Recycled & Secondary Aggregates

An essential contribution to the circular economy

Recycled and secondary aggregates are making an increasingly important contribution to the UK's needs..

By reducing demand on primary aggregates, they are helping the industry to become more sustainable - in other words, not using up assets today that our children may need tomorrow

The UK utilises 70 mt of recycled and secondary materials in the GB aggregates market, this contributes 28% market share which is three times higher than the European average, highlighting the fact that the use of recycled and secondary materials in Britain is close to full potential.

Recycled aggregates

Construction will often require demolition of existing buildings and structures built with hard and durable materials such as concrete and brick which can be recycled and re-used in new construction.

Recycled aggregates are the product of processing inert construction and demolition waste, asphalt planings and used railway ballasts into construction aggregates. Just as primary aggregates, these materials conform to European aggregate standards and national specifications, and make a key contribution to total aggregates demand.

Construction activity can also require excavation work such as groundworks and tunnelling which generate softer materials including soils, sub-soils and clays which can be used for quarry restoration.

Secondary materials

Secondary materials are derived from other industrial processes including:

Colliery spoil - widely used for bulk fill
China clay waste - used in some areas as mortar and concreting sands
Power station ash (Fly Ash - FA) - used as a cementitious addition within Ready Mixed concrete and as an aggregate in block manufacture
Incinerator Bottom Ash (IBA) from municipal solid waste incineration. It may contain glass, ceramic, brick, concrete, grit and stone in addition to clinker. It is generally used in construction applications to replace primary aggregates in utilized as fill material/sub-base, for road construction or in block manufacture
Blast furnace slag from the iron and steel industries - used as aggregates and when ground to form GGBS as cementitious materials
Slate

Collectively, these materials contribute significantly to the total aggregates demand across the whole UK Market.

Key technical publications

Challenges to be faced

The challenges that go with recycled and secondary aggregates are threefold:

Environmental - recovery of some wastes that have become part of a local landscape can have environmental consequences. Slate tips are an example
Technical - the wider implementation of the WRAP Quality Protocol first introduced in 2004 is increasing the credibility of recycled aggregates. However continued effort is required to instil confidence with the recycled aggregate across the full range of private and local authority customers. Prior to the introduction of the Quality Protocol, the lack of adequate technical specifications and control has previously inhibited the wider acceptability and use of recycled materials.
Economic - recycling isn't always cheaper. The recent significant increases in transport costs added to the costs of selection and processing, can make recycled aggregates prohibitively expensive

Please note this website is maintained to provide information and guidance on UK issues, products and applications of those products.

WRAP Guidance on the Quality Protocol requirements for the production of aggregates from inert waste:

Downloads

The Environment Agency is currently reviewing the WRAP protocol for the production of aggregates from inert waste and MPA are at the forefront as the industry voice on recycled and secondary materials for aggregate production.