Application of discrete element method to Superpave gyratory compaction

Superpave mix design method is one of the major asphalt mixture design methods and has been widely used worldwide. However, the Superpave laboratory mix design process is time-consuming and requires significant human and material resources. In this study, the discrete element method (DEM) was used to simulate the compaction of hot-mix asphalt (HMA) with the Superpave gyratory compactor (SGC). The open source DEM code, YADE, was modified and implemented with C++programming language to conduct virtual SGC compaction. The effects of aggregate gradation, gyration number, gyration angle, and parameters of contact model during the SGC compaction were investigated. Also, the clump technique was utilised to study the effect of aggregate shape. To verify the DEM simulation results, a laboratory SGC compaction was conducted. The results from the DEM virtual compaction were generally in agreement with the experimental data, indicating that DEM provides a feasible way to simulate asphalt mixture compaction. With further research, DEM has the potential to be a helpful tool for aggregate selection in asphalt mix design.