3D Discrete Element Modeling of Aggregate Homogeneity Influence on Bituminous Mix Shear Strength

Homogeneity is one of the principal factors affecting the performance-related properties of bituminous mixes, and affects many performance-related properties of bituminous concrete pavements, for example strength, modulus, and service life. This study aims to investigate the influence of aggregate homogeneity on the bituminous mix shear strength using a 3D discrete element method (DEM). The aggregate homogeneity index that is used to assess the aggregate homogeneity in bituminous mixes, and the uniaxial penetration test that is a test method for bituminous mix shear strength were briefly introduced. The aggregate homogeneities were evaluated by the index. A micromechanical discrete element model for the prediction of bituminous mix shear strength was established using imaging techniques and particle flow code in three dimensions. The influence of aggregate homogeneity on the penetration strength of bituminous mixes was simulated on basis of this model. The obtained results were verified by performing an actual uniaxial penetration test. Results showed that the influence of aggregate homogeneity on the bituminous mix shear strength could be simulated using a 3D DEM. There was a good correlation between the aggregate homogeneity and variation of the uniaxial penetration strengths. Better aggregate homogeneity meant less variation in the uniaxial penetration strengths of bituminous mixes; and vice versa.