Effect of bond strength on fiber reinforced polymer enveloped concrete cylinders with rebars exposed to corrosion activity

This paper aims to investigate the effect of bond strength of corroded steel rebar embedded in concrete cylinders enveloped externally using hybrid and non-hybrid fiber reinforced polymer (FRP) reinforcement. A series of 16 concrete cylinders (i.e. 100 mm x 200 mm) embedded with steel rebar were prepared in the laboratory condition. The test variables were types of fiber reinforced polymer wrapping (i.e. hybrid and non-hybrid fiber reinforced polymer reinforcement), duration of corrosion activity, and percentage of mass loss in steel rebar. The specimens were immersed in 5% NaCl solution at a depth of 170 mm and anodic current was impressed through the rebar for accelerating the corrosion activity. After the exposure period of 24 days, the embedded steel rebar in concrete cylinder was pulled out monotonically to failure. The bond strength, percentage of mass loss in embedded steel rebar, and effect of different periods of corrosion activity on concrete cylinders enveloped with hybrid and non-hybrid fiber reinforced polymer reinforcement are addressed. Test results show that the observed bond strength of hybrid fiber reinforced polymer confined specimens was the highest as compared to the non-hybrid CFRP and GFRP confined specimens. Moreover, the bond strength performance of hybrid FRP confined specimens was slightly better than the non-hybrid CFRP confined specimens.