Effect of Environmental Conditions on Bond Strength between CFRP Laminate and Concrete Substrate

Synopsis: Limited information is known about the effects of environmental conditions during installation on quality and performance of the bond between carbon fiber reinforced polymer (CFRP) reinforcement and substrate material. This research study investigates the effect of surface moisture, relative humidity and temperature on the bond strength between concrete and CFRP reinforcement. Three test methods including a surface pull-off bond test, a surface shear-torsion bond test, and a flexural test were used to evaluate the bond performance of the FRP fabric under various installation conditions. Test results revealed that the high surface moisture content, extreme humidity and extreme low temperature can be detrimental to bond strength. Although the high temperature improved the bond strength, it is not recommended because of decreased set-time and saturant workability. Based on the results presented in this paper, a maximum allowable limit on surface moisture content, relative humidity, and temperature of 4.3%, 82%, and 90F, respectively, at installation is recommended.