Influence of Mesoscopic Structural Characteristics of Asphalt Mixture on Damage Behavior of Asphalt Pavement

Mechanical responses and damage behaviors of asphalt pavement are closely associated with the mesostructure characteristics of the asphalt mixture. The aim of this research was to investigate the effect of the different mesostructure characteristics of asphalt mixtures on pavement damage behavior through a multiscale finite-element (FE) analysis method. A two-dimensional (2D) random aggregate generation algorithm was used to construct the mesostructures of asphalt mixtures with different characteristics, including aggregate distribution uniformity, shape, volume fraction, and size range. Bilinear cohesive elements were used to model damage initiation within asphalt pavement. Also, the nonuniformity coefficient (NUC) was applied to evaluate the uniformity of aggregate distribution within asphalt pavement. The results indicated that the NUC could well characterize the uniformity of coarse aggregate distribution in pavement, and the damage initiation zone became larger as the NUC increased. Compared with regular aggregates, irregular shape aggregates led to more damage initiation in asphalt pavement. For regular shape aggregates, the damage initiation zone became smaller as the aggregate shape approached the circle. In addition, the decrease of aggregate size and volume fraction could increase the possibility of "top-down" cracking of pavement.