Distribution and Quantification of Force Chains in Asphalt Mixture Using the Discrete Element Method

摘要

Asphalt mixture is comprised of different graded aggregates, asphalt binder and a certain amount of air voids, which is of high heterogeneity. The microscopic responses of contact force are produced in the components and among the components of asphalt mixture under loading, and the contact force network that is the transfer path of loading, namely contact force chains, is formed inside the asphalt mixture. To analyze the distribution and magnitude of contact force chain from the microscopic viewpoint, the 2D microstructure model of asphalt mixture was reconstructed using the discrete element method combined with the digital image processing techniques. The microscopic parameters were assigned to aggregates, sand mastic and interface among aggregates and sand mastic of the discrete element model based on the laboratory test results of aggregates and sand mastic. Then the model is applied to semi-sinusoidal loading, the distribution of contact force chains was obtained, and the quantitative results of the maximum contact force were given in the aggregates, sand mastic and at the interface between aggregates and sand mastic by tracking the contact force at different loading time. The results provide a theoretical basis for analyzing the road performance and damage of asphalt concrete pavement from the microscopic viewpoint.