CSH phases are formed from calcium silicate (CS) phases [e.g., “alite” (Ca3SiO5, “C3S”), “belite” (Ca2SiO4, “C2S”), jennite (Ca9Si6O18(OH)6·8H2O) and tobermorite (Ca5Si6O16(OH)2·4H2O or Ca5Si6(O,OH)18·5H2O)] by hydration, and these phases are responsible for the hardening effect of cement. Common CSH phases are calcium silicate hydrate (CSH) and ettringite (Ca6Al2[(OH)12(SO4)3] . 26H2O). Lime (CaO) has been used for centuries as a stabilizer for soft clay treatment and improvement. It is generally believed that lime can slowly react with clay minerals to produce CSH and CAH phases that act as binders to contribute to the strength development of clayey soils.
Cf., calcium aluminate hydrate (CAH) phases, clinker, calcium silicate (CS) phases, hardening