The effect of particle shape on the meso-structure of mixture skeleton based on DIP and 3D DEM

Mixture skeleton is the main body bearing the load of asphalt mixture, and particle shape is an important factor affecting the meso-structure of mixture skeleton. Based on the minimum bounding box theory, obtain particles geometry by Digital Image Processing (DIP), and calculate the shape indices: angularity index (A1) and flat-elongated index (F1). By using discrete element method (DEM) software PFC3D, five mixture skeletons were built with different integrated angularity (Am) and flat-elongated particles content (Fm). And analyzed air void, particles distribution and particle angle of mixture skeletons. The results show that Am has no obvious effect on the air void ratio, but increasing Fm can increase the air void ratio. In addition, the index U3D was proposed to evaluate particles distribution on 3D scale, and found that small particles are more likely to have better distri-bution uniformity. And uniformity of particles distribution in mixture skeleton will increase with the increase of Am. For particles, angle will be increase with the increase of F1. However, if F1 is too large, particle angle will decrease due to the embedding effect. These studies and results analyzed that how can particles shape affect meso-structure of mixture skeleton.