Fundamental Mechanics of Asphalt Compaction through FEM and DEM Modeling

The compaction of asphalt concrete is the last step in controlling the quality of pavement. Tremendous information on the mixture's characteristics, segregation, and fundamental properties of asphalt concrete demonstrates itself in the compaction process. An understanding of the fundamental mechanisms of compaction will help better control the quality of asphalt concrete pavement. This paper presents the investigation of the compaction mechanics using both Finite Element Method (FEM) and Discrete Element Method (DEM). The FEM simulation adopted a porous viscoplasticity model, which considers the compaction in the view of its air void reduction resulted from the squeezing of aggregates and mastics. The DEM simulations provide a view of considering the compaction a process in which aggregate particles translate and rotate to positions forming denser packing. By this approach, particle shape and binder stiffness factors can be considered. The simulation results indicate that both approaches can describe the compaction phenomena consistently with field observations and empirical experience.