What are the two components of concrete?

• A. Cement and water
• B. Aggregate and paste
• C. Sand and gravel
• D. Reinforcement and cement

Answer: (B)

Concrete is a composite material made of a binding paste and an aggregate. The binding paste comes from cement mixed with water; it hydrates and hardens to hold everything together. The aggregate consists of inert granular materials like sand and gravel, which provide volume and strength. So the two components are the paste and the aggregate. Options that list cement and water describe only the paste, sand and gravel describe only the aggregate, and reinforcement isn’t a component of the concrete mix itself.