Study On Interfacial Bonding Performance Of CFRP-Steel Plate Under Temperature

Carbon fiber reinforced polymer(CFRP)has been widely used in various of civil engineering reinforcement and repair because of its high strength,corrosion resistance,small thermal expansion coefficient,easy construction,small influence on the appearance of the structure,and wide application range.CFRP sheet coordinates with reinforcement structure by means of the structural adhesive,but the adhesive is thermosensitive,and the current study of performance of CFRP-steel plate interface under the action of temperature is not enough.Therefore,funded by the National Natural Science Foundation of China(Grant No.51578428),the interfacial bonding properties of CFRP-steel plates under temperature was carried out in this paper.Consider the test temperature was 10 ?,30 ?,50 ?,70 ? and 90 ?,CFRP-CFRP lap specimen,steel-steel lap specimen and CFRP-steel double-shear specimen were made in average of 30 pieces,all 120 pieces of specimen,the tensile mechanical properties of CFRP plates,the mechanical properties of structural adhesives and the interfacial bonding properties of CFRP-steel plates under temperature were studied,the main conclusions are as follows:(1)With the increase of the temperature,the elastic modulus of the CFRP plate is almost constant,but the tensile strength and elongation have a certain degree of reduction;the discrete of the elastic modulus,the tensile strength and elongation were all be larger;(2)With the increase of the temperature,the tensile strength of adhesive,the interfacial bonding strength of CFRP-CFRP lap specimen and steel-steel lap specimen are all the first to rise and then continued to decline,and decreased largely after the glass transition temperature;the elongation of the adhesive is gradually increased;the interfacial bonding strength of CFRP-CFRP lap specimen is always bigger than thesteel-steel;(3)With the increase of the temperature,the destroy characteristics of CFRP-steel double shear specimen are changed;the ultimate load and interface bond stiffness of double shear specimen are all the first to rise and then continued to decline,and decreased largely after the glass transition temperature;the strain transfer law of CFRP plate is changed;(4)On the basis of FRP and concrete bond interface research results,the bond-slip relationship model of CFRP-steel bonded interface under temperature is deduced.According to the model,the fracture energy of CFRP-steel plate under different temperature is deduced,and the relationship between the interface fracture energy and the temperature is obtained by fitting,then compared with the test values,the results show that the anastomosis is better.