What is aggregate?
In civil engineering, an aggregate is the component of a composite material that is used to resist compressive stress.
An aggregate is typically a granular material, and includes things such as sand, gravel, crushed stone, crushed hydraulic-cement concrete, or iron blast-furnace slag.
There are two different types of aggregates, natural and artificial. Both serve the same purpose which is help the composite material, such as concrete be stronger and achieve special strength. They also help increase the volume of concrete and hence reduce cost. They also help provide dimensional stability, as well as influence hardness, abrasion resistance, elastic modulus and other properties of concrete to make it more durable, strong and cheaper