Composition, hydration, setting and curing
Cements

Portland cement contains four main constituents:

• tricalcium silicate 3 CaO, SiO ₂ (or, by abbreviation, C ₃ S);

• dicalcium silicate 2 CaO, SiO ₂ (or C ₂ S) ;

• tricalcium aluminate 3 CaO, AI ₂ O ₃ (or C ₃ A) ;

• tetracalcium-alumino-ferrite 4 CaO, AI ₂ O ₃ , Fe ₂ O ₃ ...