Defined recovery of recycled aggregates

There are numerous environmental regulations that deal with the recycling of mineral waste – including bottom ash from waste incineration, waste and by-products from industrial processes or construction and demolition. The protection of soil and groundwater is always decisive for the use of these secondary materials.

Environmental regulations for substitute construction materials

Until the enactment of the nationwide regulation in form of the “Ersatzbaustoffverordnung” (Directive on Secondary Aggregates) on 1 August 2023, requirements pertaining to secondary construction materials are applicable on a German federal state level. With regard to the recycling possibilities of mineral waste, most federal states refer to the 1997 and 2003 guideline LAGA M20 of the “Länderarbeitsgemeinschaft Abfall” (i.e. the waste working group of the federal states), but there are also federal states with their own regulations, e.g. North Rhine-Westphalia (NRW) has created its own legal basis for use in applications and quality monitoring through a number of decrees. 

How exactly the individual material qualities are defined, which parameters are determined and how – the details can be found in our German handbook.

Differentiation of material classes

The environmental guidelines define specific material quality classes based on the environmental characteristics of recycled aggregates.

  • LAGA M20 differentiates between the following assignment values:
    • Z 1 with subcategories Z 1.1 and Z 1.2
    • Z 2
  • In its own decrees for recycled aggregates, NRW distinguishes between two classes of material:
    • RCL I
    • RCL II
Recycled aggregates are differentiated between material classes

Local conditions for the use of recycled aggregates

The protection of soil and groundwater is the essential condition for the use of recycled building materials. In general, a distinction is made between applications inside and outside of official water protection areas.

  • The use outside of water protection areas is permitted.
  • The use of recycled aggregates is prohibited in water protection areas WSG I and II.
  • The use in water and flood protection areas of the categories WSG IIIA/HSG III and WSG IIIB/HSG IV is permitted, but requires detailed individual consideration.
  • The distance to the groundwater level should amount to at least 1 m; it should reach at least 2 m for classification value Z 1.2 according to LAGA M20.
  • In individual cases and depending on the federal state, it may be possible to reduce the required distance to groundwater.