FRP Repair of Corrosion-Damaged Reinforced Concrete Beams

Corrosion of steel reinforcement is one of the main durability problems facing reinforced concrete infrastructures worldwide. This paper will summarize the results of a multi-phase experimental program undertaken at the University of Waterloo to investigate the viability of using externally bonded fiber reinforced polymer (FRP) laminates to rehabilitate corrosion-damaged reinforced concrete beams. Several reinforced concrete beams with variable chloride levels (0 to 3%) were constructed. The beams were strengthened or repaired by externally epoxy bonding FRP laminates to the concrete surface. The tensile reinforcement of the specimens was subjected to accelerated corrosion by means of impressed current up to 15% mass loss. Strain gauges were used on the FRP laminates to quantify tensile strains induced by the corrosion process. Following the corrosion phase, the specimens were tested in flexure in a four-point bending regime. Test results revealed that FRP laminates successfully confined the corrosion cracking and spalling due to expansion of corrosion products. The FRP strengthened beams exhibited increased stiffness over the unstrengthened specimens, and marked increases in the yield and ultimate strength. The results showed that the use of FRP sheets for strengthening corroded reinforced concrete beams is an efficient technique that can maintain structural integrity and enhance the behavior of such beams.