Experimental Investigation on the Shear Behavior of Patched RC Beams Without Web Reinforcements: Efficacy of Patching Position with Respect to the Shear Span

Abstract

AbstractSpalling on concrete covers is a type of degradation that commonly appeared in reinforced concrete structures. This form of degradation could occur at the web of shear-span due to, for example, corrosion of reinforcements within the shear span. The degradation will eventually affect the shear strength of that particular section, resulting in un-conservative shear capacity. Patch repair may be an option for restoring the strength of the damaged RC beam. The shear behavior of patched RC beams without web reinforcements is investigated in this study, with a particular focus on determining the effectiveness of patching position with respect to the shear span. Unsaturated Polyester Resin (UPR)-mortar was used in this investigation as a patch repair material. UPR-mortar was applied to patch RC beam web damage at 0.25 and 0.5 of the shear span (measured from the loading point). The RC patched beams accompanied by some normal beams were loaded until failure in the laboratory. The results indicate that patched RC beams exhibit a higher shear capacity than the original undamaged RC beam. Furthermore, UPR-mortar is more effective when applied at 0.25 of the shear span rather than 0.5 of the shear span. This is demonstrated by the evidence that after an initial diagonal crack was formed, the RC beam with patching at 0.25 of the shear span still carries a substantial load before the diagonal crack propagates, causing the beam to fail in shear. Whereas in RC beam with patch repair position at 0.5 of the shear span, the RC beam immediately fails in shear once the significant diagonal crack was formed. However, in NC beams the shear failure occurred earlier than in patched RC beams.KeywordsCrackPatch repairRC beamShearUPR-mortar