Micro-structural analysis on stress displacement and crack evolution of porous asphalt mixture based on DEM

Abstract

The purpose of this study is to explore the micro-structure evolution and failure mechanism of porous asphalt mixture under stress. The micro-structural parameters of specimen section are imported into PFC2D, and the change of aggregate displacement is verified by discrete element modeling. Through digital image processing technology, a series of quantitative information of micro structure of mixture section is obtained, and these micro parameters are statistically analyzed, and the statistical results are compared with the macro test. Under the action of stress, porous asphalt mixture produces different degrees of strain. By comparing the meso structural parameters under different strains, the displacement of aggregate and the change process of voids are determined. The results show that with the increase of stress and strain, the specimen is gradually compacted, the aggregate displaces in different degrees, the cracks are gradually generated at the junction of aggregate and cracks, and the specimen is gradually destroyed. The change of void area, void number and void length width ratio can directly show the development process of fracture.