Environmental durability of externally bonded FRP materials intended for repair of concrete structures

This paper presents the results of an extensive study investigating the performance of fiber reinforced polymer (FRP) materials and FRP bond to concrete when subjected to various environmental conditioning regimes. An extensive experimental program investigated the behavior of three FRP systems subjected to nine different environmental conditioning protocols. The effect of environmental conditioning was assessed using four different standard test methods. The result is a consistently derived database encompassing 64 permutations of FRP material, test method, and environmental conditioning. Conclusions are drawn regarding both FRP system performance and the appropriateness of environmental conditioning protocols. Finally, a revised approach to establishing ACI-prescribed environmental knockdown factors is proposed.

Research highlights
► Three FRP systems subject to 9 conditioning protocols using four test methods.
► Best to poorest performance: CFRP plate, CFRP fabric, GFRP fabric; deterioration was more pronounced on bond properties.
► Elevated temperature conditioning can result in beneficial post-cure effects.