Comparative performance of Fibre Reinforced Polymer and Fibre Reinforced Cementitious Mortar Strengthening Systems in Elevated Temperature Service Environments

Fibre reinforced cementitious mortar (FRCM) strengthening systems have recently emerged as novel means of strengthening damaged or deficient masonry and/or concrete structures. These unique systems consist of open-weave polybenzoxozole (PBO) fibre fabrics which are applied to the surfaces of structural elements, walls, domes, tunnels, or shells using specialized inorganic cementitious mortars. FRCM systems have a number of advantages over alternative strengthening systems such as externally bonded fibre reinforced polymers (FRPs), most notably their breathability, inherent non-combustibility, non-flaming characteristics, and their performance in elevated service temperature environments. However, while FRCM systems have seen some application in Europe, additional research is needed, most importantly on their high temperature performance and durability, before they can be widely applied with confidence. This paper reports the initial results of an ongoing experimental study into the performance of a specific FRCM structural strengthening system for concrete. Tests on strengthened small scale concrete beams at ambient and elevated temperatures are presented. A comparison against currently available externally bonded FRPs is included. The superior bond performance of FRCM strengthening systems at elevated temperatures of between 50ºC and 80ºC is clearly demonstrated.