Investigation of motion of coarse aggregates in asphalt mixture based on virtual simulation of compaction test

Abstract

ABSTRACTBased on the discrete element method, the paper conducted a virtual simulation of static compaction test to investigate the motion of coarse aggregates within asphalt mixture. Considering the irregular polyhedral morphology and elastic property of coarse aggregates, the viscoelastic property of asphalt mastic and air voids with a random distribution, a three-dimensional compaction model of asphalt mixture was built and verified. Several indicators including displacement increment (DI), translational and motion angle were proposed to quantitatively analyse the evolution of aggregates at different compaction levels. It is found that the motion of aggregates is closely related to the external loading orientation and the static compaction method is not effective in allowing aggregates moving in horizontal orientation. The internal structure of asphalt mixture can affect the movement behaviour of aggregates. The motion angle in two dimensions is directly correlated to the reference plane, and the relationship between loading orientation and the reference plane can affect the magnitude of motion angle. There is a positive correlation between the DI of aggregates and compaction level in loading direction. The micromechanical compaction model can clarify the mechanism of asphalt mixture well.