Numerical Analysis on the Splitting Test of Open-Graded Large Stone Asphalt Mixture Based on Discrete Element Method

Abstract

The deficiencies of analyzing and calculating asphalt mixture as a perfectly elastic body in the existing structural design theory of asphalt pavement were amended by numerically simulating the splitting (indirect tensile) test of AC - 16, AC - 20, and OLSM - 25 (open-graded large stone asphalt mixture) from the microscopic view based on the discrete element method and 2D particle flow code. The aggregate particle contact forces, displacement vectors, numbers of micro-cracks as well as the distribution laws of the cylindrical specimens of AC - 16, AC - 20, and OLSM - 25 were also analyzed and compared by numerically simulating the splitting test. Results indicated that under the influence of peak axial force, the distribution form of the contact force between the aggregate particles in the specimens changed from being basically uniform into being relatively discrete. When the cylindrical specimen of asphalt mixture cracked, the displacement vector greatly varied from one another with the increase of the nominal maximum size and porosity of asphalt mixture as well as with the decrease of asphalt-aggregate ratio of such mixture. Moreover, the number of micro-cracks was determined to gradually reduce. Compared with AC - 16 and AC - 20, the anti-cracking effect of OLSM - 25 in the indirect tensile test was more significant and remarkable.