Experimental study on bond behaviour between UHM CFRP laminate and steel

Diagonal tension cracks in reinforced concrete members adversely affect the performance of flexural members strengthened by externally boned fiber-reinforced polymer (FRP) materials. The interface between the CFRP plate and concrete is influenced by both shear bond and peeling for such conditions. The objective of this study is to understand bond behavior in CFRP plate and concrete systems under the combination of fracture mode (peeling and shear) by special double-face shear bond test specimen. The specimens were designed for different initial angles at the middle of the specimen to ensure that the interface acts for both shear and peeling conditions. From the test results, the bond behavior under the combination of fracture mode can be observed using special specimens. It is confirmed that the tensile load decreases as the peeling angle increases. The relationship between peeling angle and tensile load is determined to evaluate the bond strength under the combination of fracture mode. Based on the test results, a new calculation method under the combination of fracture mode is proposed. The proposed method makes good prediction of the bond strength between CFRP plate and concrete for shear-peeling fracture conditions.