Integrating a mortar model into discrete element simulation for enhanced understanding of asphalt mixture cracking

Cracks impact the performance and durability of asphalt pavements, necessitating a comprehensive understanding of the mixture cracking behavior. While discrete element modeling has been implemented, many studies oversimplify the simulation of asphalt mortar, a critical component affecting mixture cracking resistance. This study proposes a mortar model that is applicable to both two‐dimensional (2D) and, to a preliminary extent, three‐dimensional (3D) simulations. The model incorporates a geometric representation of mortar distribution and a mechanical softening model to simulate damage accumulation and fracture. Laboratory and virtual Superpave indirect tensile tests were performed on asphalt mixtures with varying gradations at different aging levels. The virtual simulations successfully mirrored indoor test results in volumetric parameters, load–displacement behavior, and stress distribution. Minor differences in strength, strain, and fracture energy between virtual and indoor tests confirmed the accuracy of the mortar model. Notably, the 3D simulations provided a more accurate reconstruction of the cracking process, showing smaller discrepancies between virtual and indoor results, compared to the 2D simulations, with errors in stress, strain, and fracture energy of 5.6%, 5.7%, and 4.7%, respectively. Employing the mortar model in discrete element simulation revealed insights into fracture angle distribution and tendencies, enabling meticulous analysis of mixture damage characteristics and cracking behavior. This allows for the improved design of mixtures with excellent cracking performance and contributes to advancing computational methods that could complement laboratory testing.