8 and Figure 6.22.  The fresh concrete properties for the plant 
location were very similar to those of the laboratory, suggesting that the batch sizes 
utilized for laboratory evaluation were sufficient to simulate the performance of the 
chemical admixtures in large batches.  However, the slump flow characteristics for the 
job site location between the laboratory and field conditions produced very different 
results.  It must be noted that in Figure 6.22 the mixing time represents the time of 
mixing after the first slump flow was taken.  This was necessary due to the substantial 
difference in times for obtaining the water slump.  The data in Table 6.8 and Figure 6.22 
indicate that the slump flow loss due to continuous mixing was much less under field 
conditions compared to the laboratory.  The primary reason for this outcome is likely due 
to the rotational speed of the mixing drum for the ready mix truck compared to laboratory 
 184
mixer.  The laboratory mixer was rotated at a higher speed, providing heavy agitation of 
the concrete mixture.  Where as, the mixing drum for the ready mix truck was set to 4-5 
rotations per minute.  The larger batch size used for the field study may have also 
contributed to lower slump loss for the field study.   
After 50 minutes of continuous mixing, the slump flow was found to be outside 
the proposed quality control limits.  The SCC mixtures were allowed to rotate at an 
increased rotational speed for a short duration until the slump flow was found to be 
within the proposed quality control limits.  The slump flow at which cylindrical 
specimens were made for the hardened concrete properties was 20 inches for 3:41-48-FA 
and 21 inches for 6:36-40-FA. 
 
Table 6.8 - Fresh Concrete Properties for both Laboratory and Field Conditions  
 
3:41-48-FA (Lab) 3:41-48-FA (Field) 6:36-40-FA (Lab) 6:36-40-FA (Field)
Slump Flow 
(inches)
29 30 30 28
VSI 2.5 2.5 2 2.5
T50 (sec.) 0.93 1.53 1.31 2.53
Wet Slump 
(inches)
4 ? 3 1.5 ? 1
Slump Flow 
(inches)
16.5 27.5 20.5 26
VSI 1 1.5 0.5 1.5
T50 (sec.) >30 1.62 2.31 3.5
Air Content 
(%)
3.8 3.1 3.46 3.1
Temp. (
o
F) 73 96 75 100
Jo
b
 S
i
t
e
Item
Self-Consolidating Concrete Mixture
Pl
a
n
t
 
 
 185
0
5
10
15
20
25
30
0 5 10 15 20 25 30 35 40 45 50
Mixing Time (minutes)
S
l
u
m
p Flow (
i
nc
h
e
s
)
3:41-48-FA (Lab) 3:41-48-FA (Field) 6:36-40-FA (Lab) 6:36-40-FA (Field)
Figure 6.22 ? Slump Flow vs. Mixing Time under Laboratory and Field Conditions 
 
The concrete temperatures in the field were higher than those for the laboratory as 
indicated in Table 6.8.  Prolonged exposure to high temperatures can be detrimental to 
the slump retention and can significantly decrease setting times.  In order to monitor the 
temperatures for the concrete samples for the slump retention and setting test, an I-Button 
was placed beside the samples until testing was complete.  The temperature profile 
attained from the I-Button is presented in Figure 6.23.  The times specified on Figure 
6.23 are of those in which the first SCC mixture was made until the last setting test was 
complete.  The SCC mixture 3:41-48-FA was batched on 7/27/04 at 10:45 AM and 6:36-
40-FA on 7/27/04 at 2:35 PM.  Figure 6.23 further reveals that the concrete samples were 
exposed to temperatures ranging from 76 to 113 degrees 
o
F.  The corresponding setting 
test results for the field specimens are presented in Figure 6.24.  From this figure it can be 
determined that the SCC mixture 3:41-48-FA under field conditions experienced much 
 186
faster setting times as compared to the laboratory conditions.  The SCC mixture 6:36-40-
FA demonstrated similar set times under field conditions compared to laboratory 
conditions.  The faster set time for 3:41-48-FA may be due to longer exposure to high 
temperatures compared to 6:36-40-FA that experienced high temperatures for a short 
duration followed by a sharp decrease in temperature.      
  The slump retention for 3:41-48-FA was also affected by the high temperatures 
and faster set times.  The slump flow retention for 3:41-48-FA was determined to be 8 
inches after four hours, which corresponded to a slump of approximately 3 ? inches.  
This slump was found to be much less than the laboratory specimen at approximately the 
same concrete age.  On the other hand, the slump flow for 6:36-40-FA was determined to 
be 10 inches after 4 hours, which corresponded to a slump of 6 inches.  This slump flow 
was found to be slightly less than under laboratory conditions even with similar set times.  
These results would suggest that even with similar set times the rate of slump loss is 
increased when exposed to high temperatures.  These results further indicate the need for 
testing to determine the amount of additional retarder needed to account for high 
temperatures to ensure that proper retained workability and set times are achieved.   
 
 
 
 
 
 
 
 187
70
80
90
100
110
120
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Tem
p
er
a
t
ur
e (
o
F)
7/27/04 
10:18AM
7/27/04
12:42 PM
7/27/04
3:06 PM
7/27/04
5:30 PM
7/27/04
7:30 PM
7/27/04
9:54 PM
7/28/04
12:18 AM
7/28/04
2:42 AM
Figure 6.23 ? Temperature Profile Obtained from I-Button 
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 200 400 600 800 1000 1200
Concrete Age (minutes)
P
e
n
e
t
r
a
t
i
o
n
 R
esi
stan
ce
 (
p
si
)
3:41-48-FA Lab 3:41-48-FA Field 6:36-40-FA Lab 6:36-40-FA Field
Initial Set
Final Set
Figure 6.24 ? Penetration Resistance vs. Concrete Age under Laboratory and Field  
                       Conditions 
 188
Hardened Concrete Properties: The results for the compressive strength and modulus 
of elasticity for both SCC mixtures are given in Figures 6.25 and 6.26.  The data 
collected from the compressive strength and modulus of elasticity allowed for a 
comparison between field and laboratory conditions.  It was found that the field 
specimens exhibited slightly higher compressive strengths compared to the laboratory 
specimens.  It is thought that the higher compressive strengths are due to possibly 
withholding extra water for the wash down process, which may have caused a reduction 
in water-to-cementitious materials ratio.  Nevertheless, the compressive strength and 
modulus of elasticity values obtained from the field specimens corresponded well to 
those obtained from the laboratory.  
0
2000
4000
6000
8000
10000
12000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
C
o
m
p
r
e
ssi
v
e
 S
t
r
e
n
g
t
h
 (
p
si
)
3:41-48-FA (Lab) 3:41-48-FA (Field) 6:36-40-FA (Lab) 6:36-40-FA (Field)
Figure 6.25 ? Compressive Strength vs. Concrete Age under Laboratory and Field  
                       Conditions 
 189
0
1
2
3
4
5
6
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
M
odul
us
 
of
 
E
l
a
s
t
i
c
i
t
y
 (
1
.
0
 x
 1
0
 
6
 ps
i
)
3:41-48-FA (Lab) 3:41-48-FA (Field) 6:36-40-FA (Lab) 6:36-40-FA (Field)
 
