A study on the discrete element simulation of heterogeneous asphalt under freeze–thaw cycles

To investigate the meso-mechanical behavior of heterogeneous asphalt mixtures more effectively, a discrete element method (DEM) model was developed and used to simulate uniaxial compression tests. The Weibull distribution function was introduced into the model to characterize the heterogeneity of asphalt particle contact strength, and a nonlinear damage equation derived from linear damage theory was utilized to simulate the initial damage evolution process of the asphalt mixture. The results show that: (1) After 5, 10, and 15 freeze–thaw cycles, the peak stress of the asphalt mixture decreased by 12.2%, 18.7%, and 24.9%, respectively, while the peak strain increased by 1.92%, 6.14%, and 16.1%, consistent with experimental results. (2) Both simulation and experimental damage variable evolution diagrams exhibit an ‘S’ shape, and the Weibull function effectively expresses the heterogeneous characteristics of the asphalt mixture. (3) The shape parameter m characterizes the peak stress and brittleness of the material, while the scale parameter a characterizes its deformation capacity.