Shear-Bond Behavior of the Interface between FRP Profiles and Concrete by the Double-Lap Push Shear Method

This paper focuses on the bonding performance of the interface between fiber-reinforced polymer (FRP) profiles and concrete. The bond shear capacity and the bond shear strength of the wet-bond (WB) interface, the shear-key (SK) interface, and the shear-key combined with wet-bond (SK-WB) interface were investigated via double-lap push shear tests with 15 specimens. Varying numbers of shear keys were adopted in the SK and SK-WB specimens to study the influence of the bonding area of the shear keys. The slip between the FRP profiles and the concrete was measured, and the bond stresses at different points of the test zone were calculated with differential operations. The results show that the average bond strength and the maximum slip of the SK-WB interface are significantly higher than those of the SK interface, whereas the average bond strength and maximum slip of the SK interface are significantly higher than those of the WB interface. A much greater concentration of stress was discovered in the SK interface compared with the SK-WB interface. The capacity load value and the maximum slip value of the double-SK interface are higher than those same values of the single-SK interface. The comparison of bond strength was performed between the FRP profiles-concrete interface and the FRP plate-concrete interface. The results show that the bond strength of the WB interface between the concrete and the FRP profile by the double-lap push shear method is much lower than the bond strength of the WB interface between the concrete and the FRP plate when using the double-lap pull shear method. Finally, the significant difference in the bond strengths is explained using the stress analysis method. (C) 2017 American Society of Civil Engineers.