Heterogeneity effect of mechanical property on creep behavior of asphalt mixture based on micromechanical modeling and virtual creep test

Based on laboratory tests and discrete element method (DEM), this study investigated the influences by mechanical property heterogeneity of different ingredients of asphalt mixture on the creep behavior of asphalt mixture. By considering the important material features and mechanical properties of different ingredients, such as the three-dimensional irregular shapes and elastic properties of coarse aggregates, the continuous characteristics and viscoelastic properties of asphalt mastic, and the random distribution and zero mechanical property of air voids within asphalt mastic, micromechanical modeling of asphalt mixture and virtual uniaxial static creep test was built by using PFC3D. Weibull distribution was used to describe the heterogeneity of mechanical property for coarse aggregates and asphalt mastic within asphalt mixture. And the influences of the mechanical property heterogeneity of aggregates and asphalt mastic on the creep behavior of asphalt mixture were evaluated based on virtual creep test. The results show that the built discrete element model and virtual test can well predict the creep behavior of asphalt mixture. Both the heterogeneity of mechanical property of aggregates and mastic have negative influences on the creep behavior of asphalt mixture by affecting the distribution of micromechanical forces within asphalt mixture. And heterogeneity of mechanical property of coarse aggregates causes more obvious influences. It is important to guarantee the homogeneity of mechanical property of coarse aggregates and asphalt mastic within asphalt mixture to resist creep deformation.