ABSTRACT
The synthesis of geopolymers relies on the following reactions (Xu and van Deventer, 2000).
The structure of geopolymers can be either amorphous or crystalline, depending on the condensation temperature.Amorphous polymers are obtained at temperatures ranging from 20 to 90◦C, while crystalline polymers are obtained at 150-200◦C. The structure of crystalline geopolymers resembles that of zeolite A (Davidovits, 1991).Geopolymeric materials are attractive because they have excellent mechanical properties, fire resistance and durability (Davidovits and Davidovics, 1988; Palomo et al., 1992). Furthermore, the reaction pathway requires either metakaolinite, obtained by calcining kaolinite at temperatures of the order of 600-700◦C, or raw silicoaluminates. There is thus great interest in the reduced energy requirement for the manufacture of new materials based on geopolymers.
