Guide

Recovering and using recycled aggregates

Geosystems and recycled and secondary aggregates

Geosystems are composite systems installed and working in the ground. They contain three elements:

  • Engineering input - generally refers to professional, technical and design guidance.
  • Soil - any type of unconsolidated fill material, either granular or cohesive. Types of fill that can be used in geosystems include excavated arisings, imported recycled or natural aggregates, weathered rock and soft clay sediments.
  • Geo-components - an engineered product, sometimes geo-synthetically based, that is used in a geosystem. Engineered geo-components are manufactured elements such as steel meshes, strips, textiles, boxes and tubes, polymers, natural fibres, concrete and timber. They are used to provide a specific function within the geosystem, such as containment or reinforcement of the soil, or additional drainage.

Recycled and secondary aggregates can be used within geosystems for:

  • steep slopes and retaining walls
  • ground stability and retaining walls
  • road pavements
  • working platforms for crane or heavy plants
  • erosion control of water courses or embankment slopes
  • geotubes for erosion protection or filtration
  • marine applications
  • landfill applications

Benefits of using geosystems

Geosystems generally use resources much more efficiently than traditional ground improvement solutions in civil engineering, such as using concrete or steel.

Geosystems have the potential to deliver good cost and environmental benefits, including shorter construction times and reduced carbon emissions.

Geosystem standards and design

The British Standards Institution (BSI) has published BS EN 14475:2006 Execution of special geotechnical works (reinforced fill), which covers the design and criteria of geosystems. You can buy a copy of BS EN 14475:2006 on the BSI website.

It is a good idea to get help from an independent design professional to check that the manufacturer's or supplier's suggestions for building solutions comply with any relevant design codes or environmental requirements.