Experimental study of the bond strength between steel substrate and CFRP under impact tensile loads

Abstract

Carbon fibre reinforced polymer (CFRP) has attracted a great deal of attention for upgrading and/or rehabilitating steel structures following its successful application for the strengthening of concrete structures. It is vital to maintain a sound bond between the CFRP and the steel substrate during service by selecting appropriate adhesives. The effect of dynamic loading (e.g. impact) on such bond is not well understood. This paper describes an experimental investigation of the efficiency of the bond between steel and normal modulus CFRP sheets under dynamic tensile loads of various loading speeds. The pull-off adhesion testing method was adopted. It was found that significant enhancement in adhesion bond strength for two types of resins was achieved at high strain rates. The failure mechanisms of both adhesives were remarkably influenced by speeds of loading and they illustrated noticeable changes compared to static loads