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The most popular matrix used for fiber-reinforced industrial composites is organic polymer. The nature flammability of the organic polymer matrix (Marsh, 2002), however, limits the use of these materials in ground transportation (Hathaway, 1991), submarine and ships (Demarco, 1991), and commercial aircraft (Davidovits, 1991), where restricted egress of fire hazard is an important design consideration, although traditional fibers, such as carbon and glass fibers or new developed, high temperature, thermal-oxidative stable fibers from boron, silicon carbide and ceramic are inherently fire resistant (Papakonstantinou et al., 2001). In other word, most of organic matrix composites cannot be used in applications that require more than 200 oC of temperature exposure. In these cases of applications, composites based on carbon matrix or ceramic matrices are being exploited. However, use of these materials is even strongly limited, due to high cost accompany with special and high-thermal processing requirements (Papakonstantinou et al., 2001; Papakonstantinou & Balaguru 2005). In 1978, Joseph Davidovits proposed that binders could be produced by a polymeric reaction of alkaline liquids with the silicon and the aluminum in source materials of geological origin or by-product materials such as fly ash and rice husk ash (Davidovits, 1999). These binders have been coined as term geopolymers since 1979; they are inorganic polymeric materials with a chemical composition similar to zeolites but without defined crystalline structure and possessing ceramic-like features in their structures and properties. The amorphous to semi-crystalline three dimensional of sialate network consists of tetrahedral SiO4 and AlO4 which are linked alternately by sharing all the oxygens to create polymeric Si-O-Al bonds (Davidovits & Sawyer 1985; Davidovits, 1991). Geopolymers are still considered as a new material for coatings and adhesives, a new binder for fiber composites, and a new cement for concrete (Davidovits, 2008). They are mineral polymers and the essence of all mineral polymers is never burn (Davidovits, 2008). Therefore, we can state that geopolymer materials are ideal for high temperature and fire applications. Fiber-reinforced composites based on geopolymer matrix (geocomposite) have been wellknown for over 20 years, since the first Davidovits’ patent was filed (Davidovits et al., 1989). |
