Purpose The purpose of this study is to investigate the structural performance of reinforced concrete (RC) beams incorporating recycled coarse aggregate (RCA) when subjected to elevated temperatures. While RCA offers sustainability benefits, its fire performance in structural members remains insufficiently understood. This research aims to evaluate the influence of varying RCA replacement levels and high-temperature exposure on the flexural behaviour of RC beams. Design/methodology/approach RC beams were cast using RCA replacement levels ranging from 0% to 100%. The specimens were exposed to controlled elevated temperatures up to 800 °C using a programmable muffle furnace to simulate fire conditions. After thermal exposure, four-point bending tests were conducted to assess flexural behaviour. Key response parameters, including yield load, ultimate load, deflection, stiffness and flexural rigidity, were experimentally measured. Analytical load–deflection models based on moment–curvature relationships were developed and used to characterize post-fire behaviour, and the analytical predictions were validated against experimental results. Findings The results demonstrate that both elevated temperature exposure and increasing RCA content significantly influence the flexural performance of RC beams. Reductions in load-carrying capacity, stiffness and flexural rigidity were observed with increasing temperature and RCA replacement levels, while deflection increased. The analytical models based on moment–curvature relationships showed good agreement with experimental load–deflection responses, confirming their applicability for post-fire assessment of recycled coarse aggregate concrete beams. Originality/value This study provides original experimental and analytical insights into the fire-exposed behavior of RC beams incorporating RCA. The findings contribute to structural fire engineering knowledge and support the development of sustainable and fire-resilient concrete structures using recycled materials.
Tariq et al. (Fri,) studied this question.