Effect of Short-Term Freeze-Thaw Cyclingon Composite Confined Concrete

Concrete cylinders jacketed with glass and carbon-fiber-reinforced polymer (FRP) composites were exposed to 201 freeze-thaw cycles, and results of compression response were compared with results from similar specimens kept at 22.5°C. Beyond the effect on the concrete itself, freeze-thaw exposure has a significant effect on the composite in terms of both performance and failure modes. Wrapped specimens tested after exposure to freeze-thaw cycling show changes in strength and stiffness and more catastrophic failure modes than similar specimens kept at 22.5°C. Effects of the exposure on the FRP composite and its constituents, as well as interaction effects resulting from FRP composite-concrete bond are elucidated and failure mechanisms are detailed. It is shown that the damage mechanisms seen are those that would increase absorption of water in cases where aqueous solutions may be present. Implications on overall use are discussed.