Experimental Study on Flexural Capacity of RC Beams with Cross-Section Patching Repair and Strengthening by CFRP Sheet

In recent years, deteriorated RC bridges due to chloride-induced corrosion have been generally rehabilitated using Fiber Reinforced Polymers (FRP) sheet. Especially for the bridge, in which the spalling and peeling of covering concrete were occurred, the delaminated covering concrete should be removed and repaired by cross-section patching before bonding FRP sheet. In this paper, the flexural capacity of RC beams with cross-section patching repair and strengthening by CFRP sheet has been studied. The RC beams repaired by four kinds of polymer cement mortar (PCM) and three kinds of polymer cement concrete (PCC) were evaluated for the different rehabilitation. And also the following two points were discussed. In the field, before the cross-section patching repair work, the adhesive was applied at the interface of placing joint (also tensile reinforcement). And the putty was applied before bonding CFRP sheet for enhancing the effect of strengthening. The effects of applying adhesive and applying putty were described in this study. As the results, if the beams were repaired by patch repair material with less 18kN/mm2 of the elastic modulus, the load bearing capability degrades a little compared with the beam without repair. But when CFRP sheet was bonded to, the effect of strengthening degrades greatly compared with the beam without repair. For applying putty, the increase of the effect of strengthening enhanced a little. And for adhesive coating, the initial bond strength between the rebar and PCM increased, but the bond strength decreased after the slip of rebar.