Flexural behavior of optimized crumb rubber multilayer concrete slab

Waste tires are a significant environmental issue, and this study explores the use of crumb rubber concrete (CRC) as a sustainable alternative by incorporating waste rubber from discarded tires as a partial replacement for fine aggregate (sand) in concrete. Seven slab specimens were tested, including a control specimen and six rubberized concrete specimens with 25%, 50%, and 75% rubber content in one-layer and two-layer configurations. The results showed that increasing rubber content led to a decrease in compressive strength and ultimate load capacity, with reductions of up to 85.5% in one-layer slabs and 50% in two-layer slabs compared to the control slab. However, CRC demonstrated a lower density, making it a potential lightweight material. Indirect tensile strength showed mixed results slightly increasing at lower rubber content but decreasing as more sand was replaced. While CRC offers significant environmental benefits, its mechanical performance limitations must be carefully considered for structural applications. Increasing rubber content also reduced workability, requiring adjustments in mix design. Despite these challenges, CRC has the potential to be a sustainable and eco-friendly construction material if optimized for strength and usability. Future research could focus on improving its mechanical properties through admixtures or alternative mix designs to enhance its application in modern construction