In 2019, Britain laid tyre-rubber asphalt on the M1; after successful trials, it won UK industry approval in 2021, with up to 750 waste tyres reusable per kilometre

Britain began testing an unusual solution to its mounting tyre waste in 2019, when Highways England and construction company Tarmac laid a road surface containing recycled tyre rubber on the M1 near Leicester, according to a UK government press release published that August. The trial tested whether granulated rubber from waste tyres could be incorporated into asphalt durable enough for a heavily trafficked motorway. Two years later, Tarmac said the material had secured BBA HAPAS Clause 942 approval for use on the UK’s strategic road network, marking a significant step towards its wider adoption.

From waste tyres to motorway surface

The original trial was carried out on the southbound M1 between junctions 23 and 22. Tarmac developed the asphalt by incorporating granulated rubber recovered from end-of-life tyres into the road mix.The experiment was designed to test whether the material could withstand the demands of one of Britain’s busiest road networks while also tackling a growing waste problem. At the time, Highways England said around 40 million waste tyres were generated in the UK each year. The 2019 trial was intended to assess whether using some of that material in roads could provide an alternative to exporting or otherwise disposing of used tyres. Rather than simply replacing conventional asphalt with whole tyres, the process uses processed tyre rubber as a component of the asphalt mixture.

How many tyres can one kilometre use?

Tarmac estimates that the rubber recovered from up to 750 waste tyres can be incorporated into each kilometre of highway, depending on the thickness of the road surface. Its current product information describes the material as a warm-mix asphalt containing recycled rubber crumb from end-of-life car tyres.That figure is an estimate rather than a fixed number for every road. The amount of rubber that can be incorporated depends on the design and thickness of the particular surface. The approach also gives old tyres another use within the UK rather than sending them overseas. Tarmac said in 2021 that the country was still exporting a significant share of its used tyres, making road construction an additional domestic route for tyre recycling.

From M1 trial to industry approval

The M1 experiment was not an isolated test. Tarmac said its rubber-modified asphalt had undergone a series of trials before the company announced in April 2021 that its ULTIPAVE R system had received BBA HAPAS Clause 942 approval.The approval is significant because Clause 942 covers thin surfacing systems used on roads, including the strategic road network. Tarmac described ULTIPAVE R as the first thin surfacing system of its kind in the UK to receive that approval.The British Board of Agrément’s certification record confirms that ULTIPAVE-R is a stone mastic asphalt incorporating ground tyre rubber and is assessed for use as a warm-mix surface course in new and maintenance road construction. The current certificate records the product as originally certified in August 2020.

More than just recycling

The rubber is only one part of the sustainability pitch. Tarmac’s ULTIPAVE R uses its ULTILOW warm-mix technology, which allows the asphalt to be produced at lower temperatures than conventional hot-mix asphalt. The company says this reduces embodied carbon during production.The idea also fits into a broader push to make road construction more circular, instead of treating used tyres solely as a disposal problem, part of their material can be recovered and incorporated into new infrastructure.The M1 trial therefore represented more than an experiment in changing what roads are made from. It tested whether one of Britain’s largest waste streams could be given a second life beneath the wheels of the vehicles generating the demand for new roads in the first place.