Source based shear behavior of reinforced recycled aggregate concrete structures: review

Abstract

The construction industry’s drive toward sustainability has accelerated the adoption of recycled concrete aggregate (RCA). This review synthesizes findings from 123 experimental studies to critically evaluate the shear behavior of reinforced recycled aggregate concrete (RRAC) beams. There are considerable discrepancies in reported performance, particularly at higher replacement levels, attributed to variations in RCA sources, processing methods, and structural parameters. To address this, RCA is categorized into four main sources such as laboratory concrete waste, recycling plants, old structures, and demolition debris to establish performance benchmarks. The review highlights that the replacement levels with less detrimental effects on shear performance are generally associated with high quality RCA sources and favorable beam design parameters, while strengthening strategies such as fiber reinforcement and optimized mixing procedures can effectively mitigate strength reductions at higher replacement levels. Current design codes generally provide conservative estimates, particularly at moderate replacement levels, but are not yet calibrated for extensive RCA usage across different sources in RRAC applications. This underscores the need for tailored provisions that explicitly account for RCA source and treatment. By consolidating divergent findings and identifying research gaps, this review provides actionable insights to support the safe and sustainable use of RCA in structural concrete. © The Author(s) 2026.