Bond-slip behaviors between reinforced concrete and coated rebar via a new strain monitoring method and FEA simulation

Abstract

Bond-slip behavior is a complex interaction between steel bar and concrete, which significantly affects the bearing capacity of the reinforced concrete structures. Considering the practical difficulty to accurately measure the strain of coated rebar in structure, a reliable in-situ test method of integrated strain gauges is proposed to measure the strain of coated steel in this study. Using this test method, the bonding properties between steel bar coated with home-made polymer modified cement-based coating and concrete are investigated. The influence of the rebar diameter, the thickness of cover concrete, and the compressive strength of concrete on the bond-slip property are discussed. The results show that the coating does not reduce or even improve the bonding strength of the coated steel bar and concrete. By increasing the concrete compressive strength or increasing the thickness of cover concrete, the bonding strength of the coated steel bar and concrete is improved. The bonding strength between coated rebar and concrete decreases with the increase of rebar diameter. The numerical model of the coated steel bar and the concrete beam is established by ANSYS software. The bond-slip curves of coated steel bar and concrete obtained by simulation can well describe the curves measured by the experiment. This study lays a foundation for future research on simulating the reinforced concrete beam with coated rebar under accidental load.