Bond Performance of Sustainable Reinforced Concrete Beams: Fid-Bau Portal

Bond Performance of Sustainable Reinforced Concrete Beams

Seyedhamed Sadati

Proper force transfer between reinforcement and surrounding concrete is one of the most significant factors affecting the structural performance of reinforced concrete. Because of the increasing interest in using fly ash and recycled concrete aggregate (RCA) in structural applications, it is necessary to investigate bond properties of mixtures proportioned with high volume of these materials. The present study investigates bond strength between concrete and reinforcing steel in full-scale beams constructed with various "green" concrete mixtures, including high-volume fly ash concrete containing 50% Class C fly ash replacement (FA50), concrete with 50% of coarse RCA replacement (RCA50), as well as a so-called "sustainable concrete" (SC) proportioned with 50% Class C fly ash and 50% RCA. Conventional concrete (CC) made without any fly ash and RCA is employed as the Reference mixture. Data obtained from the testing of 11 full-scale spliced beams are analyzed, including one beam per concrete type (except for RCA50) for investigating the top-bar effect. Experimental results are compared to six different analytical models available in literature. Results are also evaluated based on the bond database of specimens fabricated with RCA developed through literature survey as well as the database proposed by ACI Committee 408for bond in CC. On average, SC specimens exhibited 15% higher normalized bond strength compared to the Reference beams. Performance of SC mixture was similar to that of RCA50, which were both slightly (6%) lower than that of the FA50 beams in terms of bond strength. No sign of top-bar effect was observed for the FA50 and SC beams.