3D Discrete Element Method Modeling of Recycled Asphalt Mixture Considering Coarse Aggregate Morphology

In this research, a numerical simulation of recycled asphalt mixture was conducted, considering the morphology of irregular virgin and reclaimed asphalt pavement (RAP) aggregates using the 3D discrete element method (DEM). The shape of coarse aggregates was accurately captured through X-ray computed tomography and image processing technology. Clumps representing realistic coarse aggregates were generated in the DEM model based on aggregate gradation. The linear model, Burgers model , and linear parallel bond model were employed in the DEM model of the asphalt mixture. Laboratory indirect tensile (IDT) test results were compared and analyzed against those of the virtual specimen, confirming the accuracy of the established DEM model. The study preliminarily evaluated the influence of bonding parameters and RAP aggregate morphology on the DEM simulation. The findings revealed that both bonding parameters and RAP aggregate morphology significantly affect the outcomes of the virtual IDT test. The peak force of the IDT specimens increased as bonding parameters increased, while a rounder shape or poorer angularity of coarse aggregates tended to decrease the IDT strength of the asphalt mixture.