Modified two-phase micromechanical model and generalized self-consistent model for predicting dynamic modulus of asphalt concrete

Abstract

The dynamic modulus (E*) of asphalt mixture is a critical parameter when analyzing the performance of asphalt layers and pavements. The laboratory test, though directly obtaining such parameter, consumes a lot of time and energy. Also, when raw materials change, the extensive work has to be taken repeatedly. Thus, analytical and numerical methods on predicting asphalt mixture E* were developed. Micro-mechanical models have significant advantages due to the calculation efficiency compared with the finite element methods and discrete element methods. In this study, a modified two-phase micromechanical model (MTPMM) and a generalized self-consistent model (GSCM) considering voids effect in the asphalt concrete are both adopted to predict asphalt mixture E*. It is found that the equivalent Poisson’s ratio of asphalt mixture is of vital importance for prediction accuracy of the MTPMM. Analytical results from both MTPMM and GSCM matched well with the experimental results. However, the GSCM underestimates E* in the lower loading frequencies while overestimates in higher loading frequencies. The numerical solution from the random aggregate model predicted E* matching well with that from MTPMM, but is slightly different from GSCM, ensuring that two analytic models are sufficient to predict the dynamic moduli of asphalt mixture.