Resilient Moduli Characterization of Cement-Treated Silt at High Compaction Energy Conditions

Abstract

The design and performance of a flexible pavement depend on several parameters, and one of the important parameters is the resilient modulus ( MR) of subgrade soil. The resilient modulus has been used to characterize the subgrade soil behavior under repeated traffic loading conditions. Cement is widely used by defense and highway agencies to stabilize and improve the performance of problematic natural subgrade soils. Several research studies were conducted on the resilient behavior of cement-treated sandy and clayey soils compacted at standard Proctor energy conditions. However, there is a knowledge gap in understanding of the resilient behavior of cement-treated silt compacted at higher compaction energy conditions. Therefore, the current research study assessed the resilient moduli properties of cement-treated silt compacted at higher energy conditions using a modified Proctor energy effort. Subsequently, repeated load triaxial (RLT) tests were conducted on these soil specimens prepared at different cement dosages and curing periods to study their influence on soil stiffness. Untreated soil specimens exhibited stress-softening behavior with an increase in deviator stress, whereas cement-treated soil specimens exhibited stress-hardening behavior. The resilient modulus increased with an increase in cement dosage. Further, regression analyses were conducted on RLT test results using two- and three-parameter models to determine the respective regression constants. It was observed that the three-parameter model, which uses bulk and octahedral shear stresses, exhibited an excellent fit with the experimental data and provided the best predictions of resilient modulus properties of the cement-treated silt at high compaction energy conditions.