Experimental and analytical study on the effect of different repairing and strengthening strategies on flexural performance of corroded RC beams

This paper reports the results of a study conducted to investigate the flexural behavior of corroded reinforced concrete (RC) beams that were first repaired with different types of cover repairing materials and then strengthened with the carbon fiber-reinforced polymer (CFRP) laminates. Thirteen RC beam specimens were prepared. One specimen was used as a control beam (un-corroded, unrepaired, unstrengthened), and the reinforcing bars in twelve specimens were corroded using an accelerated corrosion setup. While five corroded specimens (two unrepaired and three repaired) were tested without strengthening using CFRP laminates, the other seven corroded specimens (two unrepaired and five repaired) were strengthened with one and two layers of CFRP laminates before testing under flexure. For the RC beams subjected to 10 and 20% corrosion of steel bars (by mass), strengthening using one layer of CFRP laminate enhanced the load-bearing capacities by 89 and 73%, respectively, while strengthening with two CFRP layers improved the load-carrying capacity by 162 and 154%, respectively. Repairing the damaged cover of the corroded RC beams using ultra-high-performance concrete (UHPC) was found to be most effective in enhancing the load-bearing capacity and stiffness, whether the corroded beams were strengthened with CFRP laminates or not. Repairing of the cover using commercial repair material also enhanced the load-carrying capacity and stiffness, with ductility more than that of UHPC. Strengthening of the corroded beams further improved the load-carrying capacity. An analytical model was developed that can predict the load-bearing capacity of the beams with a fair degree of accuracy.