Fly ash-based geopolymer chemistry and behavior

This chapter provides an overview of fly ash-based geopolymer materials. Key parameters that must be considered when using a fly ash as the raw material for geopolymer production are discussed, including fly ash chemical composition, amorphicity, and morphology. In addition, external parameters that lead to the final mechanical, structural, and durability properties of fly ash-based geopolymers are introduced. The current, updated structural descriptions of the phases formed in this system are presented, including the new structural model of the main sodium aluminosilicate hydrate (N–A–S–H) gel. Finally, key drivers towards commercialization of fly ash-based geopolymer materials are discussed, including adoption of performance based standards.