Strategies for strengthening of corroded reinforced concrete beams using CFRP laminates and UHPC jacketing

This article aims to investigate the flexural behavior of strengthened corroded reinforced concrete (RC) beams using carbon fiber-reinforced polymer (CFRP) laminates and using a hybrid system of CFRP laminates and ultrahigh-performance concrete (UHPC) layers. A total of 15 RC beam specimens were prepared, out of which one specimen was uncorroded–unstrengthened, and 14 specimens were corroded using accelerated corrosion set up to cause a significant reduction in the load-carrying capacity of the RC beams. The damaged covers of the corroded RC beam specimens were first repaired and then strengthened with different strengthening strategies involving CFRP laminates alone as well as the CFRP laminates and UHPC jacketing together. The experimental results obtained by testing the strengthened RC beam specimens in flexure showed a significant enhancement in the load-carrying capacity and stiffness of the strengthened corroded RC beams. The number of CFRP laminates, hybridization of the CFRP laminates and UHPC layer, and the thickness of the UHPC layer all significantly improved the load-carrying capacity and stiffness of the strengthened corroded RC beams indicating the possibility of selecting an optimal strategy out of different options for strengthening the corroded beams to achieve a targeted degree of the efficacy of the strengthening. The analytical model developed in this study to estimate the flexural capacity of the strengthened RC beams was found to predict the values of the load-bearing capacity of the RC beams strengthened using different strategies very close to their respective experimental values.