The Effect of Adhesive Type on the Bond of NSM Tape to Concrete

Synopsis: Near surface mounted (NSM) reinforcement is becoming a viable material for strengthening existing concrete structures in flexure and shear. As this method moves from the laboratory testing phase to implementation in the field, designers will need to be able to predict the capacity of the strengthening scheme. Bond of NSM reinforcement to concrete will likely be a key factor in determining the strengthened capacity. There are a number of parameters that affect bond between steel rebar and concrete, where only two different materials are present. In the case of bond of NSM reinforcement, a third material, adhesive, is present, further complicating the analytical description of bond of NSM reinforcement. This paper presents the results of two types of bond tests that were used to determine the effect of epoxy adhesive material properties on the bond of NSM tape to concrete. From the testing, it was found that even for epoxy adhesives with similar shear strengths, the bond strength and bond failure mechanisms differ significantly.