Effect of Environmental Exposure on the Mechanical and Bonding Properties of Hybrid FRP Reinforcing Bars for Concrete Structures

Hybrid fiber-reinforced polymer (FRP) rebar has emerged as one of the most promising and affordable solutions to the brittle failure problems of ordinary FRP rebar in concrete structures. Hybrid FRP rebar stress-strain curves are linearly elastic, and contain a definite yield point followed by plastic deformation. In this study, the long-term durability performance of hybrid FRP rebar is evaluated. The mechanical properties and durability of one type of carbon FRP rebar, one type of glass FRP rebar, and two types of hybrid FRP rebars are investigated. The rebar specimens are exposed to twelve different environments, including an alkaline solution, an acid solution, a salt solution, deionized water, and repeated freezing and thawing. Short-beam, tensile, and bond tests are used to analyze the mechanical properties and durability of the rebar. The experimental results confirm the desirable resistance of hybrid FRP rebar to aggressive environments.