Effect of groove characteristics on CFRP-to-concrete bond behavior of EBROG joints: Experimental study using particle image velocimetry (PIV)

Externally bonded reinforcement on grooves (EBROG) technique has been recently introduced as a promising alternative to conventional externally bonded reinforcement (EBR) to eliminate debonding of fiber reinforced polymer (FRP) sheets from concrete substrate. FRP-to-concrete bond behavior in EBROG technique, however, has not been comprehensively investigated up to now due to the novelty of the technique. Consequently, the intention of the current study is to experimentally investigate the effect of groove characteristics on CFRP-to-concrete bond behavior of EBROG joints. To do so, a set of single-shear bond tests were conducted on 9 concrete prism specimens and the effects of groove dimensions (i.e. width and depth) on CFRP-to-concrete bond behavior of tested specimens including load bearing, failure mode, load-slip behavior, and strain distribution were discussed. Bond-slip behavior of CFRP sheets in EBROG technique was obtained for the first time, utilizing an accurate image-based deformation measurement technique, i.e. particle image velocimetry (PIV). PIV analyses demonstrated that EBROG technique can significantly improve the interfacial fracture characteristics of CFRP-to-concrete bonded joints.