
Aggregate
Aggregate is defined in British Standards as a granular material used in construction, which may be natural, manufactured or re-cycled.
Natural Aggregates or Primary Aggregates are naturally occurring materials of rock, sand and gravel. These are extracted directly from land or marine sources for use in construction.
Secondary Aggregates or Manufactured Aggregates are by-products of industrial processes such as steel slag or pulverised fuel ash from power stations.
Secondary Aggregates also include Mineral Wastes, which are materials arising as a by-product of mineral extraction. They are capable for use, either with or without further treatment, as a primary aggregate substitute, e.g. slate waste and certain crushed rock fines.
Recycled Aggregates are previously used materials that are capable of being substituted for primary aggregates. These include waste material from construction operations; the demolition of buildings or structures and railway ballast.