Homogeneity of Asphalt Mixture at Mesoscopic Level Based on DEM Simulation and Low-Temperature Splitting Test

The homogeneity of asphalt mixture has a significant impact on road performance; however, it has largely been studied at the macro-level, with only a few studies at the meso-level. Hence, in this study, the homogeneity of asphalt mixtures with different meso-levels was studied using the 3D discrete element method. The results showed that: (1) the AC13 gradation specimen exhibited the highest number of contact forces of particles, followed by AC16, and lastly AC20; nevertheless, the homogeneity in their contact force distributions was consistent. (2) In terms of the particle displacement, the side closest to the loaded plate exhibited the largest displacement, whereas the side closest to the unloaded plate exhibited the smallest displacement, and the displacement direction was related to the aggregate distribution characteristics. (3) In terms of particle cracks, the specimen order for the number and homogeneity was AC13 > AC16 > AC20. (4) The number of contact forces and number of cracks both showed a clear relationship with the splitting strength. The coefficient of variation in the contact force number and the coefficient of variation in the splitting strength had no clear relationship. In comparison, the coefficient of variation in the crack number and the coefficient of variation in the splitting strength had a strong relationship.