Bond performance of Steel-CFRP bar reinforced coral concrete beams

Steel-Carbon Fiber Reinforced Polymer (SCFRP) bar provides a new way to solve the shortcomings of poor ductility and low stiffness of FRP reinforced concrete members. In order to understand the bond performance between SCFRP bars and coral concrete, 39 pull-out tests of SCFRP reinforced coral concrete is performed. Different parameters such as the types, diameters and bond lengths of SCFRP reinforcements were investigated. The failure modes, failure mechanism, stress process and bond-slip relationship of the specimens were analyzed. The failure modes of steel bar pull-out can be divided into steel core pull-out before yielding and steel core pull-out after yielding. The concrete splitting failure modes can be divided into coral concrete splitting before steel core yielding and Coral concrete splits after steel core yielding. There are four characteristic points in the bond slip curve: elastic slip point, yield slip point, peak slip point and residual slip point. The bond slip model of SCFRP reinforced coral concrete was developed in this paper using coefficients of slip before steel core yields and slip after steel core yields are 0.86 and 1.0 respectively, which can describe the bond slip behavior between SCFRP and concrete more accurately. (C) 2020 Elsevier Ltd. All rights reserved.