Effect of rebar embedment length on the bond behavior of commercially produced recycled concrete using beam-end specimens

Abstract In a reinforced concrete element, the bonding of steel rebar in concrete is an important parameter as it affects its structural behavior. While using recycled aggregate to produce structural concrete, the attached mortar in the aggregate may affect the bond with deformed rebar. This study aims to investigate the bond behavior of deformed rebar in 100% recycled structural concrete produced from quality recycled coarse and fine aggregates while varying the embedment length from 200 mm to 300 mm. In this experiment, 20 beam-end specimens were tested to determine the bond efficiency of commercially produced recycled structural concrete and the results were compared with major design and descriptive equations found in ACI 408R03. It can be concluded that the average bond strength was conservative when compared with the design and descriptive equations. Moreover, three simplified descriptive bond strength equations using the ½, ¼, and ¾ root function formula of the compressive strength were proposed to complement the designing and detailing of reinforced recycled concrete structures.