Aggregates are raw materials that are produced from natural sources and extracted from wells and quarries, such as gravel, crushed stone and sand.
Aggregateis a term given to a collection of granular building materials used to create concrete slabs and form surfaces and substrates. It is commonly used in residential and commercial projects for drainage, filling voids, protecting pipes, and providing hard surfaces. The same rating size is used for larger armor stone sizes in EN 13383, EN 12620 for concrete aggregate, EN 13242 for road construction base layers and EN 13450 for railway ballast.
Aggregates are a very critical and important component of high-density concrete and are mainly composed of crushed minerals that contain relatively heavy elements, in combination with various additives, but can also include scrap steel or certain ceramics. For example, Ring Industrial Group's EZFlow product lines are produced with geosynthetic aggregate parts containing more than 99.9% recycled polystyrene. Due to the relatively high hydraulic conductivity value compared to most soils, aggregates are widely used in drainage applications such as foundation drains, French drains, septic drainage fields, retaining wall drains, and roadside drains. Aggregates are also a component of composite materials such as concrete and asphalt; the aggregate serves as reinforcement to add strength to the overall composite material.
For greater workability and economy, as reflected in the use of less cement, the fine aggregate must have a rounded shape. When stone, sand, and gravel are not available, construction demand is generally met by shipping aggregates by rail, barge, or truck. The aggregate demand by sector of the final market was 30 to 35% for non-residential buildings (offices, hotels, shops, manufacturing plants, government and institutional buildings, and others), 25% for roads and 25% for housing. Specialized aggregates are required for use in certain demanding applications, especially when lightweight members are required in constructions or when heavy, high-density materials are needed.
To ensure that the aggregate is inert, it is manufactured from materials that have been tested and characterized according to European waste codes. Aggregates are generally not affected by climate as much as soils, particularly clay soils, and will not suffer shrinkage cracking during dry periods. Aggregate is granular material such as sand, gravel, crushed stone, crushed hydraulic cement concrete or iron blast furnace slag that is used with a hydraulic cementing medium to produce concrete or mortar. Aggregates greatly influence freshly mixed and hardened concrete properties, mix ratios and economy.
Recycled concrete is a viable source of aggregate and has been successfully used in granular subbases, soil cement and new concrete.