Experimental Research On The Bond Performance Of CFRP-concrete Interface Under Wet-dry Cycles In Salt Solution

The Carbon Fiber Reinforced Polymer (CFRP) has been widely used for modern engineering structures’repairment and reinforcement due to their excellent mechanical properties and outstanding durability. Bond performance between CFRP and concrete is the key factor of externally bonded CFRP reinforcement structure. However, most current studies devoted to the short-term performance of CFRP-concrete while relatively few researches focus on the long-term performance, relevant research and theories need to be further improved. Environment has a great influence on the durability of structure. CFRP were commonly used in reinforcing coastal and port constructions which are more likely to be corroded due to the sea water and tidal action. This paper designs an experiment to simulated tidal effects on CFRP-concrete interfacial bonding properties. The main contents include:(1)A large number of single shear test specimens were produced to study the interfacial properties of CFRP-concrete with the variables of strength of concrete, bond length of CFRP, bond width of CFRP and the number of cycles of wet-dry in salt solution.(2)Experimental phenomena and failure mode of CFRP-concrete interfaces under wet-dry cycles in salt solution were studied. The debonding process of CFRP-concrete interfaces was described. The interfacial debonding mechanism was analyzed and main results of the experiment were listed.(3)The durability of CFRP-concrete interface under wet-dry cycles in salt solution was studied. Interfacial bond strength were analyzed to study the average bond strength, interfacial fracture energy and interfacial load-slip curve trends effects by the number of wet-dry cycles. Interface shear stress strain distribution and development law were elaborated at last.(4)Existing models for bond behavior were analyzed, by comparing the different models and test results, effective model to describe CFRP-concrete interfacial debonding performance was obtained.(5)The CFRP-concrete interfacial bond-slip relationship was studied. Test results were compared with four simplified models summed up from existing models for CFRP-concrete interfacial bond-slip relationship. Predictable constitutive model of interfacial bond-slip relationship was explored.