Comparative mechanical performance evaluation of recycled brick aggregate concrete and natural aggregate concrete

Abstract

The global increase in construction and demolition (C&D) waste due to natural disasters and urban redevelopment presents a significant environmental challenge. This study evaluates the mechanical performance of reinforced concrete (RC) beams incorporating recycled brick aggregates (RBA) as a sustainable alternative to natural aggregates (NA). Four concrete mixes were tested: 100 % NA, 100 % RBA, and two hybrid combinations of fine and coarse aggregates. RC beams were subjected to four-point bending tests, and companion cylindrical and prismatic specimens were tested for compressive strength and modulus of rupture (MOR). Results indicate that RC beams made with RBA can achieve shear capacities comparable to those made with NA. While beams incorporating coarse brick aggregates showed a more pronounced reduction in shear strength, with values dropping to 53.0 kN, the highest shear strength (71 kN) was observed in mixes using brick fine aggregates and natural coarse aggregates, nearly matching the 70.8 kN of the 100 % NA mix. However, 100 % RBA mixes exhibited a 24 % reduction in compressive strength and a 16 % reduction in MOR compared to NA mixes. Despite these reductions, the structural behavior and failure modes remained consistent across all compositions. From a sustainability perspective, the use of RBA offers a dual benefit: reducing the demand for virgin aggregates and diverting substantial volumes of brick waste from landfills. In regions where C&D waste constitutes a significant portion of total solid waste, adopting RBA concrete could conserve millions of tons of natural resources annually. This study demonstrates the feasibility of using 100 % recycled brick aggregates in structural concrete, supporting a circular economy approach in the construction sector.