In Construction, What Is Aggregate?

In construction, aggregate describes a variety of materials including gravel, sand, and crushed stone. These particles are used in their raw form or are combined with other materials to produce concrete or asphalt. Aggregates are readily recyclable and are usually reused for new construction. Construction aggregate is a multi-billion dollar industry.

An aggregate is the individual component within a material. It typically provides bulk for the material or prevents stress caused by compression. Gravel, for example, is considered an aggregate of concrete. It has a specific particle size of 0.079 to 2.5 inches (2-64 mm). Sand is another aggregate of concrete with a particle size of 0.0025 to 0.0787 inches (0.0625-2 mm).

When combined with other materials, aggregate particles provides support for an entire structure. In cement, gravel and sand together provide the right support when the mix hardens. The aggregate in asphalt provide a similar role.

Aggregates find there way into several applications. For example, gravel is used to pave some road types and provides support for railroad tracks. Sand is used in agriculture to grow crops and along the shore to replenish beaches that have been eroded by waves. Crushed stones are another type of aggregate used in road construction.

Most types of aggregate is recyclable. The aggregate is usually sorted out after old buildings have been demolished or concrete blocks have been broken down. These aggregates are recycled for building new roads or some other type of construction. This could include housing, buildings, or industrial facilities.

Several companies manufacture aggregates. They usually mine the materials from granite, trap rock, and limestone. The process begins with blasting and drilling to reduce the size of the rocks. Eventually the rocks are reduced in size to fit the descriptions for gravel, sand, and crushed rock.

Most companies market aggregate for infrastructure projects. Much of the aggregate is used as base material for highways, runways, walkways, and parking lots. They can also be combined with other raw materials to build structures.

Another way companies market this substance is in making the case for erosion control along water canals. Aggregate constituents also aid in water purification and filtration. As water passes through small rocks, impurities generally are filtered out of the water.

Aggregate can be used in a many areas. On average, each American will generally use eight tons of aggregate each year, according to Vulcan Materials Company. This takes into account all the aggregate material in roads and walkways.