Fiber Reinforced Geopolymers for Fire Resistance Applications

This paper presents the development of fiber reinforced metakaolin-fly ash based geopolymers for fire resistance application. A series of experiments are carried out to develop optimum mix proportions of fiber reinforced metakaolin-fly ash based geopolymers with superior fire resistance properties. Bending and compression tests were conducted at ambient temperature and after exposure to elevated temperatures on geopolymers with different proportion of carbon fiber and fly ash substitution for metakaolin, and the effect of carbon fiber and fly ash content were quantified. Data from the tests showed that the addition of chopped carbon fibers in geopolymers provides effective crack control and enhances bending strength under high temperature. Further partial substitution of fly ash for metakaolin reduces the water demand in the reaction process on geopolymer preparation and microstructure damage under high temperatures due to evaporation of water present in geopolymers, thus enhance the mechanical properties of geopolymers after exposure to elevated temperatures. Based on these experiments, a geopolymer made with 50% metakaolin and 50% fly ash and reinforced by 2% chopped carbon fibers can be an effective alternative material for structures in fire resistance applications.