A comparative study of the bond strength of reinforcing steel in high-volume fly ash concrete and conventional concrete

Abstract The production of Portland cement – the key ingredient in concrete – generates a significant amount of carbon dioxide. However, due to its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. An experimental investigation was conducted to compare the bond strength of reinforcing steel in high-volume fly ash concrete (HVFAC) – concrete with at least 50% of the cement replaced with fly ash – with conventional concrete (CC). This experimental program consisted of 12 pull-out specimens as well as 12 full-scale beams (three unconfined and three confined by transverse reinforcement for each concrete type). The pull-out specimens were based on RILEM recommendations, and the beam specimens were tested under a simply supported four-point loading condition. The CC test results served as a control and were used to evaluate the results from the HVFAC pull-out and beam specimen tests. Furthermore, a comparison was performed between results of this study and a bond database of CC specimens. These comparisons indicate that HVFAC beams possess comparable bond strength as CC beams.