Figure 6.26 ? Modulus of Elasticity vs. Concrete Age under Laboratory and Field  
                      Conditions 
 
 
6.6 PHASE V - METHODS TO MODIFY THE VISCOSITY OF SCC MIXTURES 
6.6.1 Fresh Concrete Properties 
 Phase V was formulated to clarify the effects of different methods to modify the 
viscosity of SCC mixtures.  Among the SCC mixtures prepared with VMA as the method 
to modify the viscosity, the results indicate at similar slump flow values the viscosity of 
the SCC mixtures was not increased even at high dosage amounts of VMA.  However, to 
some extent the results suggest that the VMA may provide a slight increase in stability at 
higher values of slump flow with increasing VMA dosage.  This is according to the VSI 
ratings provided in Table 6.9 for those mixtures at higher slump flow values.  At lower 
slump flow values the VMA appeared to have no profound effect on the stability of the 
SCC mixtures.   
 190
The results for the SCC mixtures prepared with high dosages of fly ash as the 
method to modify the viscosity reveal that an increase in fly ash percentage did not 
correspond to an increase in viscosity.  In fact, the water slump of the SCC mixtures 
increased as the percentage of fly ash was increased, which resulted in a higher degree of 
segregation at the batch plant locations.  This higher degree of segregation is not evident 
by the VSI ratings provided in Table 6.9 since 3 is the highest VSI rating, but it is an 
observational behavior made by the researcher.  Neither the stability nor the viscosity of 
these SCC mixtures seemed to be significantly affected by the higher percentages of fly 
ash at lower slump values such as those that represent job site testing.   
 The results in Table 6.9 show that the incorporation of the silica fume provided no 
increase in viscosity by evidence of the T
50
 times.  However, the utilization of the silica 
fume was found to improve the stability of the SCC mixtures as can be seen by the 
decreased VSI ratings.  It is believed that this stability can be attributed to the reduction 
of the water slump and absorption of free water due to the high fineness of the silica 
fume.  Replacement percentages of silica fume above 8% were found not to provide a 
considerable increase in stability at similar slump flow values nor a considerable 
reduction in water slump.  Thus, replacement percentages above 8% would not be 
necessary and only result in increased cost.  Furthermore, Table 4.5 indicates that the 
required dosage of HRWRA was increased as the replacement percentage of silica fume 
was increased.   
 The incorporation of GGBFS provided results similar to the silica fume mixtures.  
For example, the GGBFS provided a reduction in the water slump and showed a higher 
degree of stability at the batch plant compared to 6:AL-36-33 FA.  In addition, the 
 191
incorporation of the GGBFS seems to slightly increase the T
50
 times compared to the 
silica fume and fly ash mixtures at similar slump flow values.  As with the silica fume 
mixtures, the required dosage of HRWRA was increased with the incorporation of the 
GGBFS.   
The amount of entrapped air for the GGBFS mixtures was increased with higher 
replacement percentages of GGBFS.  The amount of entrapped air was 4.1% for 13:AL-
36-40 SG, 10.5% for 14:AL-36-50 SG, and 17% for 15:AL-36-60 SG.  These results 
indicate that the amount of entrapped air nearly doubled for every 10% increase in 
GGBFS.  An experiment was conducted to determine if the Glenium 3030 NS was in fact 
the primary cause of this entrapped air.  In this experiment, mixture 14:AL-36-50 SG was 
remade with exactly the same mixture proportions with the Glenium 3030 NS being 
replaced by PolyHeed 1025.  Table 4.5 shows that the required dosage amount of 
PolyHeed 1025 to achieve similar slump flow values at the batch plant was 20 oz/cwt.  
This high dosage amount was necessary due to the fact that the PolyHeed 1025 is a mid-
range water reducing admixture.  The results of this experiment can be seen by 
examining mixture 14:AL-36-50 SG (LA) in Table 6.9, where (LA) stands for low air.  
The results show that when only the PolyHeed 1025 was utilized the amount of entrapped 
air was reduced from 10.5% to 2.6%, respectively.  Based upon these results it was 
determined that the Glenium 3030 NS was the main reason for the increase in entrapped 
air.   
 These results in Table 6.9 show that the Micron 3 did not provide an increase in 
stability or viscosity compared to the fly ash mixtures even at high replacement 
percentages.  This outcome was unexpected since the Micron 3 was considerably finer 
 192
than both the cement and the traditional fly ash.  However, it is believed that this outcome 
is due to the fact that the Micron 3 was in replacement of the cement and not the fly ash. 
Since the Micron 3 is notably more spherical than the cement it provided an increase in 
workability.  This can be seen by observing the increase in water slump for 16:AL-36-8 
M3 compared to 6:AL-36-33 FA.  Earlier results illustrated that as the water slump was 
increased the stability of the mixture was decreased, especially at higher slump flow 
values.  The stability of the Micron 3 mixtures was reduced in spite of the fact that the 
Micron 3 was finer.  Furthermore, the results in Table 6.9 show that the introduction of 
the limestone filler provided no considerable increase in stability, but exhibited a 
reduction in water slump for a constant dosage of HRWRA.  This reduction in water 
slump at the batch plant is most likely due to the reduction of water content from 284 
lb/yd
3
 for the fly ash mixtures to 270 lb/yd
3
 for the limestone filler mixtures as shown in 
Table 4.5.   
 193
Table 6.9 ? Fresh Concrete Properties for Phase V (cont. on next page) 
 
