Effect of Crumb Rubber on the Performance of Fly Ash-Based Glass Fibrous Concrete Exposed to Elevated Temperature

Tire waste, which is driven by industrial growth and global waste accumulation presents a significant environmental challenge. Recycling tire rubber in construction materials offers a practical and sustainable solution that reduces waste and supports Sustainable Development Goals by enhancing the resource efficiency. However, the incorporation of crumb rubber into concrete presents technical difficulties owing to poor bonding with cement, leading to weak adhesion and a porous interface. This weak bond diminishes concrete strength and increases the risk of premature structural failure. Exposure to high temperatures further compromises the mechanical properties of concrete, notably reducing its compressive strength, stiffness, load-bearing capacity, and structural integrity. This study examines the performance of fly ash-based glass fibre-reinforced concrete (GFRP) incorporating crumb rubber as a partial replacement for fine aggregates. In this study, the compressive strength and spalling behaviour of concrete mixtures with 0%, 10%, and 20% crumb rubber replacement were subjected to elevated temperatures of 200 °C, 500 °C, and 800 °C. The results demonstrated that the highest compressive strength of 27.76 MPa was achieved by concrete without crumb rubber. Introducing crumb rubber led to a notable reduction in the compressive strength; however, it improved the concrete resistance to spalling and enhanced its post-fire performance. In particular, concrete with a 10% crumb rubber replacement exhibited a 9.23% mass loss at 800 °C, which was only 4% higher than its mass loss at 500 °C. Despite the reduction in mechanical strength, the inclusion of crumb rubber significantly enhanced the ability of the concrete to withstand high temperatures. This study highlights the dual benefits of crumb rubber in sustainable construction, addressing waste reduction, while improving the thermal resistance and durability of concrete under extreme conditions.