Empirical model for predicting the resilient modulus of frozen unbound road materials using a hyperbolic function

Abstract

Abstract The resilient modulus (MR) is a key parameter required in the mechanistic-empirical methods, which are widely used for the rational design of pavement structures. However, experimental determination of the MR is expensive and time-consuming since it requires elaborate equipment for testing and trained personnel. Due to this reason, several researchers have proposed models for predicting the MR of unbound road materials that take into account the influence of wetting and drying conditions. However, the presently available models in the literature have some limitations for the prediction of the MR of these materials at a frozen state. In this paper, a model with two-constants is proposed for predicting the variation of the MR with subzero temperature for unbound road materials exploiting the hyperbolic shape of the frozen resilient modulus - subzero temperature relationship. Experimental data on eighteen different unbound road materials including both fine- and coarse-grained soils, and under both saturated and unsaturated conditions, were used to validate the proposed model. It is shown that the proposed model can reasonably well-predict the MR of the investigated soils that are in a state of frozen condition. More investigations on different types of soils would be useful for better understanding the strengths and limitations of the proposed model. In addition, the effect of stress should be incorporated for further improving the model.