Effects by property homogeneity of aggregate skeleton on creep performance of asphalt concrete

Since the aggregate skeleton of asphalt concrete is mainly formed by the coarse aggregates and it has important influences on the creep performance of asphalt concretes, this paper evaluated the property homogeneity of coarse aggregate skeleton on the creep performance of different asphalt concretes. Two different asphalt concretes with the same maximum nominal size of 13 mm but different gradation types, which are dense-graded Superpave asphalt concrete (SUP13) and gap-graded stone matrix asphalt concrete (SMA13) were prepared and evaluated. The particle flow code in three dimensions (PFC3D), which is a software based on discrete element method (DEM), was used for the discrete element modeling of asphalt concrete and the numerical simulation of laboratory creep test for asphalt concrete. The property homogeneity variation of aggregate skeleton was considered to follow Weibull distribution during DEM modeling. Based on the numerical analysis for different asphalt concretes, the influences by property homogeneity of aggregate skeleton on the macro creep performance of asphalt concrete and the distribution of micromechanical contacting forces within asphalt concrete were analyzed. It is found that the property homogeneity variation of aggregate skeleton generate obvious impacts on the creep performance of asphalt concrete through affecting the micromechanical contacting forces within asphalt concrete. And the property homogeneity variation of aggregate skeleton causes more obvious influence on the creep performance of asphalt concrete with stronger aggregate skeleton. Thus, improving the property homogeneity of aggregate skeleton is a benefic method to promote the creep performance of asphalt concrete, especially for the gap-graded asphalt concrete.