SINGLE-SHEAR TEST OF WET-BONDEDGFRP-TO-CONCRETE INTERFACE

An experimental study consisted of 33 single-shear specimens was conducted to investigate the interfacial behavior between glass fiber reinforced polymer (GFRP) plate and cast-in-place concrete placed against this plate-a method known as wet-bonding. The experimental variables included the initial placement times of concrete (0min., 30 min. and 24 hours following resin placement), durations of concrete curing (7, 14 and 28 days)and interface preparations. Two wet-bonded interfaces were considered: one in which the concrete was placed against the resin and a second in which fine aggregate was broadcast onto the resin during its placement and the cast-in-place concrete placed against the resulting aggregate-impregnated rougher surface. It is shown that the wet-bonded interfaces exhibit lower capacity than dry-bonded interfaces although the load to cause initiation of debonding is not significantly different. The time of initial placement time of the concrete onto the wet, set or cured resin significantly influences the ultimate pullout load. When initial placement of concrete follows initial set of the resin, at about 30 minutes, the ultimate pullout load and interfacial fracture energy are greatest.Specimens in which fine aggregate is broadcast onto the resin immediately after its placement exhibit improved interface performance.