Performance of CFRP-Strengthened Concrete Beams after Exposure to Wet/Dry Cycles

This paper reports on the effect of exposure to cycles of wetting and drying in fresh and salt water on the performance of carbon fiber-reinforced polymer (CFRP)-bonded concrete beams. The test program included 3, 8, and 12 months of exposure of normal and high-strength concrete specimens strengthened with one and two layers of CFRP reinforcement. The results indicated that the exposure caused a reduction in the tensile strength and modulus of elasticity of the epoxy adhesive. The ultimate loads of the small-beam specimens were not significantly affected by the exposure owing to the redistribution of shear stress along the CFRP plates. The degradation of the CFRP-concrete interface, however, decreased the bond strength and fracture energy of CFRP strengthening systems in the small-beam test, especially in the one-layer high-strength concrete configuration. Insights on bond characteristics and failure mechanisms of CFRP-strengthened concrete under the tested exposure conditions are presented.