Investigation on Spent Catalyst-based Self-consolidating Concrete (SCC) RC Beams with Conventional and GFRP Rebars

This study investigates the development of self-consolidating concrete (SCC) incorporating an optimised mix of 9% spent catalyst (SC) and 3% superplasticiser (SP), along with the flexural performance of reinforced concrete (RC) beams using either conventional steel or glass fibre-reinforced polymer (GFRP) rebars. The research focused on evaluating both the mechanical behaviour and environmental benefits of SCC beams with different reinforcement types. Beams were cast with dimensions of 1500 mm in length, 125 mm in width, and 200 mm in depth, with GFRP designs conforming to ACI 440.1R-15 specifications. A total of four specimens were tested under two-point monotonic loading. GFRP-reinforced beams exhibited initial cracking 21.4% earlier than their steel-reinforced counterparts, which is attributed to their higher thermal expansion. However, they achieved a 5% higher peak load due to superior tensile strength and bonding efficiency. In terms of deflection, GFRP beams showed 77% greater deformation, reflecting their lower stiffness, while steel-reinforced beams were 63% stiffer. Although the GFRP beams demonstrated 18.75% lower ductility, their overall performance remained within acceptable limits.