Portland cement is manufactured by heating limestone and clay at high temperatures. It is composed mainly of calcium silicates and is used widely in construction materials like concrete and mortar. Cement production involves mixing raw materials, burning them in a kiln to form clinker, grinding the clinker, and adding gypsum. When cement powder is mixed with water, it undergoes hydration and hardens into a strong building material. Reinforced cement concrete combines cement with aggregates and steel reinforcement to make structures able to resist both compressive and tensile stresses.