New WRAP Study Compares Leaching Performance of Recycled and Secondary Aggregates in Concrete
New research published by WRAP (Waste & Resources Action Programme) has shown the leaching performance of concrete containing recycled and secondary aggregates to be similar to concrete made using aggregates from primary sources.
The study provides guidance and reassurance in an area where little information has been available to date and enables UK contractors and specifiers to further embrace the use of sustainable aggregates in concrete.
Using a variety of secondary and recycled aggregates - including recycled asphalt planings, foundry sand, incinerator bottom ash, crushed concrete and crushed brick - the report analysed the potential for elements within the aggregates to be leached from concrete into controlled waters such as groundwater and drinking water.
The study also determined that the best method of evaluating the suitability of recycled and secondary aggregates for use in concrete (in relation to their release of undesirable substances) was testing the material in accordance with BS EN 1744-3:2002. This refers to a rapidly stirred tank test carried out on crushed aggregate material and is based on the assumption that equilibrium or near-equilibrium is achieved between the liquid and solid phases during the test period.
John Barritt, technical advisor for aggregates at WRAP, explained: “Recycled and secondary aggregates have a key role to play in making the construction industry more sustainable and it’s therefore important the industry is able to have full confidence in using these materials. It’s also important the materials are shown not to have an adverse impact on either the properties of concrete or the environment in which they are used. We were pleased to note the study found the performance of both primary aggregate and aggregates that come from recycled and secondary sources to be very similar. We also identified a reliable testing method that can be used to determine the likely leaching performance of individual aggregates when used in concrete.”
To download the full report - Testing of Concrete to Determine the Effects on Groundwater – visit WRAP’s comprehensive AggRegain website – http://www.aggregain.org.uk/.
For further information on WRAP, visit the website www.wrap.org.uk/construction or call the construction team on 0808 100 2040
Editor's notes:
- WRAP works in partnership to encourage and enable businesses and consumers to be more efficient in their use of materials and recycle more things more often. This helps to minimise landfill, reduce carbon emissions and improve our environment.
- Established as a not-for-profit company in 2000, WRAP is backed by Government funding from Defra and the devolved administrations in Scotland, Wales and Northern Ireland.
- Working in seven key areas (Construction, Retail, Manufacturing, Organics, Business Growth, Behavioural Change, and Local Authority Support), WRAP’s work focuses on market development and support to drive forward recycling and materials resource efficiency within these sectors, as well as wider communications and awareness activities including the multi-media national Recycle Now campaign for England.
- As part of WRAP’s Construction focus, the Aggregates Programme is funded by Defra through the Aggregates Levy Sustainability Fund (ALSF) and by the Scottish Government to reduce the demand for primary aggregates by promoting the use of recycled and secondary aggregates.
- More information on all of WRAP’s programmes can be found at www.wrap.org.uk
