1) Lime: It makes the cement sound and strong. The lime in excess quantity makes the cement unsound and cause the cement to expand and disintegrate.
2) Silica: It provides strength to the cement due to the formation of dicalcium and tricalcium silicates. The silica in excess quanity causes the cement to set slowly.
3) Alumina: It provides quick setting property to the cement and lowers the clinkering temperature.
4) Iron Oxide: It provides colour, hardness and strength to the cement. It also helps the fusion of raw materials during the manufacture of cement.
5) Magnesium Oxide: It provides hardness and colour to the cement, when present in small quantity. The magnesium oxide in excess quantity makes the cement unsound.
6) Sulphur trioxide: It makes the cement sound, when present in very small quantity. The sulphur trioxide in excess quantity makes the cement unsound.
7) Alkalies: These should be present in small quantities. The alkalies in excess quantity will cause efflorescence.