DEM analysis of the effect of geocell on splitting tensile behavior of asphalt mixture based on multi-phase model

Abstract

Herein, an investigation was conducted upon the reinforcement of geocell on the splitting tensile process of asphalt mixture using laboratory tests and the discrete element method (DEM). Micromechanical modeling of geocell-reinforced asphalt mixture and virtual splitting tensile test was built using PFC3D based on the vital material features and mechanical properties of different ingredients (e.g., the three-dimensional irregular shapes and elastic properties of coarse aggregates and geocell, the viscoelastic properties of asphalt mastic, and the random distribution of air voids in asphalt mastic). Meanwhile, the parameters of the DE model were determined by splitting tensile test, and the effects of geocell on the splitting tensile process of contact force, displacement and stress were evaluated through the virtual splitting test. The results indicated the efficiency of the built DE model and virtual test in effectively predicting the splitting process of geocell-reinforced asphalt mixture. Besides, geocell acted mainly in the falling stage of the load-displacement curve during the splitting process, where the contact force distribution of each phase component shifted from the lower to the higher range, and the effect between coarse aggregates was the greatest, followed between coarse aggregate and asphalt mastic, with the least within asphalt mastic. Further, the maximum displacement of asphalt mixture in the X and Y directions was reduced by the geocell, significantly constraining the coarse aggregate and mastic in geocell-reinforced layer. In addition, the stress in the splitting center of asphalt mixture was greater than that at the sides, and the stress within the geocell of the reinforced layer was significantly lower compared to the unreinforced layer, especially in the falling stage. Overall, the present results forge a theoretical basis for the tensile performance of geocell-reinforced asphalt mixture from the microscopical perspective.