what are aggregates

Aggregates are granular materials that are used in construction and are obtained from natural sources such as sand, gravel, crushed stone, and recycled concrete. They are the most mined materials in the world and are used as a component of composite materials such as concrete and asphalt, where they serve as reinforcement to add strength to the overall composite material. Aggregates are also used as a stable foundation or road/rail base with predictable, uniform properties, or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. They are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains due to their relatively high hydraulic conductivity value as compared to most soils. Aggregates are also used in the water filtration and purification process, as well as air filtration and erosion control. In summary, aggregates are an essential ingredient in the construction industry and are the building blocks of our society.