FRP repair of concrete structures: performance in cold regions

This paper summarises work conducted at Queen's University on the performance of concrete members strengthened with Fibre-Reinforced Polymer (FRP) sheets when exposed to cold regions conditions. The freeze-thaw resistance of the FRP-concrete bond is studied by considering small-scale beams (100×150×1200 mm) strengthened with different types of FRP. The results show that no significant bond deterioration occurs when the specimens are exposed to up to 300 freeze-thaw cycles. Recent results that consider the combined effects of freeze-thaw and fatigue loading are discussed. The freeze-thaw behaviour of FRP confined concrete cylinders is also presented. The results show no significant deterioration of the FRP wrapped cylinders due to freeze-thaw exposure even when the cylinders are under sustained load. The low temperature behaviour of concrete beams strengthened with prestressed CFRP sheets is also investigated. In particular, the prestress losses due to low temperature and long-term loading are quantified.