Plate-concrete interfacial bond strength of FRP and metallic plated concrete specimens

Abstract

Bonding of steel or fibre reinforced polymer (FRP) plates by adhesive to the surface of concrete structural elements have become increasingly popular for improving their strength and stiffness. However, these plates are susceptible to debonding prematurely before reaching the designed strength. Therefore, a thorough knowledge of bond behaviour of concrete–adhesive–plate interface is a prerequisite to develop guidelines to avoid failure through the different possible modes. The paper presents thirty six (36) test results for single shear tests conducted on concrete prisms bonded with variety of FRP and metallic plates to evaluate the bond strength and the critical bond length required to sustain the maximum stress on bond for a given plate–concrete interface. The elastic modulus and ultimate tensile strength of the plates of different materials vary between 32–300 GPa and 196–2800 MPa respectively. The design guidelines developed in this study are capable of predicting the critical bond length and ultimate bond strength of any type of plate–concrete interface with good accuracy. The predictability of the ultimate bond strength model is validated using numerous test results taken from the published literature.