The Concrete Technology Unit at Dundee University, came to its conclusion after assessing the performance of recycled aggregates blended with natural aggregates, in concrete.
The research, commissioned by the government's recycling delivery body, the Waste and Resources Action Programme (WRAP), aimed to overcome barriers to using such recycled material in construction products.
John Barritt, WRAP's aggregates technical advisor, said: “This project report provides the technical detail required to increase the use of recycled aggregate in concrete, giving industry greater confidence and informing future revisions to the concrete standard.”
The report is not yet available on WRAP's website, but should be available soon.
Sustainability
Mr Barritt told letsrecycle.com that recycled and secondary (recovered materials such as fly ash) aggregates now make up 25% of the total demand for construction aggregates. He said this has increased over the last 10 years because of “landfill tax, the aggregates levy and the sustainability agenda.”
He added: “The specifications at the moment limit the type and amount of recycled and aggregates that can be used in concrete. This report shows that it can be used safely and economically in concrete which will hopefully influence a change in the British standard.
“Existing standards are not keeping up with the technology. The report is looking at the potential of using the material in higher value applications,” he said.
Researchers tested 125 concrete mixes and drew up three classes of recycled aggregate:
- Class A – can be used in a wide range of concrete including that used in marine environments
- Class B – suitable for moderate exposure conditions, most combinations of aggregate expected to fall in here
- Class C – restricted to mildest exposure conditions
Subscribe for free