Environmental effects on the short-term bond of carbon fiber-reinforced polymer (CFRP) composites

Carbon fiber reinforced polymers (CFRP) are being increasingly used in many structural applications due to their excellent mechanical and corrosion resistance characteristics. CFRP sheets and strips are being used to strengthen waterfront concrete structures, such as piers and wharves. The CFRP reinforcements are bonded to beams, piles, and decks using structural adhesives. Adhesive strength can be affected by both short-term and long-term environmental exposure. In the current study, short-term effects of temperature, moisture, and chloride content on the CFRP adhesion are evaluated using pull-off tests. Three structural adhesives were chosen to assess the effects of three different temperatures and four different relative humidities on the CFRP adhesion to concrete cubes. In the case of concrete piles exposed to marine conditions, the effect of superficial chloride content on the short-term bond strength was also investigated. It was shown that high relative humidity may reduce bond strength below acceptable levels.