Use of Kaolin Clay as a Source of Silica in MgO–SiO2 Binder

Recent developments on the use of magnesium silicate (MgO–SiO2) as a potential binder material have been promising. Brucite, produced from the hydration of magnesium oxide, reacts with amorphous silica to produce magnesium silicate hydrate (M-S-H). Currently, silica fume is used as the primary source of silica in the majority of research into the M-S-H binder system. With increasing emphasis on sustainable construction, the identification and use of practical silica sources on a global commercial scale are imperative. The use of calcined kaolinitic clays, as supplementary cementitious material, has been widely established in the Portland cement industry and can also be used in production of magnesium silicate-based binder. In this study, the feasibility of using calcined kaolinitic clay alongside magnesium oxide was investigated. The effect of clay on the mechanical properties and hydration characteristics of the binder system are reported.