Thermo-Mechanical Durability of Carbon Fiber Reinforced Polymer Strengthened Reinforced Concrete Beams

摘要

In recent years the Federal Highway Administration (FHWA) has identified a critical need to upgrade the transportation infrastructure in the United States. Of the nearly 600,000 bridges in the FHWA's bridge inventory, upwards of 90,000 bridges have been deemed structurally deficient and are in need of rehabilitation to increase member capacity. Research has shown that externally-bonded fiber-reinforced polymer (FRP) composite materials can provide an effective means to upgrade deficient structures. Yet, there exists a question as to the long-term durability of this type of retrofit technology. The study presented discusses the results from a large-scale experimental study focused on the effects of mechanical and thermal fatigue on reinforced concrete (RC) beams strengthened with externally-bonded carbon fiber-reinforced polymer (CFRP) sheets. Three different resin matrix systems were investigated: two epoxy systems and one pre-impregnated polyurethane system. Specimens were subjected to 2 million loading cycles and/or one year of thermal/humidity cycling previous to monotonic loading until failure.