Discrete Element Modeling of Aggregate Gradation Influence on the High Temperature Stability of Structural-Layer Asphalt Mixtures

This paper uses a three-dimensional (3D) discrete element method (DEM) to investigate the influence of aggregate gradation on the high temperature stability of structural-layer asphalt mixtures, evaluated by the uniaxial penetration test and creep test. Particle flow code in three dimensions was used to establish 3D models for the uniaxial penetration test and creep test. These models were used to simulate shear strength and creep behavior of structural-layer asphalt mixtures. Results were verified by performing actual uniaxial penetration tests and creep tests. The results showed that the high temperature stability of structural-layer asphalt mixtures could be simulated well by using the 3D DEM, and aggregate gradation significantly affected the high temperature stability of structural-layer asphalt mixtures. With an increase in coarse aggregate, particularly with a greater diameter, the shear strength increased, and the creep rate decreased, implying that the high temperature stability of structural-layer asphalt mixtures improved.