Flexural performance of reinforced recycled aggregate concrete beams

The amount of concrete waste has increased significantly over the years due to reconstruction and the demolition of old buildings. Efforts have been made to utilise recycled aggregates to address some of the environmental problems associated with concrete waste and to promote the sustainability of concrete. A number of studies have been carried out to examine the mechanical properties, mixture design and structural performance of reinforced concrete (RC) beams comprising recycled aggregate. These studies report a reduction in strength, relatively large deflections and wider crack widths in reinforced recycled aggregate concrete beams compared with conventional concrete members. This study evaluates the flexural performance of RC beams with recycled aggregate and proposes strain limits for tension-controlled behaviour. Eight full-scale RC beams were cast using different types of recycled aggregate, including recycled fine and/or coarse aggregate, and using different grades of recycled aggregate that have different replacement ratios. This study also examines the flexural performance of reinforced recycled aggregate concrete beams in terms of crack patterns, flexural strength, ductility and failure modes. The flexural strength and material properties of the RC specimens with recycled aggregate are compared with the predicted values based on the ACI 318 code.