 
 194
1:AL-41-0 VMA 2:AL-41-2 VMA 3:AL-41-10 VMA 4:AL-41-18 VMA 5:AL-36-33 (2) FA 6:AL-36-33 FA 7:AL-36-40 FA 8:AL-36-50 FA
Slump Flow 
(inches)
29 31 29 29 28 32 33 32
VSI 3 3 2.5 2 2 3 3 3
T50 (sec.) 1.1 0.98 0.85 0.9 0.88 0.76 0.62 1.5
Wet Slump 
(inches)
7 6 6 6.5 2.25 3.75 4.00 5
Slump Flow 
(inches)
18.0 23.0 18.0 22.0 17.5 21.0 20.0 21
VSI 0.0 1.0 0.0 1.0 0.0 0.5 0.0 0.5
T50 (sec.) >30 1.52 >30 1.4 >30 1.86 2.10 1.09
Air Content 
(%)
3 3.2 4 3.4 4.4 3.4 3.0 3.7
Temp. (
o
F) 72 73 76 72 79 74 74 75
Unit Weight 
(lb/ft
3
)
146.8 146.6 146.1 145.3 145.68 145.5 146.4 145
Item
Pl
a
n
t
J
ob Si
t
e
Self-Consolidating Concrete Mixtures
194 
Table 6.9 - Fresh Concrete Properties for Phase V (cont. on next page) 
 
 
 
 
 
 195
9:AL-36-6 SF 10:AL-36-8 SF 11:AL-36-10 SF 12:AL-36-15 SF 13:AL-36-40 SG 14:AL-36-50 SG 14:AL-36-50 SG (LA) 15:AL-36-60 SG
Slump Flow 
(inches)
29 29.5 29 29 26 29 28 30
VSI 1.5 1.5 1.5 1.5 1.5 2.0 1.5 2
T50 (sec.) 1.16 0.76 0.94 1.16 2.29 1.50 1.56 1.12
Wet Slump 
(inches)
1 0.25 0.25 0 0 0.25 0.50 0.75
Slump Flow 
(inches)
22.0 21.5 20.75 22.0 16.0 18.0 21.0 20
VSI 0.0 0.0 0.5 0.5 0.0 1.0 0.5 0.5
T50 (sec.) 1.2 1.01 1.22 1 >30 >30 2.62 2.37
Air Content 
(%)
3.4 3.7 3.5 5.0 4.1 10.5 2.6 17
Temp. (
o
F) 75 76 74 75 83 75 76 76
Unit Weight 
(lb/ft
3
)
145.6 145.2 145.68 144.2 147.8 137.4 148.0 136.92
Item
Pl
a
n
t
Jo
b S
i
t
e
Self-Consolidating Concrete Mixtures
195 
 
 
Table 6.9 ? Fresh Concrete Properties for Phase V (cont.) 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 196
16:AL-36-8 M3 17:AL-36-12 M3 18:AL-36-16 M3 19:AL-36-8 LS 20:AL-36-15 LS 21:AL-36-20 LS
Slump Flow 
(inches)
32 34 31 27.5 27 28
VSI 3 3 3 2 2 2.5
T50 (sec.) 1.15 0.72 0.9 1.44 1.69 1.56
Wet Slump 
(inches)
6 7 6 2 2.5 3.25
Slump Flow 
(inches)
22.0 24.0 22.0 17.5 19.5 21.0
VSI 1.0 1.5 1.0 0.5 0.5 0.5
T50 (sec.) 1.06 0.75 1.09 >30 >30 1.16
Air Content 
(%)
2.9 2.6 2.8 4.5 5 3.7
Temp. (
o
F) 76 77 78 77 76 77
Unit Weight 
(lb/ft
3
)
147.16 145.68 147.4 144.8 144.2 145.6
Item
Pl
ant
Jo
b S
i
t
e
Self-Consolidating Concrete Mixtures
196 
6.6.2 Hardened Concrete Properties  
Compressive Strength: The hardened concrete properties determined for Phase V can be 
seen by looking at Figures 6.27 through 6.38.  Each SCC mixture was compared to a base 
line mixture in order to determine the effect of each method to modify the viscosity on 
the hardened concrete properties.  SCC mixture 1:AL-41-0 VMA was determined to be 
the appropriate base line mixture for all SCC mixtures prepared at a water-to-
cementitious materials ratio of 0.41, while 6:AL-36-33 FA will be used as the base line 
mixture for all SCC mixtures prepared at a water-to-cementitious materials ratio of 0.36.   
Figure 6.27 indicates that the base line mixture with no VMA showed higher 
values of compressive strength at all ages, while the SCC mixture 2:AL-41-2 VMA and 
3:AL-41-10 VMA produced the lowest compressive strength results.  However, this is 
most likely due to the influence of other external factors rather than the incorporation of 
the VMA.  The compressive strengths for these mixtures ranged from 6,800 to 7,500 psi 
at 56-days.   
By comparing the SCC tures 1:AL-41-0 VMA and 2:AL-41-2 VMA to 5:AL-
36-33 (2) FA and 6:AL-36-33 FA in Figure 6.29 it can be seen that the reduction in 
water-to-cementitious materials ratio from 0.41 to 0.36 increased the compressive 
strengths, on average, 2,300 ps 6-days.  This is expected since it is a well known fact 
that the strength is increased as water-to-cementitious materials ratio decreases.  
Furthermore, the results indicate that compressive strength decreased as the percentage of 
fly ash increased.  This is prim to the fact there is only enough calcium 
hydroxide in the paste in which the Class F fly ash can react to form calcium silicates.  
Therefore, higher replacement percentages of fly ash may result in unreacted ash that 
 mix
i at 5
 the 
arily due 
 197
may cause a reduction in the compressive strength.  Additionally, Figure 6.29 shows that 
 
gth, the 
 
typical e, 
cussed in Section 6.6.1, unusually high amounts of entrapped air of 10.5% 
and 17
th 
nd 
n 
 
.  
the 
replacement percentages of fly ash above 50% should not be utilized due to the fact the 
critical 28-day compressive strength of 5,200 psi would not be achieved.  
The results obtained from the compressive strength tests for both the silica fume
and GGBFS mixtures can be seen in Figures 6.31 and 6.33.  Unlike Phase IV where the 
incorporation of the silica fume produced a clear increase in compressive stren
incorporation of the silica fume for these materials did not indicate a significant increase
in compressive strength at 56-days.  This was unexpected since silica fume is known to 
ly improve the microstructure and increase compressive strengths.  Furthermor
Figure 6.31 reveals that the SCC mixture with 15% replacement of silica fume showed a 
decrease in compressive strength compared to the base line mixture.  This decrease in 
compressive strength can be possibly attributed to the fact that the SCC mixture 
contained a higher percentage of entrapped air compared to the base line mixture.  
As dis
% were obtained at replacement percentages of 50% and 60% GGBFS, 
respectively.  It was determined that as the porosity increased the compressive streng
was decreased as shown in Figure 6.33.  For example, mixtures 14:AL-36- 50 SG a
14:AL-36-50 SG (LA) was comprised of exactly the same mixture proportions with the 
exception of the water reducing admixture.  According to Figure 6.33, the reduction i
entrapped air from 10.5% to 2.6% corresponded to an increase of compressive strength of 
at least 4,800 psi at 28 and 56-day.  This is a remarkable increase in compressive
strength, and it shows the significance of the porosity-compressive strength relationship
By examining mixtures 13:AL-36-40 SG and 14:AL-36-50 SG (LA) it appears that as 
 198
replacement of GGBFS increased from 40% to 50%, the compressive strength was 
increased by 1,400 psi and 1,800 psi at 28 and 56-days, respectively.  This is considering
the fact that both mixtures contained reasonably low air contents.  Moreov
 
