Experiment on bond performance between CFRP bar and seawater sea sand concrete and its working mechanism

In order to study the bond performance between carbon fibre reinforced polymer (CFRP) bars and seawater sea sand concrete, the pull-out test of CFRP and seawater sea sand concrete was carried out in different conditions and the bond-slip curve was obtained. During the test, different failure modes were observed and concluded to analyze the failure mechanism between CFRP bars and seawater sea sand concrete. The influence of different factors on the bond performance was analyzed based on orthogonal experiment. The results show that the strength of concrete is the most important factor affecting the bond strength, and the friction plays a large part in the bond stress. Besides the pull-out damage and concrete splitting damage, CFRP damage exists in the test due to the production process and mechanical performance of CFRP itself. Based on the results above, three types of bond-slip constitutive relation expression of CFRP/seawater sea sand concrete were finally concluded by curve fitting and comparing.