Effect of the environment on the performance of GFRP reinforcing bars

Fiber reinforced Polymer (FRP) composites are currently employed in the civil engineering industry as externally bonded reinforcement (EBR) of existing reinforced concrete (RC) and masonry structures and as internal reinforcement of concrete elements as an alternative to steel reinforcing bars. Carbon FRP (CFRP) composites are mainly used for EBR applications whereas glass FRP (GFRP) bars are employed as internal reinforcement of concrete elements. This paper sheds light into the effect of different aggressive environments on the tensile behavior of reinforcing GFRP bars. 356 results of tensile tests of GFRP bars subjected to hot dry and humid air, different alkali environments, salt solutions with various concentrations, and plain and distillated water were collected from the literature. According to the “design by testing” procedure provided by EN 1990, a statistical analysis of the results was carried out to calibrate environmental reduction factors able to provide reliable estimations of the long-term behavior of GFRP bars subjected to different exposure conditions. For a given aggressive environment, a clear and unique degradation trend could not be identified, which points out the need of a standard testing procedure able to provide reliable and repeatable results.