Determination of Elastic and Plastic Subgrade Soil Parameters for Asphalt Cracking and Rutting Prediction

Abstract

A preliminary step in the prediction of rutting and cracking in a number of accelerated loading facility trials in Australia is presented. The results of laboratory repeated load triaxial tests were used to characterize the residual and resilient deformation of a silty clay subgrade material. The analysis of permanent deformation indicated that the well-known model Ep, = INSc can be used to estimate the accumulated strain at any number of loading cycles. The parameter S (the slope of the line in a plot of log Ep-log N) was found to be independent of stress and density, but very small increases were observed as moisture content increased. The parameter I (the intercept in a plot of log Ep-log N) was found to be most sensitive to deviator stress. The test results also indicated that I increased with increasing moisture content and decreased as dry density increased. The analysis revealed that an exponential relationship existed between I and deviator stress. This relationship was used to develop a constitut...