Research On Bonding Properties Of CFRP And Concrete Under High And Low Temperature Cycle

The externally bonded carbon fiber reinforced polymer(EB-FRP)structure is prone to premature peeling of carbon fiber reinforced polymer(CFRP)and concrete under load,resulting in insufficient performance of CFRP.However,hybrid bonding carbon fiber reinforced polymer(HB-FRP)and externally bonded reinforcement on grooves(EBG)can improve the bond performance of CFRP and concrete.At present,there are many literatures on the bonding properties of FRP and concrete at room temperature,but the effect of temperature cycling on concrete reinforcement structure is less.The EB,HB,and EBG reinforced concrete test blocks are placed in a temperature cycle box with a temperature change of-20? to 60? and 60% RH to simulate the change of ambient temperature after 50 T,100T,150T(12h is a cycle).After the cycle period,the effects of temperature cycle change and different reinforcement methods(EB,HB,EBG)on the bond performance between CFRP and concrete were studied by single shear test,and HB reinforcement was verified by different anchorage distances(60mm,100mm).The effectiveness of the technology.Through research,we can draw the following conclusions:1.The HBI,HBII,and EBG reinforcements at room temperature are about 2.2 times,2.3 times,and 2.3 times stronger than the EB reinforcement.The HB and EBG reinforcement techniques significantly improve the bond strength of FRP-reinforced concrete,and the reinforcement effect is close;2.When HBI and HBII do not undergo temperature cycling,the reinforcement effect is equivalent;but under the action of temperature cycle 50 T,100T,150 T,the ultimate bond bearing capacity is increased by about 1.2 times than HBI reinforcement,HBII is better than HBI reinforcement method,There is an optimal anchoring distance;3.After the EBG reinforcement has been cycled for different cycles,the ultimate bond load decreases significantly.After 150 T,the ultimate bond load decreases by 50.30%.After the different cycles of HBI reinforcement,the ultimate bond load decreases first and then increases;EB,HBII reinforcement has no significant change in its ultimate bond load after different cycles;4.The strain from the distance close to the loading of CFRP in EB,HB and EBG reinforcement becomes smaller with the increase of cycle.