Simulation of wheel tracking test for asphalt mixture using discrete element modelling

This study investigated the simulation of wheel tracking test and the high-temperature rutting behaviour of an asphalt mixture by using the discrete element method (DEM). Based on the DEM software named as Particle Flow Code in three dimensions (PFC3D), a micromechanical model of an asphalt mixture composed of coarse aggregates, asphalt mastic, and air voids was built and a two-dimensional virtual wheel tracking test was simulated. Based on the virtual wheel tracking test, the distribution of displacement and contact forces within test specimen were analysed. It is proved that the built virtual wheel tracking test can capture the rutting deformation caused by the combination of densification and lateral flow deformation. It is also indicated that, within an asphalt mixture, the aggregate skeleton is the main bearing body for the compressive forces, while the compressive and tensile forces between aggregate and mastic are severer than that within asphalt mastic. It is important to guarantee the stability of the aggregate skeleton and the bonding strength between aggregate and asphalt mastic to resist rutting deformation.