Durability of hybrid FRP reinforcing bars in concrete structures exposed to marine environments

Abstract

To solve the brittle failure of existing FRP rebar, we developed hybrid FRP rebar that has more than 3% strain and plastic deformation like a steel reinforcement. So, the developed hybrid FRP rebar has emerged as one of the most promising and affordable solution to the brittle failure problem of existing FRP rebar in concrete structures. In this study, the durability of hybrid FRP rebar exposed to marine environments was evaluated. The performance degradation of three types of hybrid FRP rebar and one type of GFRP rebar were investigated after exposure to marine environment. Laboratory simulated a marine environment with solutions of NaCl, Na2SO4, and CaCl2, and repeated dry/wet and freeze/thaw cycles after immersion in salt water. Performance assessment was based on tensile strength, short beam tests, and bond tests. All test results showed high residual strength under the all condition. The experimental results confirm the desirable resistance of hybrid FRP rebar to marine environment.