Effect of temperature and humidity on long-term bond performance between CFRP and concrete

Fibre Reinforced Polymers (FRP) have emerged as one of the most promising and affordable solutions for strengthening civil engineering infrastructures. Nowadays, this application is widely used in outdoor structures such as bridges. The major challenge in composites applications for outdoor structures is the long-term durability of bond between FRP and substrate under different environmental conditions. Elevated temperature and humidity are common issues which may have adverse effects on the polymer matrix, especially on thermosetting adhesives such as epoxies. In this study, the long-term bond performances of Carbon Fibre Reinforced Polymer (CFRP) strengthened concrete members were evaluated. These specimens were exposed to combination of cyclic temperatures (20 degrees C - 50 degrees C) and 90% constant humidity. In addition to environmental exposure, some of the specimens were subjected to sustained loading. At the end of the exposure period, residual strength was determined using single shear test method. This paper presents the preliminary results of an experimental program being conducted to determine the bond performances under accelerated environmental exposures.