er, the 
utilizat
ve 
 
 of 
e 
amount
However, 
 
ion of GGBFS was found to increase the compressive strength compared to the 
base line mixture of no less than 1,300 psi at 56-days.   
Figure 6.35 indicates that the use of Micron 3 produced a decrease in compressi
strengths compared to the base line mixture.  The SCC mixtures with Micron 3 
demonstrated an average compressive strength loss of 1,000 psi at 28 and 56-days.  
However, it is thought that this decrease in compressive strength is not a result of the 
Micron 3, but is due to the fact that the Micron 3 was in replacement of cement instead of
fly ash.  As the replacement percentage of Micron 3 was increased the total percentage
fly ash within the SCC mixture increased accordingly.  As higher replacement 
percentages of Micron 3 was introduced into the SCC mixtures, it is probable that th
 of unreacted fly ash was increased resulting in a decrease in compressive 
strength.  This is analogous to the high fly ash mixtures shown in Figure 6.29.  
all Micron 3 mixtures were well above the required critical 28-day compressive strength
of 5,200 psi despite the reduced compressive strength.   
Figure 6.37 shows that the introduction of the limestone filler caused a reduction 
in compressive strength compared to the base line mixture.  Figure 6.37 further reveals 
that the compressive strength of the SCC mixtures is lower as the percentage of limestone 
filler increases.  The reduction in compressive strength is a direct result of the limestone 
filler being inert.  The replacement of cementitious materials by limestone filler is in 
 199
effect raising the water-to-cementitious materials ratio resulting in lower compressiv
strengths.   
e 
Modulus of Elasticity: Figures 6.28, 6.30, 6.32, 6.34, 6.36, and 6.38 present the 
calculated modulus of elasticity values obtained for all SCC mixtures for Phase V.  The
development for the modulus of elasticity is similar to th
 
e strength development provided 
in Figu
 of 
 
this 
res 6.27, 6.29, 6.31, 6.33, 6.35, and 6.37.  Furthermore, Figures 6.27 through 6.38 
indicate that higher modulus of elasticity values were achieved for higher values
compressive strengths.  In order to determine if the calculated elastic modulus for the
concrete mixtures is of typical sound concrete; the calculated modulus of elasticity in 
phase of the research was compared with the ACI 318 (2002) Building Code 
(
ccc
fWpsiE '33)(
5.1
?= ) and the ACI Committee 363 (2002) ?State-of the-Art Report 
on High-Strength Concrete? ( )000,000,1'000,40)( += cfpsiE
c
models.  Figure 6.39 
reveals that the ACI 318 (2002) overestimated the modulus of elasticity for both the 
ODSC and SCC mixtures.  Furthermore, the ACI 318 (2002) was found to increasingly 
overestimate the modulus of elasticity as the compressive strength increased.  This 
finding coincides with ACI Committee 363 (2002) that found that the equation used by 
the ACI 318 (2002) was only valid for compressive strengths up to 6,000 psi.  On the 
other hand, the ACI Committee 363 (2002) equation provided an improved and typically 
conservative estimate for the modulus of elasticity for both the ODSC and SCC mixtures 
as shown in Figure 6.40.  It is believed that the improved and conservative estimation for 
the modulus of elasticity lies in the fact that the equation provided by the ACI Committee 
363 (2002) is valid for compressive strengths from 3,000 to 12,000 psi.   
 
 200
Figure 6.27 ? Compressive Strength vs. Concrete Age for VMA Mixtures 
Figure 6.28 ? Modulus of Elasticity vs. Concrete Age for VMA Mixtures
0
1000
6000
56
Co
r
e
ve S
9000
10000
2000
3000
4000
5000
7000
8000
0 7 14 21 28 35 42 49
Concrete Age (Days)
m
p
s
s
i
t
r
e
ng
th 
(psi
)
1:AL-41-0 VMA 2:AL-41-2 VMA 3:AL-41-10 VMA 4:AL-41-18 VMA
0
2
3
5
6
Concrete Age (Days)
 
1
.0 
x 10 
 p
s
i)
1
4
0 7 14 21 28 35 42 49 56
Modu
lus of
Elast
icity (
6
1:AL-41-0 VMA 2:AL-41-2 VMA 3:AL-41-10 VMA 4:AL-41-18 VMA
 201
 
Figure 6.30 ? Modulus of Elasticity vs. Concrete Age for Fly Ash Mixtu
 
Figure 6.29 ? Compressive Strength vs. Concrete Age for Fly Ash Mixtures 
0
1
2
3
4
5
6
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Mod
u
l
u
s of 
E
l
as
ti
ci
ty (1.
0
 x 10
 6
 ps
i)
5:AL:36-33 (2) FA 6:AL-36-33 FA 7:AL-36-40 FA 8:AL-36-50 FA
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Co
mp
re
s
s
iv
e
 Stre
n
g
t
h
 (
p
s
i
)
5:AL-36-33 (2) FA 6:AL-36-33 FA 7:AL-36-40 FA 8:AL-36-50 FA
res 
 202
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Com
p
ress
i
v
e
 S
t
reng
th 
(p
s
i
)
12000
6:AL-36-33 FA 9:AL-36-6 SF 10:AL-36-8 SF 11:AL-36-10 SF 12:AL-36-15 SF
 
Figure 6.31 ? Compressive Strength vs. Concrete Age for Silica Fume Mixtures 
0
1
2
3
4
5
6
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Mo
du
l
u
s of El
asti
c
i
t
y (1
.
0
 
x 1
0
 6
 psi)
6:AL-36-33 FA 9:AL-36-6 SF 10:AL-36-8 SF 11:AL-36-10 SF 12:AL-36-15 SF
F s igure 6.32 ? Modulus of Elasticity vs. Concrete Age for Silica Fume Mixture
 203
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
14000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Co
mpress
i
ve Stren
g
th
 (p
si)
6:AL:36-33 FA 13:AL-36-40 SG 14:AL-36-50 SG
14:AL-36-50 SG (LA) 15:AL-36-60 SG
 
