Mesoscopic mechanical analysis of the effect of crumb rubber content on rubberized epoxy asphalt mixture under indirect tensile discrete element method simulation

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Behaviors of aggregate skeletons are of critical importance on the performance of asphalt mixture. This study utilizes discrete element modeling (DEM) to assess the influence of crumb rubber (CR) content on the mesoscopic mechanical properties of aggregate skeletons in rubberized epoxy asphalt mixtures. Four virtual specimens with varying CR content were subjected to DEM-based indirect tensile tests to evaluate force chain patterns, contact force properties, and fabric anisotropy. DEM simulations revealed that vertical force chains are primarily pressure-driven, contrasting with the tensile forces in the horizontal direction, which induce central cracking. The presence of CR particles mitigates contact forces between aggregates, impacting the variability of contact forces within the skeleton structure. Notably, a 4% CR content significantly alters these contact characteristics. Additionally, CR particles were observed to regulate the spatial distribution and fabric anisotropy of contact properties, promoting a more uniform contact distribution across the rigid-flexible hybrid skeleton structure with increased CR content. After loading, the principal axis direction of strong contacts aligns near 90°. In conclusion, this research delineates the pivotal role of rubber particles in modulating the mesoscopic mechanical contact properties of epoxy asphalt mixtures, presenting a novel framework for optimizing CR content to enhance the mechanical performance of asphalt mixtures.