C hemical C omposition:- Ordinary cement contains two basic ingredients, namely, argillaceous and calcareous. In argillaceous materials, clay predominates and in calcareous calcium carbonate predominates. Broadly, the raw materials used for manufacture of cement consist mainly of lime, silica, alumina and iron oxide. These oxides interact with one another at high temperature and form more complex compounds. The relative proportions of these oxide compounds are responsible for influencing the various properties of cement, in addition to rate of cooling and fineness of grinding. F unctions O f C ement I ngredients 1. Lime (CaO): Excess lime makes the cement unsound and causes the cement to expand and disintegrate. Deficiency in lime makes loss of strength and makes cement to set quickly. 2. Silica (SiO2): SiO2 imparts the strength to cement by forming the di-calcium and tri-calcium silicates. Excess silica makes the strength of cement increases,but prolongs the setting time. 3. Alumina (...