Durability of CFRP-Wrapped Concrete Exposed to Hydrothermal Environment

Abstract

In recent years, it has become increasingly common to strengthen concrete by wrapping carbon fibre reinforced polymer (CFRP) laminates to improve its compressive strength and ductility. However, studies on the durability of CFRP-confined concrete are relatively scarce, which could significantly hinder the application of CFRP in structural reinforcement. An experimental study was conducted to investigate the effect of exposure to natural hydrothermal environment on the confinement system of CFRP-wrapped concrete in this study. Three kinds of specimens were prepared and tested after natural exposure to the subtropical environment in South China, including 35 CFRP flat coupons, 35 epoxy adhesive flat coupons and 60 CFRP-wrapped concrete cylinders. The test parameters included the exposure duration (0, 6, 12, 18 and 30 months) for all specimens and the number of CFRP layers (0, 1, 2 and 3) for the CFRP-wrapped concrete specimens. Based on the experimental results, a compressive strength model for the CFRP-confined concrete exposed to hydrothermal environment was proposed. The results show that hydrothermal environment had a significant effect on the mechanical properties of the epoxy adhesive, but a relatively slight effect on that of the CFRP. Due to the deterioration of the CFRP, the compressive strength of CFRP-wrapped concrete gradually decreased with the increase of exposure duration. After a 30-month exposure, the compressive strength of CFRP-wrapped concrete has a decrease of approximately 10%.