Concrete is a composite material made from cement, water, sand, and aggregates. When mixed and poured it hardens into a durable structure. It is used in foundations, slabs, walls, columns, bridges, and roads.
For a slab: length × width × thickness. For a column: π × radius² × depth. Complex shapes like stairs are calculated by combining simpler geometric forms. Results are shown in cubic meters, cubic feet, and cubic yards.
Standard concrete has a density of approximately 2,130 kg/m³. Bags are commonly available in 60 lb and 80 lb sizes. Always order slightly more than estimated to account for waste, spillage, and settling.
Concrete has a working time of 30–90 minutes after mixing. Hot weather accelerates setting; cold weather slows it. Prepare all forms before mixing. For large projects, ready-mix concrete is more consistent than hand-mixing bags.