Mesoscopic damage mechanisms and energy dissipation in rubberized concrete: A discrete element method study

Abstract A mesoscopic numerical model of rubberized concrete (RC) was established using the Discrete Element Method (DEM) to simulate the static uniaxial compression behavior of RC with varying rubber sizes (3, 5, and 7 mm) and volume fractions (0%, 4.46%, 8.92%, and 13.38%). The model incorporated the influences of four types of interfacial transition zones (ITZs): rubber‐mortar, rubber‐aggregate, mortar‐aggregate, and aggregate‐aggregate. The reliability of the model was validated through experimental comparisons. The uniaxial compression simulations revealed that as the rubber content increases, the failure mode RC shifts from a tensile‐shear composite failure to one dominated by shear failure. At higher rubber content (13.38%), the stress fields around rubber particles interact, leading to microcracks preferentially propagating along paths connecting rubber particles. The incorporation of smaller rubber particles introduces more weak interfaces, significantly increasing the number of interfacial microcracks. With increasing rubber content, ITZ failure within the specimen increases and replaces mortar failure as the primary component of specimen damage. The addition of rubber reduces the propagation rate of microcracks within the concrete. In all rubber particle size groups, the stress in aggregates and mortar decreases with higher rubber content, while the contribution of rubber to load‐bearing capacity is nearly negligible. RC exhibits improved energy dissipation capacity and toughness. For instance, in the specimen with 3 mm rubber particles and 13.38% rubber content, the damage threshold and energy dissipation rate at peak stress increased by 45.7% and 77.9%, respectively, compared to ordinary concrete. Additionally, the elastic‐strain energy is stored for a longer duration, resulting in a pronounced “plateau stage” near the peak. The findings elucidate the mesoscopic damage mechanisms and energy evolution behavior of RC, providing a basis for optimizing its performance and promoting engineering applications. The established numerical model also offers a reference for further mesoscopic studies on RC.