Strength Assessment of Soil Cement

Abstract

Soil cement is a mixture of soil, portland cement and water that, once compacted and cured, forms a strong and durable pavement base. Construction practices and variance among core strength data have led to questions concerning proper quality control practices and testing protocol regarding soil cement. One of the main difficulties in soil-cement base construction is the strength assessment of the fully cured soil-cement base roadbed, which leads to the following questions: is it possible to approach strength testing of soil cement like conventional concrete, and is it plausible to use field-molded samples as control samples to evaluate the strength of soil-cement base? In order to answer these questions, a field and laboratory testing program was developed to evaluate the effects of curing, capping, and length-to-diameter ratio on compressive strength of soil-cement cylinders. A draft test procedure was developed to prepare and test cylinders molded in the field or laboratory. The results from this research are aimed at providing guidance to transportation agencies when specifying strength assessment parameters for soil-cement base. Based upon the findings of this research study, it is recommended that soil-cement cylinders made in a manner compliant to the proposed draft specification be considered for quality assurance for the strength assessment of soil cement as delivered to the construction site.