Types of Recycled Aggregate
Recycled stone, concrete and asphalt represent the largest source of recycled aggregate in use in the world today. These materials come from demolished buildings, railways, roads and pavements. The concrete and other materials are broken up and sent to processing plants, where they are crushed into gravel-sized particles. In some areas, paving crews may bring crushing equipment on-site and crush materials as they are demolished.
Recycled rubber and construction materials can be used in place of traditional gravel in paving or sub-base applications. This rubber comes from crushed tires or scrap rubber left over from industrial and manufacturing facilities. Rubber materials mixed with traditional recycled stone could be used as an effective form of aggregate in lightweight concrete applications.
Many different types of industrial furnace byproducts can be used to replace sand and other fines in concrete. For example, coal-burning power plants produce a material known as fly ash, which serves as a popular replacement for aggregate in recycled concrete.
Crushed glass serves as an effective aggregate in lightweight concrete applications. The glass may be ground down to a sand-like texture or left in larger chunks the size of gravel. Glass aggregate may be left exposed in the surface of some recycled concrete applications to give the concrete an attractive and unique finish.