Figure 6.33 ? Compressive Strength vs. Concrete Age for GGBFS Mixtures  
0
1
2
3
4
5
6
7
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Modulus of E
l
asticity (
1
.0 
x 10 
6 
psi
)
6:AL-36-33 FA 13:AL-36-40 SG 14:AL-36-50 SG
14:AL-36-50 SG (LA) 15:AL-36-60 SG
Figure 6.34 ? Modulus of Elasticity vs. Concrete Age for GGBFS Mixtures 
 204
 
 
Figure 6.36 ? Modulus of Elasticity vs. 
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
12000
C
o
mpr
e
ss
i
ve St
r
e
ngt
h 
(
p
si
)
6:AL-36-33 FA 16:AL-36-8 M3 17:AL-36-12 M3 18:AL-36-16 M3
Figure 6.35 - Compressive Strength vs. Concrete Age for Micron 3 Mixtures 
0
1
2
3
4
5
6
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
M
o
d
u
lu
s
 o
f
 Ela
s
t
ic
ity
 (1
.0
 x
 1
0
 6
 p
s
i)
6:AL-36-33 FA 16:AL-36-8 M3 17:AL-36-12 M3 18:AL-36-16 M3
Concrete Age for Micron 3 Mixtures 
 205
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
C
o
mpr
essi
ve Str
e
ngt
h
 (psi
)
6:AL-36-33 FA 19:AL-36-8 LS 20:AL-36-15 LS 21:AL-36-20 LS
Figure 6.37 ? Compressive Strength vs. Concrete Age for Limestone Mixtures 
 
0
1
2
3
4
5
0 7 14 21 28 35 42 49 56
Concrete Age (Days)
Mo
dulus of Elasticity (1
 x 
10 
6
 p
s
i)
6
6:AL-36-33 FA 19:AL-36-8 LS 20:AL-36-15 LS 21:AL-36-20 LS
Figure 6.38 ? Modulus of Elasticity vs. Concrete Age for Limestone Mixtures 
 206
 
Figu    
                        Equation for Phase V  
Figure 6.40 ? Predicted vs. Measured Elastic Modulus According to ACI 363 (2002)  
                    Equation for Phase V 
re 6.39 ? Predicted vs. Measured Elastic Modulus According to ACI 318 (2002)
0
1
2
3
4
5
6
0123456
Measured Elastic Modulus (1.0 x 10 
6
 psi)
P
r
e
d
ic
te
d E
l
a
s
t
i
c
 M
odulus
 (1.
0
 x
 1
0
 
6
 psi
)
-10% Error
+10 Error
Line of Equality
0
1
2
3
4
5
6
0123456
Measured Elastic Modulus (1.0 x 10 
6
 psi)
P
r
edic
t
e
d Ela
s
tic
 
Modulus (1.0 x 10 
6
 psi)
+10% Error
-10% Error
Line of Equality
  
 207
6.6.3 Effect of VMA on Fresh Concrete Properties  
 The results in Table 6.9 indicate that the polyethylene glycol VMA was found not 
to significantly influence the viscosity of the SCC mixtures even at high dosage amounts.  
However, results may suggest that the incorporation of the polyethylene glycol VMA 
provided a slight increase in stability compared to the SCC mixtures with similar mixture 
proportions without VMA at higher values of slump flow.  Furthermore, this VMA could 
possibly be used to overcome deficiencies in mixture constituents in everyday batch plant 
operations.  To study the effects of this viscosity agent on the stability of SCC mixtures 
when subjected to inaccurate moisture corrections, mixing water was added to or 
deducted from a base line mixture.  This base line mixture was 5:AL-36-33 2
.
FA with the 
following modifications.  The first modification is the incorporation of the VMA.  Each 
testing point consisted of one m
oz/cwt to 8 oz/cwt for all concrete mixtures.  The results in Table 6.10 and Figure 6.41 
indicate that at the water content equal to the base line mixture the VMA appears to have 
minimal effect on the slump flow, stability, or viscosity.  However, as additional water 
was added to the base line mixture, the stability of the mixture was found to be increased 
with the addition of VMA.  The increase in stability can be attributed to the lower slump 
flow values for the SCC mixtures with VMA at +10 and +20 lb/yd
3
.  This decrease in 
slump flow values for the SCC mixtures that incorporated VMA is most likely due to the 
fact the VMA is rendering the mixture more robust as excess water is released by the 
HRWRA.  At lower slump flow values and lower free water contents the VMA was 
found to be ineffective in increasing the stability of the SCC mixtures.  The results from 
ixture that incorporated the 2 oz/cwt of VMA and one 
mixture without the VMA.  Secondly, the HRWR admixture dosage was reduced from 10 
 208
the study indicate that the use of this type of VMA can decrease the sensitivity of the 
SCC mixtures due to inaccurate moisture corrections.  However, at lower slump flow 
values the use of the polyethylene glycol VMA may not provide an increase in stability.  
When low water-to-cementitious materials ratios are used and the SCC mixtures are 
placed at lower slump flow values, the incorporation of this type of VMA may not be 
necessary.  On the other hand, if moisture variability can not be properly controlled and 
the SCC mixtures are placed at higher slump flow values the use of a VMA can be 
beneficial.   
 
 
Table 6.10 ? Tabulated Results of the Effect of VMA on Fresh Concrete Properties  
 
Wet Slump 
(inches) 
Weight 
(lb/yd
3
)
Conte
(%)
Unit 
Air 
Fresh Properties Slump Flow
nt 
Temp. 
(
o
F)
Diameter 
(inches) 
T50 (sec) VSI
20 lb/y
3
+10 lb/yd  without VMA
2
3
+0 lb/yd   with VMA
3
-20 lb/yd  without VMA
+ d
3
 without VMA
9 147.9 2.7 75 31 0.44 3
+20 lb/yd   with VMA
8 146.8 4 75 28 0.9 2
3
5 143.64 5 76 27.5 0.96 2.5
+10 lb/yd
3
  with VMA
5 142.2 3.5 74 26 1.38
+0 lb/yd  without VMA
2 1/2 144.6 5.1 75 25.25 1.56 1.5
3
2 145.4 3.9 75 25 1.69 1
-10 lb/yd
3
 without VMA
1 1/4 145.5 3.9 73 24.5 1.47 1
-10 lb/yd   with VMA
1/4 144.9 4.2 74 23 2.35 1
3
0 143.7 5 74 21.5 4.75 0
-20 lb/yd
3
  with VMA
0 145 4 76 20.5 3.97 0
 209
 
