Repair and retrofit of corroded RC beams: A performance review of structural distress and strengthening systems

Reinforced concrete (RC) structures face corrosion risk from inevitable factors such as humidity, chlorides, and carbonation, causing costly global consequences. Rehabilitation of RC beams is critical to ensure structural safety and service life, as corrosion severely reduces strength, ductility, and durability. This paper examines the degradation of corroded RC beams and reviews strengthening and repair strategies and guidance from international codes while identifying research gaps and proposing future strategies. It also provides a retrofit decision matrix for different cases of corrosion in RC beams. Steel plating enhances load capacity but remains prone to continued corrosion and over-reinforcement if not optimized. Engineered cementitious composites (ECCs) and high-performance fiber-reinforced concretes (FRCs) serve dual repair and strengthening functions; the type of fiber significantly affects performance—steel fibers improve flexural strength, while glass fibers enhance ductility. Ultra-high-performance concrete (UHPC) provides exceptional durability and capacity gain but may suffer fracture-like failure and reduced ductility, necessitating hybrid reinforcement. Fiber-reinforced cementitious matrices (FRCMs), though offering modest strength gains, can preserve ductility and, when integrated with carbon fabrics, provide both strengthening and cathodic protection potential. Carbon fiber-reinforced polymer (CFRP) systems perform effectively with proper surface preparation, ECC or UHPC cover replacement, and reliable anchorage. The paper synthesizes these systems, highlighting trade-offs and optimal application, and identifying innovative retrofitting materials such as corrosion-resistant iron-based shape memory alloys (Fe-SMAs), UHPC, FRCM, and green FRPs, which show strong potential for corroded beams strengthening but require further validation, optimization, and practical implementation.