Experiment study on dynamic resilient modulus of the compacted clay under moisture content fluctuation

Subgrade soils are important materials to support highways. For the past few decades，the resilient modulus (MR) has been used for characterizing the stress-strain behavior of subgrades subjected to repeated vehicle loadings. It is well known that the moisture content has an important impact on MR of clay. In fact, the moisture of subgrade does not keep stable but fluctuates seasonally. In this paper, the impact of moisture content fluctuation on MR of compacted clay was investigated by laboratory experiment. It is shown that, MR of compacted clay decreases significantly with the moisture content fluctuation cycles, and the bigger fluctuation amplitude is, the lower MR is. So the reduction factor of moisture fluctuation is proposed to reflect this impact on the long term performance of subgrade.