Figure 6.41 ? Graphical Results of the Effect of VMA on Fresh Concrete Properties
 
 
 
6.7 SUMMARY OF RESEARCH FINDINGS 
 
? Based on the results of this research, it is concluded that the early or delayed 
addition of the HRWRA has no considerable effect on the workability 
characteristics of the SCC mixtures. 
? It was
0
25
30
Unit Water Content (lb/yd
3
)
S
l
ump F
l
o
w
 (
i
nc
he
s)
5
10
15
20
30
35
-30 -20 -10 0 10 20
VMA Used
VMA Not Used
B
a
s
e
 
M
i
x
ur
 Line
t
e
Additional Water Deducted Water 
 
 determined that obtaining a water slump before the addition of the 
HRWRA was suitable for not only ensuring correct moisture corrections, but also 
? It was found that obtaining a water slump under real field conditions required a 
considerable increase in time compared to laboratory conditions.   
in determining appropriate mixture proportions for the SCC mixtures. 
 210
? The ODSC mixtures prepared for this research were found to be within the 
specified range of slump values at placement in addition to demonstrating typical 
workability characteristics for wet-hole construction. 
? The incorporation of the 4 oz/cwt mid-range water reducing admixture PolyHeed 
1025 seems to help maintain the workability of the SCC mixtures better than 
those that contained only Glenium 3030 NS. 
? The ODSC mixtures demonstrated a higher degree of bleeding compared to the 
SCC mixtures prepared at the same water-to-cementitious materials ratio.   
? It was concluded that the HRWRA Glenium 3030 NS was the primary cause of 
the increased air content for the SCC mixtures.   
? The results from this research indicate that at similar slump flow values the 
viscosity of the SCC mixtures was not increased at high dosage amounts of VMA.  
However, the results suggest that the VMA may provide a slight increase in 
stability at higher values of slump flow with increasing VMA dosage. 
? At lower slump flow values such as those representing the job site testing; the 
VMA appears to have no effect on the stability of the SCC mixtures.   
? The results show that the use of VMA could possibly be used to overcome 
deficiencies in mixture constituents in everyday batch plant operations, which 
mainly consist of inaccurate moisture corrections. 
? Based on the materials and mixtures proportions used for Phase V, the 
incorporation of high amounts of fly ash, Micron 3, or limestone filler as the 
method to modify the viscosity was found not to increase the viscosity of the SCC 
mixtures by evidence of the T
50
 times.  
 211
? The incorporation of the silica fume provided no increase in viscosity by evidence 
of the T
50
 times.  However, the utilization of the silica fume was found to improve 
the stability of the mixtures.  
? The incorporation of GGBFS provided a reduction in the water slump and showed 
a higher degree of stability at the batch plant compared to mixtures prepared with 
fly ash and at the same water-to-cementitious materials ratio.  In addition, the 
incorporation of the GGBFS seems to slightly increase the T
50
 times compared to 
the silica fume mixtures and the fly ash mixtures at similar slump flow values. 
? The SCC mixtures prepared at a water-to-cementitious materials ratio of 0.41 
demonstrated slightly lower compressive strengths compared to those of the 
ODSC mixtures.  It is concluded that this is a result of the higher replacement 
percentage of cement by fly ash for those mixtures.  
ground granulated blast furnace slag (GGBFS) can provide an increase the 
 
? er caused a reduction in compressive 
duction 
ising the 
? At a constant water-to-cementitious materials ratio the use of the silica fume or 
compressive strength.   
? High replacement percentages of fly ash may result in unreacted ash that may
cause a reduction in the compressive strength. 
The introduction of the limestone fill
strength compared to the base line mixture.  The primary reason for the re
in compressive strength is a direct result of the limestone filler being inert.  The 
replacement of cementitious materials by limestone filler is in effect ra
water-to-cementitious materials ratio resulting in lower compressive strengths.   
 212
? The SCC mixtures prepared at the same water-to-cementitious materials rati
the ODSC mixtures demonstrated a reduction in RCPT values at 91 and 365-days.
The RCPT values obtained at 91-days for the SCC and
o as 
     
?  ODSC mixtures were 
 to the formation of C-S-H and the 
CC mixtures.   
 
found to decrease with time.  This is because as the hydration process proceeds, 
the interconnected pores that were present at 91-days are being filled by the 
continuous and overall increase in volume due
continuous grow of the calcium hydroxide within the capillaries pores, which 
lowered the RCPT values at 365-days.   
? The introduction ground granulated blast furnace slag (GGBFS) was found to 
increase the RCPT values compared to the (FA) S
 213
 
 
 
 
CHAPTER 7  
 
PROPOSED EXPERIMENTAL FIELD STUDY  
 
7.1 INTRODUCTION 
 The primary purpose of the field study is to evaluate the use of SCC as a viable 
material to be used in drilled shaft construction.  This field study will provide a means of 
comparison between self-consolidating concrete and ordinary drilled shaft concrete for 
both fresh and hardened properties under simulated field conditions.  A brief discussion 
of the proposed field study is shown below.  This discussion includes test shafts, fresh 
concrete property testing, hardened concrete property testing, placement monitoring, 
testing of non-exhumed shafts, testing of exhumed shafts, and instrumentation.  The 
proposed site for this field study is located approximately 1.25 miles southeast of 
Nichols, South Carolina as shown in Figure 7.1.  Unfortunately, due to long construction 
delays and design set backs the researcher will have very limited involvement in the field 
study.  As a result, changes to this proposed field study below will almost certainly occur 
without the researcher?s knowledge.  It is recommended that the actual construction 
details and concrete testing that occurred for this field study be obtained from the 
research advisors.  Furthermore, all testing procedures listed in this chapter should be 
conducted using current ASTM standards.  
 
 
 214
 
 
Project Location 
 
 
 
 
 
 
 
 
 
Figure 7.1 ? Proposed Field Site (courtesy of Mapquest 2005) 
 
7.2 TEST SHAFTS  
? Day 1 Experimental Casting: 2 - 6.0 ? X 30 ft test shafts made with ordinary 
drilled shaft concrete.  One test shaft consisting of ordinary drilled shaft concrete 
shall be exhumed at 28 days or later after placement for visual inspection and 
testing.  
? Day 2 Experimental Casting: 2 - 6.0 ? X 30 ft test shafts made with self-
consolidating concrete (SCC).  One test shaft consisting of SCC shall be exhumed 
at 28 days or later after placement for visual inspection and testing.  
 
