In this paper, the viscoelastic behavior of asphalt mixture was investigated by implementing discrete element method. Two DEM models developed in previous study were adopted directly in this research, which were created based on two types of stone matrix asphalt (SMA) mixture with different aggregate gradations prepared in the laboratory. The increase in applied strain seems to slightly affect both modulus and phase angle. This might be related with both the simplicity of the adopted Burger’s model and the viscoelastic properties of the asphalt mixture which is affected by the increased loading rate. In addition, it was found that the amplified loading strain level obviously induces an increment in the corresponding amount of dissipated energy (DE). It was also confirmed that the developed model is capable of capturing the increasing trend of DE with the increasing frequency. From the study of aggregate shape effect, it was found that under strain-controlled loading condition, aggregate with bigger angularity may cause deduction in the stiffness of the asphalt material. Finally, the tensile forces within mastic were visualized and evaluated and it was discovered that aggregate with larger angularity may cause higher average tensile forces within mastic and consequently increase the risk of crack initiation.

viscoelastic, DEM, asphalt mixture, dissipated energy, aggregate gradation, aggregate shape.