Three-dimensional simulation of asphalt mixture incorporating aggregate size and morphology distribution based on contact dynamics method

Aggregate size and morphology distribution have crucial influences on the performance of asphalt mixtures. In recent decades, the discrete element method (DEM) has been widely adopted to reconstruct aggregate particles and simulate the performance tests of asphalt mixtures. However, most simulations assume a simplification in the particle shape and neglect irregular particle features and its morphology distribution. In this study, based on the acquisition of three-dimensional (3D) aggregate shapes using laser scanning, the morphological characteristics for a large number of particles were analyzed statistically by image processing technology. Numerical asphalt mixture samples were generated by Voronoi tessellations combining the particle size distribution and morphology statistics. The model reliability has been validated by conducting experiments and simulations based on the Contact Dynamics (CD) method for the complex modulus test. Using this procedure, the aggregate morphology and size distribution could be incorporated in numerical simulations of asphalt mixtures. It also implies a significant computational-time reduction by skipping several preparation stages for polyhedral samples. The simulation method can be used to study granular systems as inclusion in a solid matrix such as asphalt mixtures. Furthermore, the micro-mechanism of mixture damage initiation can be revealed at the particle-scale by using the proposed method.