Shear strength behavior of high-strength fly ash concrete beams with low-bond reinforcement

Abstract

This study aims to investigate the shear behavior of high-strength fly ash (HSFA) concrete beams with low-bond reinforcement (LBR). With this purpose, twenty-three HSFA concrete beam specimens were constructed and tested. The experimental results showed that owing to the high-strength property of LBR, the tested beams easily failed in shear. The shear strength of the HSFA beams was mainly controlled by the shear span to depth ratio (a/d) and transverse reinforcement ratio. The shear strength Vs carried by the transverse reinforcement started to increase when the shear strength Vc carried by the concrete started reducing or growing at a lower rate. Formulas in design provisions, except for strut-and-tie model (STM) and those in the “AIJ standard for structural calculation of reinforced concrete structures” proposed by Architectural Institute of Japan (AIJ), could not accurately assess the shear strength of HSFA concrete beams because they do not reasonably consider the effect of a/d on the Vc. Generally, the current design models underestimate the Vs. Based on the test results, a new model that can reasonably consider the effect of a/d on Vc was proposed to accurately evaluate the shear strength of HSFA concrete beams reinforced by LBRs. This study deepens the understanding of researchers and engineers of the shear behavior of HSFA concrete beams with LBRs.