Mechanical Properties of FRCM at High Temperatures

Fibre-Reinforced Polymer (FRP) sheets are commonly used to increase the load-carrying capacity and stiffness of deficient structural members; however, there are concerns regarding the use of unprotected FRP in strengthening applications when exposed to fire. Fabric Reinforced Cementitious Matrix (FRCM) systems have emerged as a promising alternative for strengthening applications, replacing polymeric resins such as epoxy with an inorganic cementitious matrix. Although FRCM systems are generally expected to perform more favourably in fires because the cementitious matrix protects the fibres from direct exposure to elevated temperatures, limited experimental data is available to quantify the effect of temperature on its mechanical properties. This paper first presents a review of available literature on FRCM and identifies the parameters influencing the properties of FRCM at room and high temperatures. This sets the path for experimentally investigating the tensile behaviour of FRCM coupons under different heating regimes, namely: steady-state and transient temperatures. Progress is presented to-date on a study of the mechanical properties of carbon FRCM specimens, including tensile strength and modulus of elasticity, during exposure to elevated temperatures. The variables in the experiments include the number of layers of fabric (1, 2, 3 layers) in the composite test specimens, the thickness of the specimens (20, 30 and 40 mm), the fabric orientation (unidirectional vs. bidirectional), and the exposure temperatures. Results from a preliminary heating test shows a significant thermal gradient through the FRCM sample. The results are expected to enhance the understanding of the FRCM behaviour under heat effects.