7.3 FRESH CONCRETE PROPERTY TESTI
 
? Slump Test  ASTM C 143 (1998)  
o Performed on all ordinary drilled shaft 
and time of placement.  
 215
NG  
concrete mixtures directly after mixing 
o The slump of the ordinary drilled shaft concrete mixtures, at the time of 
placement, shall be 8 ? 1 inches. 
o Performed periodically on all ordinary drill shaft concrete mixtures for a 
duration of no less than 5 hours after batching (slump retention). 
? Slump Flow Test   
o Performed on SCC mixtures directly after mixing and time of placement.  
o The slump flow of the SCC mixtures, at the time of placement, shall be 21 ? 3 
inches. 
o Performed periodically on all self-consolidating concrete mixtures for a 
duration of no less than 5 hours after batching (slump flow retention). 
? Total Air Content and Unit Weight ASTM C 138 (1998) 
? J-Ring Test  
? Segregation Column  
? Bleeding Test ASTM C 232 (1998) 
? Setting by Penetration Resistance ASTM C 403 (1998) 
o 6 ? x 6 inch cylindrical specimens of mortar shall be obtained by wet sieving. 
 
7.4 HARDENED CONCRETE PROPERTY TESTING 
 
? Compressive strength, (f
c
): ASTM C 39 (1998) and Elastic Modulus, (E
c
): ASTM 
C 469 (1998) 
o 3 ? 6 ? x 12 inch molded specimens shall be cast per testing age. 
o The curing of the specimens shall be done in accordance with ASTM C 31 
(1998). 
o The specimens are to be demolded no earlier than 2 x initial set.   
o The specimens should be tested at ages of 3, 7, 14, 28, and 56 days.  
? Drying Shrinkage: ASTM C 157 (1998) 
o 3 ? 3 x 3 x 12 inch molded specimens shall be cast per mixture.  
o The shrinkage bars shall be placed in a lime saturated bath for the first 28 
days.  Afterwards, the specimens shall be removed from the lime bath and 
placed in air storage. 
 216
o The specimens are to be demolded no earlier than 2 x initial set.   
o The specimens should be tested at 1, 2, 3, 7, 14, 28, 56, 91, 180, and 365 
days after removal from lime saturated bath.  
? Permeability: ASTM C 1202 (1998) 
o 3- 4 ? x 8 inch molded specimens shall be cast per testing age. 
o The specimens are to be demolded no earlier than 2 x initial set. 
o The curing of the specimens shall be done in accordance with ASTM C 31 
(1998).   
o The specimens should be tested at ages of 91 and 365 days. 
 
7.5 PLACEMENT MONITORING  
 
? The elevation difference between the inside and outside of the rebar cage shall be 
determined by the use of plumb-bobs.  
? Coloring of various concrete loads for the exhumed shafts shall be as follows:  
o 1
st
 load shall be of normal color followed by red then black loads. 
o The red load shall be placed normally followed by a 60 minute delay 
simulating construction difficulties.   
 
7.6 TESTING OF NON-EXHUMED SHAFTS 
 
? Cores  
o Location: Cores should be taken at locations of 5, 15, and 25 feet below 
the surface of the non-exhumed test.  
? Compressive strength, (f
c
): ASTM C 39 (1998), Elastic Modulus, (E
c
): ASTM C 
469 (1998),  
o Testing Age: 56 days (Coring should occur at 51 days) 
o Size: 4 inch core diameter 
o Specimens: 4 x 8 inch 
o Treatment: In accordance with ACI 318 (2002) Section 5.6.5 
? Permeability ASTM C 1202 (1998)  
o 3 specimens  
o Cored at 51 days and tested at 91 day 
 217
o Size: 4 ? x 2 inch disks  
 
7.7 TESTING OF EXHUMED SHAFTS  
 
? Cut Cross-Sections:  
o Cross sections shall be cut at locations of 5, 15, and 25 below the surface 
of the exhumed shaft by means of a specialized wire saw. 
o Visual Assessment of aggregate, coloring of loads, and void distribution 
shall be conducted for all cut cross-sections.   
o Impact-echo mapping of cross-section?s density shall be performed for all 
cut cross-sections.   
o Extract one 4 ? x 8 inch core from each cut face for calibration of impact-
echo.  
 
7.8 INSTRUMENTATION  
? Temperature Profiles using I-Buttons (non-exhumed shafts) 
o I-Buttons should be fixed firmly to steel dowels and placed in 5 feet intervals 
vertically. 
o The location of the steel dowels shall be 2.5, 7.5, 12.5, 17.5, 22.5, and 27.5 
feet below the surface of the shaft. 
o There shall be 9 I-Buttons per dowel and 54 I-Buttons per shaft (Total = 108). 
o Data Collection: The sample interval for the I-Buttons shall be 15 minutes for 
the first 28 days after placement.  After the data has been collected for the first 
28 days, the I-Buttons are to be reset at a sample interval of 4 hours for a year.   
? Pressure Profile using Load Cells (non-exhumed shafts) 
o There shall be 6 load cells per shaft located at 2.5, 7.5, 12.5, 17.5, 22.5, and 
27.5 feet below the surface of the shaft. 
? Cross-Hole Sonic Logging (non-exhumed shafts) 
o Cross-hole sonic logging should be conducted at locations of 5, 15, and 25 
feet below the surface of the shaft. 
 218
 
 
 
 
CHAPTER 8 
 
SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS 
 
8.1 INTRODUCTION 
 
 The laboratory testing program was executed to determine if self-consolidating 
concrete can be used as a viable material for drilled shaft construction.  The primary 
objectives of this research were to identify appropriate testing techniques, identify 
characteristics for this specific application, and potential problems or concerns with the 
use of SCC in drilled shaft construction.  Furthermore, the laboratory testing program 
examined the difference between ordinary drilled shaft concrete and SCC for both fresh 
and hardened properties.  The fresh properties include filling ability, passing ability, 
segregation resistance, workability over time, bleeding characteristics, and controlled 
setting, while the hardened properties included the comparison of the compressive 
strength, elastic modulus, and drying shrinkage.  It is hopeful that this research will lead 
to additional interest in this topic from state and national transportation agencies so that 
further research in this area can be conducted.  This chapter will present the summary and 
conclusions drawn from this research while offering recommendations based on the 
summary and conclusions.   
 
