What materials make up concrete?

Concrete is fundamentally composed of three primary materials: Portland cement, water, and aggregate. Portland cement serves as the binding agent that, when mixed with water, undergoes a chemical reaction called hydration, allowing it to solidify and gain strength. The aggregate, which includes materials such as sand, gravel, or crushed stone, provides volume and stability to the mixture. It is essential for achieving desired properties in concrete, such as strength, durability, and workability.

The correct answer emphasizes this classic composition, which is widely recognized in construction and fire service contexts as the foundational elements of concrete. Understanding these materials is crucial because it directly relates to many aspects of building construction, including load-bearing capabilities and potential fire behavior. An in-depth grasp of concrete composition helps fire service professionals assess structural integrity and risk when responding to emergencies involving concrete structures.