Virtual design of asphalt mixtures using a growth and contact model based on realistic aggregates

The geometric and distributional characteristic of aggregate contacts in an asphalt mixture significantly affect its load-bearing capacity. An approach to the virtual construction of cylindrical samples with customized aggregate contacts is presented to simulate the internal structure of an asphalt mixture. To obtain virtual samples, coarse aggregates are prepared from a digital library of realistic aggregates, allocated coordination numbers, and placed in a cylindrical container with the expected relations constructed. Next, the air voids and the asphalt mortar are generated in sequence to obtain the microstructure of a virtual specimen. Three AC-13 samples were constructed using different parameters. The difference between actual and expected average coordination numbers is around 6% for AC-13 Marshall samples virtually constructed with appropriate parameters, showing the reliability of the control effect of the proposed approach on the aggregate contact in asphalt mixtures. Furthermore, compared with a realistic AC-13 sample, virtual samples constructed have a close quantity, area, and orientation of aggregate contacts. Moreover, simulation results of the displacement-controlled test indicate the virtual sample with most aggregate contacts has the largest strain energy, demonstrating the correlation between contact properties and deformation resistance.