Mechanical properties and fire response of GEOPOLYMER structural composites

One of the major concerns in using Fiber Reinforced Composites in applications that might be subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200°C. This paper deals with the development and use of a potassium aluminosilicate (GEOPOLYMER) that is inorganic and can easily sustain more than 1000°C. The results presented include the composite behavior in tension, flexure, and shear. Tests have been conducted on the virgin samples and samples exposed to temperatures from 200 to 1000°C. The results indicate that the composite can withstand 327, 245, and 14 MPa in tension, flexure, and shear respectively. It retains about 63 percent of its original flexural Strength at 800°C. The fire response of the carbon fiber composite was measured and the results compared to organic matrix composites being used for infrastructure and transportation applications. At irradiance levels of 50 kW/m² typical of the heat flux in a well developed fire, glass- or carbon-reinforced polyester, vinylester, epoxy, bismaleimde cyanate ester, polyimide, phenolic, and engineered thermoplastic laminates ignited readily and released appreciable heat and smoke, while carbon-fiber reinforced GEOPOLYMER composites did not ignite, burn, or release any smoke even after extended heat flux exposure.