Secondary Aggregate
The MPA[1] define three types of Aggregate:
- Primary Aggregate - minerals that are extracted for aggregates use
- Recycled Aggregate - materials derived from Construction, Demolition and Excavation waste (mining waste) (CD&E Waste) including railway ballast
- Secondary Aggregate - materials which are the by-products of other industrial, production or extractive processes, including blast furnace iron and steel slags and Incinerator Bottom Ash (IBA)
Generally Secondary Aggregate is used in the ware used to describe both Recycled Aggregates from and or the description of any is sand and stone material that has been used previously and recycled or recovered to a Secondary Aggregate Specification. Further details on the waste that falls into this broad category is listed on the WikiWaste page Soil, Rubble, Hardcore.
In order to produce a Secondary Aggregate Specification a Quality Protocol was developed by the EA and WRAP in consultation with key stakeholders, including the construction industry, in 2004 in order to demonstrate how Construction and Demolition Waste could be processed to an appropriate quality and conform with a European Aggregate Product Standard and achieve an End of Waste Criteria. It can be downloaded from the Mineral Products Association website [2]
Secondary Aggregate can also be produced from the Soil, Rubble, Hardcore from Local Authorities - primarily from waste deposited by the public at Household Waste Recycling Centres (HWRC).