The UK is ready for rubber – Tarmac’s new asphalt solution

A huge surplus of waste tyres and a strengthening commitment towards sustainability from local authorities has prompted asphalt supplier Tarmac to invest in technology to add crumb rubber to its mixes "Local authorities want to be green, sustainable and environmentally friendly,” said Tarmac’s technical director Brian Kent. “I get the sense that these issues are more important to them now. I do think we are going to get some traction.” Around 40 million tyres are worn out every year in the UK. Though
September 6, 2019 Read time: 3 mins
Tarmac is now using crumb rubber in asphalt
A huge surplus of waste tyres and a strengthening commitment towards sustainability from local authorities has prompted asphalt supplier Tarmac to invest in technology to add crumb rubber to its mixes


"Local authorities want to be green, sustainable and environmentally friendly,” said 2399 Tarmac’s technical director Brian Kent. “I get the sense that these issues are more important to them now. I do think we are going to get some traction.”

Around 40 million tyres are worn out every year in the UK. Though some are burnt for fuel at cement kilns, others turned to crumb rubber and used for sports pitches and to create items like car mats, there is still a surplus of 120,000tonnes of rubber waste. Currently these are shipped abroad.

Tarmac has modified seven of its 72 asphalt plants so that 1% of crumb rubber by weight can be added to mixes. This is combined with a warm-mix additive, Evotherm, so that the harmful emissions are not produced during the manufacturing process. Tarmac reckons this equates to 750 waste tyres/km of road resurfaced.

The company started investigating the use of end-of-life tyres (ELT) in asphalt back in 2011. They chose a method has been used successfully in the US for over a decade, said Kent.

This process is somewhere between the wet and dry processes for adding rubber to asphalt mixes. The rubber become part of the asphalt matrix, melting at first and then resolidifying to act “like a glue”, said Kent.

The result is a mix that is better than one created with standard bitumen, but not as enhanced as one made with a polymer-modified bitumen. Kent did not provide any test results to demonstrate its performance, saying that there were no tests that adequately mimicked ageing.

“Talking to colleagues in America, they have come to the conclusion that because rubber is in the material, it is helping to delay crack propagation and that means the roads are lasting longer,” said Kent. He added that where rubber is used in SMA (stone mastic asphalt) mixes, the crumbs sit in some of the air voids, improving waterproofing and hence enhancing durability.

The first UK authority to trial the mix was Coventry, with national authority Highways England also carrying out a trial on the M1 motorway near the East Midlands Airport. Authorities in London, Nottingham and Leicester are also planning trials with several others expressing interest.

Modifications to the asphalt plants involve adding an automated system to the plant which includes a silo, a screw to mix and making modifications to the software. The cost for modifications varies, depending on the plant but costs tens of thousands of pounds. Other plants will be upgraded, depending on market demand, says Kent.

Materials

For more information on companies in this article

Related Content

  • Micro surfacing the Brooklyn Bridge with Bergkamps’ M210 paver
    May 16, 2018
    A major job for micro surfacing took place on the Brooklyn Bridge near New York. It was the third time in Ken Messina’s career that he would provide micro surfacing for the iconic Brooklyn Bridge, built in 1883. Messina, as president of New Jersey-based Asphalt Paving Systems (APS), knew only too well the challenges that lay ahead. And there were many. There would be only a brief window of opportunity for paving, with lane closures starting at 10pm and ending at 5am. The cool, humid atmosphere would a
    Read More
  • Bitumen balance in RAP
    November 29, 2012
    *Bitumen from recycled asphalt can be rejuvenated using additives, according to Iterchimica The use of reclaimed asphalt pavement (RAP) is common in many countries. However, the aged bitumen from RAP has a lower penetration and is more viscous than when first mixed. This reclaimed bitumen is generally balanced by the addition of fresh binder that is softer than those typically used to produce hot mixes. But balancing penetration and softening point or viscosity will not deliver bitumen identical to the orig
    Read More
  • The drive for US road funding: will corporate America get a seat?
    September 13, 2017
    Trumponomics aims to use public money for pump-priming an even greater amount of cash from the private sector to improve America’s crumbling roads. But is political will matching corporate America’s enthusiasm for more private investment, asks David Arminas If there were ever a test case for comparing public-private partnerships and design-build contracts, the recently completed Ohio River Bridges Project is it (see previous article).
    Read More
  • Eurobitume Preview 2012
    June 15, 2012
    Asphalt and bitumen industry attention is turning to the Eurasphalt and Eurobitume (E&E) Congress Congress being held next month in Istanbul, Turkey. Guy Woodford reports Held every four years, the Eurasphalt and Eurobitume Congress is always a well-attended event that can be both commercially beneficial and thought-provoking for asphalt and bitumen industry companies and organisations. Judging by a joint statement released by Eurobitume president Alberto Bardesi and European Asphalt Pavement Associatio
    Read More

Highlighted Content