 8.2 SUMMARY AND CONCLUSIONS 
 The laboratory testing of the fresh and hardened properties for both the ODSC 
and SCC mixtures provided insight into the use of SCC for drilled shaft applications.  
219 
The results provided in Chapter 6 were thoroughly examined and conclusions were drawn 
from these results.  The following section presents the summary conclusions drawn from 
this research testing program. 
? The use of set-retarding admixtures can significantly increase the time in which a 
concrete mixture will remain workable.  For drilled shaft applications, the dosage 
of set-retarding admixture should be adjusted to provide an extended initial set 
necessary to ensure that the workability of the concrete mixture is maintained for 
the duration of the pour and to allow for any construction delays in concreting and 
removal of the temporary casing after concreting is completed. 
? For a given dosage of set-retarding admixture, concrete mixtures can experience 
faster initial set times and increased slump loss when exposed to higher 
temperatures compared to the laboratory conditions. 
?  This research shows that merely estimating the additional amount of set-retarding 
admixture needed in hot weather conditions is not a sufficient measure to ensure 
that proper retained workability and set times are achieved.  The amount of 
retarding admixture should be based on trial mixes under simulated conditions.  
? Results indicate that SCC mixtures can experience an increased workability loss 
compared to ODSC mixtures when subject to similar mixing conditions.  The rate 
and amount of workability loss depends on the initial workability conditions, 
degree of agitation, rotational speed of the mixing drum, and duration of mixing.   
? The SCC mixtures prepared for this research provided a considerable increase in 
workability at placement compared to the ODSC mixtures.  This enhanced 
220 
workability may be capable of overcoming placement difficulties associated with 
tremie placing concrete and congested rebar cages.   
? SCC mixtures are more inclined to have a larger change in workability for the 
same amount of time compared to the ODSC mixtures.  
? The Slump Flow, T
50
, and J-Ring tests were deemed acceptable quality control 
procedures for both laboratory and field conditions for drilled shaft applications.   
? It is a must that the static stability of the SCC mixture be part of the determination 
of the VSI rating.  This should be done by observing the SCC mixture in the 
wheelbarrow or mixing drum directly after the completion of the slump flow test.  
? It is concluded that the segregation column can be used to provide a quick and 
valuable testing procedure for laboratory purposes to determine the probability of 
a SCC mixture to segregate, especially at higher values of slump flow.   
? The critical sand-to-aggregate ratio for these materials for passing ability and 
segregation resistance is 0.44 or higher.  The possibility of blockage and 
segregation may be increased at sand-to-aggregate ratios below 0.44.  
? The SCC mixtures exhibited increased stability as the water slump and water-to-
cementitious materials ratio was reduced, which is more apparent at higher values 
of slump flow. 
? The ODSC mixtures demonstrated a higher degree of bleeding compared to the 
SCC mixtures prepared at the same water-to-cementitious materials ratio. 
? If the moisture variability at the batch plant can be properly controlled and since 
the SCC mixtures for this research are placed at lower values of slump flow (18 to 
221 
24 inches), it is the opinion of the author that very workable and stable SCC 
mixtures can be achieved without the use of the polyethylene glycol VMA.   
? It was concluded for this research that since the fine and coarse aggregates were 
high quality and the aggregate volume fraction was not drastically different, the 
modulus of elasticity of the SCC mixtures was not significantly affected by the 
varying sand-to-aggregate ratio, which ranged from 0.40 to 0.48.   
? The results from this research indicate that with these materials and mixture 
proportions, the equation provided by ACI 318 (2002) typically overestimated the 
modulus of elasticity especially at higher values of compressive strengths.  
Conversely, the equation provided by the ACI Committee 363 (2002) was found 
to provide an improved and conservative estimate of the modulus of elasticity.   
? The water-to-cementitious materials ratio appeared to be the main factor 
influencing the drying shrinkage.  The results indicate that the reduction in water-
to-cementitious materials ratio decreased the concrete specimen?s tendency to 
shrink. 
? It can be concluded that the coefficient of permeability decreases as the water-to-
cementitious materials ratio is reduced.  
? It can be concluded that the introduction of silica fume can considerably reduce 
the permeability of concrete.   
 
8.3 RECOMMENDATIONS  
? Due to the time-dependent effects of the HRWR admixture, it is recommended 
that laboratory mixing procedures account for transportation time and the HRWR 
222 
admixture be adjusted to account for the transportation time so that SCC mixture 
will meet the specified quality control limits upon arrival to the job site.  
? It is recommended that field adjustments to the chemical admixtures at the job site 
be avoided; rather all efforts should be made to correctly batch the chemical 
admixtures at the source of mixing. 
? It is highly suggested that trial mixes be conducted under simulated conditions in 
order to determine the appropriate set-retarding admixture dosage and proper 
workability retention is achieved.   
? It is suggested that the slump flow and J-Ring test be used as quality control test 
for the SCC mixtures in both the laboratory and field settings.  The segregation 
column test can be used for laboratory purposes.   
? In order to overcome placement problems associated with ODSC mixtures it is 
recommended that the SCC mixtures be placed at a slump flow ranging from 18 
to 24 inches with a VSI rating of 1 or less.  It is the opinion of the author that 
these quality control limits will provide a SCC mixture with sufficient flowability, 
workability, and stability for both dry and wet-hole construction.   
? The following suggestions are offered to overcome issues associated with 
congested rebar cages.  Firstly, the use of small well-graded rounded river gravel 
should be utilized in applications where the rebar cages are congested.  In regards 
to the SCC mixtures, it is suggested that the use of a small well-graded rounded 
river gravel with a #7 gradation be used to ensure high passing ability and reduced 
possibility of segregation.   
223 
? It is recommended that water-to-cementitious materials ratios of 0.36 to 0.40 be 
utilized for drilled shaft applications. 
? In order to help reduce the amount of bleed water generated the following 
suggestions are offered: 
1. Use large amounts of supplementary cementitious materials to reduce the 
amount of free water 
2. Air entrainment 
3. By reducing the free water content or water-to-cementitious materials ratio 
4. Utilizing of new polycarboxylate ester based mid and high range water 
reducing admixtures 
5. Presence of adequate proportions of very fine aggregate particles, which  can 
consist of raising the sand-to-aggregate ratio 
6. The use of a binding type VMA 
? If a low permeability-high durability drilled shaft concrete mixture is required in 
areas prone to chemical attack, a low water-to-cementitious materials ratio and/or 
the incorporation of fine material, such as silica fume, should be used to provide 
the necessary durability.   
? It is recommended that the SCC mixture 9:36-44 FA be utilized for the field study 
to be conducted in South Carolina.  
? Establish a ?high performance concrete criteria? for drilled shaft construction 
based on the following: 
1. Workability requirements  
2. Shaft size 
3. Congestion of the rebar cages 
4. Typical aggregate size and type  
5. Retained workability requirements 
6. Avoidance of segregation & bleeding  
224 
 
 
 
 
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