Secondary construction materials: nature comes first

The use of secondary aggregates such as recycled aggregates from construction and demolition waste (CDM waste) or incinerator bottom ash is subject to detailed environmental regulations. When reusing such secondary building materials, the protection of groundwater and soil have priority – as stipulated in the Water Resources Act (WHG), the Federal Soil Protection Act (BBodSchG) and the Federal Soil Protection Directive (BBodSchV). 

Fundamental environmental regulation: Secondary Aggregate Directive

Based on a detailed scientific concept, the Secondary Aggregate Directive lays down the requirements for the production and use of substitute minerals (MEB) in road construction and earthworks throughout Germany. A distinction must be made when using MEB in landfill construction, in asphalt or concrete. For those areas of application, the EBV does not apply. In addition to defining potential recycling options, the EBV specifies the requirements for monitoring the quality of environmentally relevant parameters. Compliance with these parameters forms the basis for classification into two material classes, referred to as HMVA-1 and HMVA-2. 

Distinction of local conditions

The Secondary Aggregate Directive details possible application areas based on their importance for groundwater and soil protection. A distinction is made between the use of secondary aggregates inside and outside of water protection zones, mineral spring protection zones and water priority areas. 

  • The use of IBA in water protection zones WSG I and II is excluded.
  • The use in water and mineral spring protection zones WSG IIIA/HSG III and WSG IIIB/HSG IV and in water priority areas is generally possible.

In addition, it must be determined whether the soil type above the aquifer consists of gravel, sand or clay/silt. When the groundwater cover consists of gravel the use of secondary aggregates is generally not allowed. In this case, an artificial cover layer can be created if the authority approves.

The distance to the highest expected groundwater level must be at least 1.0 m. This value increases to 1.5 m for construction projects located within water protection areas.

Details regarding environmental requirements for using secondary aggregates in Germany are to be found on meb-services.de. Alternatively, make use of our information offer with videos and online training on meb-wissen.de