Creep and Shrinkage Behavior of Concrete in Segmental Bridge Construction

Abstract

This thesis is aimed at quantifying the shrinkage and creep behavior of the I-59/I-20 segmental bridge located in downtown Birmingham, Alabama. Also, two laboratory concrete mixtures of different coarse aggregate types were produced at Auburn University. These mixtures were used to evaluate the significance that coarse aggregate type plays in creep and shrinkage behavior when all other constituent materials are held constant and mixed under laboratory conditions. For the samples that were collected in the field, the creep behavior for the following four loading ages were investigated: 7 days, 28 days, 91 days, and 182 days. For the two laboratory mixtures, the creep behavior for the following loading ages were investigated: 7 days, 28 days, and 91 days. Both the field and laboratory mixtures were cured at elevated temperatures. The field specimens were cured in the same manner as the actual segment from which they were sampled from, and the laboratory specimens were match-cured at a temperature cycle similar to one that the field specimens were exposed too. Also, the creep and shrinkage strains that were monitored for the duration of this project were then compared to predicted values using five different models that are common in design of many concrete structures of today. These models include the AASHTO LRFD 2017, ACI 209, CEB MC 2010, GL 2000, and the B3 Model. Also, after evaluating the accuracy of the each of the prediction methods previously mentioned, the method that produced the overall best results was subjected to a calibration process. After careful evaluation of all collected creep and shrinkage data for the field-mixed concrete, it was noticed that the concrete that was sampled and tested on July 9, 2018 exhibited smaller creep and shrinkage strains as compared to the concrete that was sampled and tested on April 10,2018. The measured compressive strength and modulus of elasticity also improved for each loading age for the concrete that was sampled on July 9, 2018 as compared to concrete that was sampled on April 10, 2018. Also, it was discovered that the substitution of coarse aggregate type did not have a significant impact on creep and shrinkage behavior after evaluating all creep and shrinkage data for the laboratory-mixed concrete.