The Study On Bond Behavior Between FRP Bar And Concrete In High Temperature

Fiber-reinforced polymer (FRP) composites have been widely used for a variety of civil engineering application. Among their benefits is high tensile strength, light weight, resistance to corrosion, etc. The thermal stability of FRP bar is poor. Similar to RC structure, the adhesive property between FRP and concrete is the foundation of their joint work. The adhesive property changes distinctly when temperature higher than glass transition temperature (Tg) of FRP, which is different from RC structure.The main objective of the research is to analyze and simulate the behavior of FRP-concrete bond. The aspects that were studied in this research are as follows:(1) Analyze and simulate the temperature field of FRP-concrete members by using finite element software MATLAB. The objective of this part is to provide data about heat up time for later sections.(2) GFRP bars and concrete are all in linear elastic stage in the studied temperature ranging from 20 to 190℃. The primary objective of this study is to develop equations of the bond stress and relative slippage between FRP bars and concrete exposed to different temperature, using a bilinear model. Equations were established through theoretical analysis and simulation of the bond-slip constitutive relationship. According to the expressions, the variations of the bond stress and relative slippage between FRP bars and concrete can be evaluated at different locations.(3) To evaluate the theoretical formula of bond stress and slippage deduced in the Chapter three and make further efforts on the behavior of FRP-concrete bond, experimental studies are carried out on concrete prism specimens exposed to high temperature under axial load. The bond strength of GFRP bars are investigated through test. The slippage (both free end fixed end) of FRP-concrete bonding specimen is also measured in the text.