Experimental characterization of concrete-epoxy interfaces

This study presents experimental procedures conducted to characterize the bond between concrete and fiber reinforced polymeric laminates. The experimental characterization was aimed at obtaining the softening of the concrete-epoxy interface (CEI) formed during the installation of these laminates. In particular, splitting tensile and three-point bending tests were used to determine the tensile strength (f(1)), the size-effect fracture energy (G(f)), and the cohesive fracture energy (G(F)) Of two concrete-epoxy interfaces. The sensitivity of these properties to the type of epoxy, specimen geometry, and surface conditions was also investigated experimentally. From this study, it was found that the tensile strength (f(t)) and the cohesive fracture energy (G(F)) of plain concrete and the two concrete-epoxy interfaces under consideration are similar in magnitude. Conversely, the size-effect fracture energies (G(f)) of plain concrete and a CEI are up to 64% different. Experimental results indicate that the condition of the concrete surface is the principal factor affecting the size-effect fracture energy (G(f)) of a concrete-epoxy interface. Results also indicate that the size-effect fracture energy (G(f)) can be used to characterize and compare concrete-epoxy interfaces.