What are the three components of modern concrete?

• A. Portland cement, aggregate, and water
• B. Lime, sand, and water
• C. Portland cement, water, and steel
• D. Gravel, lime, and wax

Answer: (B)

Concrete in modern construction is a composite made from a binder, water, and aggregates. The binder is Portland cement, which reacts with water in a hydration process to form a hard, solid matrix that holds everything together. Aggregates, including fine sand and coarse gravel or crushed stone, fill volume, improve strength, and reduce shrinkage. Water activates the cement’s hydration and also influences workability and strength as the mix cures. In reinforced concrete, steel may be added to improve tensile strength, but it’s not one of the basic three constituents of the mix itself. Lime-based mixtures and traditional lime mortar use lime as the binder, not Portland cement, and wax or other additives aren’t standard components of modern concrete. So, the three components of modern concrete are cement (Portland cement), water, and aggregates.