Fiber-reinforced polymer bars under freeze-thaw cycles and different loading rates

The use of fiber-reinforced polymers (FRP) has increased due to their excellent corrosion resistance, high strength-to-weight-ratio, and stiffness-to-weight ratio. However, different coefficients of thermal expansion of the constituent materials result in high residual stresses which can accentuate microcracking and void generation in cold climates. This article presents the effects on durability of carbon and glass FRP reinforcing bars due to combined freeze-thaw cycles and different loading rates. Specifically, the degradation of FRP bars due to coupled freeze-thaw cycling, tension, and tensile fatigue loading are experimentally investigated. After a series of cyclic environmental preconditioning, the properties of GFRP bars are evaluated from several aspects: ultimate strength under different loading rates, elastic modulus, fatigue strength, and failure mode analysis.