Deterioration Mechanism of EVA-Modified OPC-SAC Pavement Repair Materials under Extremely High Temperatures

Rising infrastructure demands push cement-based repair materials to their limits. Hot-patch scenarios subject OPC-SAC blends to wide temperature swings that disturb hydration, destabilise hydrates, and resulting in micro-cracking, reduced toughness, and increased maintenance demands. We prepared EVA-latex modified OPC-SAC, exposed it to 20–80°C, and tracked property evolution. At 23°C, EVA cut flexural/ compressive strength by 25.9%/31.5%. From 23°C to 80°C, compared to the plain blend, the reduction in flexural strength of the modified composite stabilized at high temperatures (after an initial complex variation), while the compressive strength increased 5.79% higher than the control group, demonstrating EVA’s stabilizing effect under extremely high temperatures.