Shear Behaviour of RC Deep Beams Made with Recycled Bricks: Comparative Study

Abstract This study presents a comprehensive examination of the shear behavior in reinforced concrete deep beams, with a particular focus on the incorporation of recycled bricks (RB) as a partial replacement for conventional coarse aggregates. The research explores both experimental and numerical approaches to assess how various factors influence the failure characteristics of these beams. A total of nine beams were tested experimentally to evaluate the effects of different variables, including the proportion of recycled brick aggregate, the grading size of the material, and the shear span-to-depth ratio (a/d). Simultaneously, a numerical analysis was performed using ANSYS APDL to model ten deep beams, concentrating on the layers of recycled brick and varying a/d ratios. Reducing cracking and ultimate load capabilities were the outcomes of raising the recycled brick replacement to 5% and 10%, according to the research. The cracking load, for instance, dropped 10.4% at 5% RB and 29.9% at 10% RB. Beam shear strength also decreased with increasing replacement ratio. Notably, beams with a finer grading size of recycled bricks experienced significant reductions in cracking load 18.5% for 5% RB and 38.5% for 10% RB. The ultimate load capacities of these beams also dropped by 10.4% and 28.9%, respectively. From the numerical simulations, it was observed that the addition of transverse reinforcement enhanced the shear strength of the deep beams. When compared to ordinary concrete deep beams, the installation of steel reinforcement in places crucial to shear performance significantly improved ultimate shear strength by 39.6%, 27.46%, and 21.2%, respectively. Alternatively, compared to beams made completely of regular concrete, the ultimate shear strength was lower when recycled bricks were included into the hybrid cross-sectional regions. The relationship between reinforcement and material composition was presented, which impacts deep beams’ shear capability. It noted beams that were loaded from two directions showed a drop in ultimate shear strength when the shear span-to-depth ratio (a/d) was reduced.