New UK guidelines on production of rubberised asphalt roads

Comprehensive research conducted by WRAP (Waste & Resources Action Programme) has proven for the first time that rubberised asphalt for UK road surfacing can be successfully produced using certain combinations of UK-sourced materials, including rubber crumb from used tyres.

This modified material has been found to offer a series of positive benefits when compared to conventional asphalt mixtures - but despite being used for highway construction in the US, South Africa, Australia and mainland Europe for many years, the material has never been applied in the UK.

In addition to providing a sustainable outlet for used tyres as a construction material, rubberised asphalt is also said to offer a selection of desirable qualities, ranging from increased durability and reflective crack reduction to increased skid resistance and improved flexibility.

Steve Waite, materials recycling project manager at WRAP, explained: “As the UK construction sector seeks more sustainable ways of working, there has never been a better time to identify new ways in which to incorporate recycled content into civil engineering projects. The findings of our research prove that rubberised asphalt can now be successfully applied as both a surface course and binder course in UK highways construction.  This opens the way for more widespread use of the material in this country and anybody looking to specify rubberised asphalt now has all the background information and technical direction they need.”

Initially, researchers analysed the information that was already available; collating practical experiences and learnings from overseas and identifying the range of practical issues associated with rubberised asphalt. From this point, a series of rubberised asphalt and control mixes were manufactured using a wide range of materials readily accessible in the UK. The materials used included Venezuelan and Middle Eastern bitumen and recycled tyre rubber crumb of different sized grades - recovered from both truck and car tyres - along with limestone, granite and gritstone as the aggregate material.

Ian Walsh from Jacobs (UK) Ltd, who acted as an advisor to WRAP during the research, added: “These results prove - for the first time in the UK - that it is possible to blend recycled tyre rubber and bitumen to create a useable, valuable binder. This alone is a very significant finding. But the results of the testing go so much further, demonstrating as well that different types of bitumen and recycled rubber can be used to create a wide range of mixtures that have been proven suitable for use as both surface and binder courses in highways construction.”

WRAP’s research has been published in a report entitled Rubberised Asphalt Testing to UK Standards. It can be downloaded free from the WRAP website: www.wrap.org.uk