The document discusses the manufacturing process of cement. It begins with crushing and mixing of raw materials such as limestone, clay, and iron ore. The raw materials are then heated in a kiln to form clinker. Clinker is ground into a fine powder to produce cement. When mixed with water, cement undergoes chemical reactions that result in hardening over time as it hydrates. The hydration process involves calcium silicates and aluminates reacting with water to form compounds like calcium silicate hydrate and calcium aluminate hydrates.

1. CEMENT Dr. Prashant Mehta Assistant Professor, National Law University, Jodhpur

4. PORTLAND CEMENT COMPOSITION Lime (CaO) 60-66% Excess reduces strength and make cement disintegrate and in less amount reduces strength and makes it quick setting. Silica (SiO 2 ) 17-25% Provides strength to cement Alumina (Al 2 O 3 ) 3-8% Helps in quick setting Calcium Sulphate (Gypsum) Enhances initial setting of cement Iron Oxide 2-6% Gives color, Strength and hardness. Sulphur trioxide (SO 3 ) 1-3% Provides soundness Alkali Oxides (Na 2 O and K 2 O) 0.5-1.5% in excess makes cement efflorescent Magnesium Oxide (MgO) 1-5%