Drained Shear Strength of Over-Consolidated Compacted Soil-Cement

Abstract

The use of cement as an additive to natural soil has been practiced for a long time in engineering projects. Chemical bonds generated as the result of cement hydration and pozzolanic reactions have been responsible for the increase in strength of cemented soils. The purpose of this research is to evaluate the effect of cement on residual strength of overconsolidated soil. Drained shear strength of overconsolidated compacted soil and soil-cement specimens consisted of 50% bentonite, 50% Aeolian sand with 3% by dry weight cement in as compacted (unsheared or intact); precut (residual) conditions were measured in a direct shear device after varying curing time. The cementation that occurred because of the addition of cement and the increase of curing time caused a remarkable increase of mobilized drained shear strength in both intact and residual conditions. A remarkable increase in cohesion intercepts c′, a negligible decrease in ϕ(oc)′ in intact condition, a negligible cohesion and noticeable increase in ϕr′, and a decrease in drained shear strength parameters m and mr occurred as a result of cement addition and increased curing time.