Influence of bonding technique on bond behavior of CFRP-to-clay brick masonry joints: Experimental study using particle image velocimetry (PIV)

This paper presents a comparative study on the performance of three different techniques for bonding carbon fiber reinforced polymer (CFRP) sheets to masonry substrate. To do so, eight CFRP-to-clay brick masonry joints were prepared using conventional externally bonded reinforcement (EBR) technique, with and without surface preparation. Moreover, for the first time, grooving method (GM) in the form of externally bonded reinforcement on grooves (EBROG) technique was used for bonding CFRP sheets to masonry substrate in six other joints. The specimens were tested under single lap-shear loading and the influence of bonding technique as well as effect of fiber reinforced polymer (FRP) bond length were comprehensively investigated and discussed based on the experimental results. A non-contact full field deformation measurement technique, i.e. particle image velocimetry (PIV), was used to obtain the load–slip diagrams, strain profiles along the bonded length, and strain fields of all tested specimens. Experimental results and PIV measurements demonstrated that bond behavior of CFRP sheets attached to masonry substrate was significantly improved by using EBROG technique. Consequently, the technique can be used as an alternative to conventional EBR method to more efficiently utilize the tensile capacity of FRPs used for external strengthening of unreinforced masonry (URM) structures.