Shear Strengthening of Corroded RC Beams Using UHPC-FRP Composites

摘要

In this paper, ultrahigh-performance concrete (UHPC) combined with fiber-reinforced polymer (FRP) composites is proposed for the shear strengthening of corroded reinforced concrete (RC) beams. The UHPC-FRP composites are utilized to replace the spalled concrete cover in corroded RC beams. UHPC helps controlling the crack width and preventing the corrosive substances in the environment from invading the internal steel stirrups, whereas the carbon FRP (CFRP) meshes are embedded in UHPC to increase its tensile strength. The experimental study shows that the UHPC---FRP shear strengthening significantly increased the shear capacity of the RC beams and suppressed the formation of shear cracks. The introduction of thin CFRP meshes in UHPC greatly decreased the crack width in concrete. No debonding was observed between FRP and UHPC. The shear capacity contribution between the steel stirrups and UHPC-FRP composites was affected by the corrosion level in the existing internal shear stirrups. An analytical model is proposed for the prediction of shear capacity contributions of all materials to the strengthened RC beams, which shows satisfactory precision as compared to the experimental data.