Aggregate is a granular material that is used in the construction of buildings and other structures. It is composed of inert materials such as sand, gravel, crushed stone, slag, and recycled aggregates. Aggregates are used to increase the volume of building materials, as they are much cheaper than cement. They also provide strength, durability, and hardness to the structure.
Aggregates are usually composed of coarse-grained gravel or crushed rocks and fine materials. The purpose of aggregate is to fill the voids in the coarse-grained material and act as a workability agent. It also helps to reduce cracks and increase the strength of the structure. The properties that define the quality of the aggregate are important for its use.
The use of larger maximum size of coarse-grained aggregates reduces cement and water requirements. Fine aggregate generally consists of sand, crushed stone, or crushed slag screens; coarse-grained aggregate consists of gravel (pebbles), broken stone fragments, slag, and other coarse-grained substances. For greater workability and economy, as reflected in the use of less cement, the fine aggregate must have a rounded shape. Aggregate materials are used in buildings and constructions to be mixed with cement, bitumen, lime and gypsum to make concrete or mortar.