Durability of Concrete Beams Externally Reinforced with CFRP Composites Exposed to Various Environments

Abstract

In this paper, the effects of various environmental exposure conditions on concrete beams externally reinforced with carbon-fiber-reinforced polymer (CFRP) composites were studied. To evaluate the overall environmental effects on the durability of the interfacial bonding between concrete and CFRP, different commercial composite systems were investigated under various exposure conditions by using a new test method suggested previously. Results showed that the flexural strength of the beam specimens was reduced with environmental exposure. The commercial systems showed significant differences in the relative strength loss, although they were all intended for the same application, suggesting that durability is highly dependent on the epoxy system used in the composite. Under exposure to water and other fluids with different temperatures, CFRP systems employing wet lay-up composites showed high durability with the exception that one system revealed a considerable loss in strength with elevated temperature and time. A system using a precured laminate exhibited a large reduction in strength with exposure. Exposure to brackish water caused an increase in the flexural strength by virtue of buildup of barnacles, which protected the specimens from deterioration and increased the strength by acting as an additional reinforcement.