Research on the tensile fracture mechanism of reinforced rubber concrete under impact loading conditions

In order to study the application of steel fiber rubber concrete (SFRuC) in impact resistance and maintenance structures. This study, the effects of two key variables-rubber content (0%, 3%, 6%, 9%, and 12%) and impact velocity (3 m/s, 6 m/s, and 9 m/s)-on the dynamic behavior of SFRuC were systematically investigated. Dynamic splitting tensile tests were conducted using a 50 mm diameter Split Hopkinson Pressure Bar (SHPB) apparatus. The results reveal that increasing rubber content leads to a gradual reduction in peak stress. Notably, specimens with higher rubber content exhibited an extended post-peak plateau, indicating improved energy dissipation. In contrast, increasing impact velocity produced a linear increase in peak stress, suggesting a rate-sensitive response. These findings suggest that rubber content and impact velocity jointly influence the fracture characteristics of SFRuC. An optimal combination of these parameters can significantly enhance the material’s energy absorption capacity. The toughness index, which reflects this energy absorption ability, was found to be strongly dependent on both variables. Furthermore, Scanning electron microscopy (SEM) revealed two primary failure modes: fiber pull-out and fiber fracture. In mixtures with higher rubber content, energy dissipation predominantly occurred through fiber pull-out. When the applied stress exceeded the tensile strength of the fibers, fiber breakage became the dominant mechanism, often accompanied by matrix spalling. Overall, this research supports the viability of utilizing steel fiber-reinforced rubber concrete in impact-resistant and protective structural applications. To gain a comprehensive understanding of its applicable scope within the structural context, further in-depth research is required.