Investigation On Fatigue Bond Behaviour Between FRP Bars And Seawater Sea-sand Concrete

Fibre-reinforced polymer(FRP)bar-reinforced seawater sea-sand concrete(SCCC)structures have a long-term development significance.However,the systematical study on the fatigue bond behaviour between FRP bars and SSSC is limited in the existing research.The systematic research on this aspect can accelerate the application and development of FRP barreinforced SCCC structures.Therefore,in order to comprehensively and systematically grasping the fatigue bond mechanism between FRP bars and SCCC,the experimental study on bond fatigue of basalt fiber reinforced plastic bar(BFRP bar)and SCCC and the bond fatigue tests of glass fiber reinforced plastic bar(GFRP bar)and SCCC were carried out in this thesis.The effect of BFRP bars’ surface shapes,FRP bars diameter,concrete strength and stress level on bond fatigue performance was studied by fatigue bond test.According to the experimental results,some conclusions are obtained.The change of BFRP bars’ surface shapes,FRP bars’ diameter and stress level may lead to the change of bond fatigue failure mode;the bond fatigue failure mode has a great influence on the fatigue bond stiffness curve,the slip curve corresponding to the upper fatigue limit and the residual slip curve;a model which can simulate the fatigue bond stiffness three-stage curve accurately was proposed;the prediction formula of slip corresponding to the fatigue upper limit was proposed,and the bond fatigue failure criterion between FRP bars and SCCC was defined;at the same time,the prediction method of bond fatigue life based on slip corresponding to the fatigue upper limit was proposed;the bond fatigue damage was characterized by residual slip,and a fatigue damage model based on residual slip was established;finally,the fatigue bonding mechanism between FRP bars and SCCC was discussed.