Highways England accelerates move to lower-carbon asphalt

Image: Highways England

Highways England is to encourage contractors to switch to lower-carbon warm mix asphalts (WMAs) more quickly, in a drive to save 61,000 tonnes of carbon a year.

Highways England has been using WMAs since 2015. While typical asphalts are produced at up to 190oC, WMAs are kept at temperatures up to 40oC lower with additional additives, creating a CO2 saving of up to 15%.

If all production in the UK switched to WMAs, around 61,000 tonnes of CO2 a year would be saved. £70m a year could also be saved through an increase in shift outputs because WMAs take less time to cool, allowing greater volumes of asphalt to be laid. WMAs can be laid using existing equipment and can be recycled back into new asphalts.

Highways England said another benefit of WMAs is improved health and safety, not only due to a reduction in the risk of burns but also because fume generation is around 50% lower for each 10°C reduction in temperature.

According to an All-Party Parliamentary Group on Highways’ report in September 2019, WMAs account for almost 40% of asphalt production in the US and more than 15% in France. But in the UK they represent less than 4% of overall asphalt production. At Highways England, WMAs previously required an application from the supply chain for a departure from standard. The change in policy will now make that process easier.

Malcolm Dare, executive director of commercial and procurement at Highways England, said: “This is a big step forward for Highways England that allows us to not only achieve huge efficiency savings but also reduce carbon as we strive for net zero.

“Carbon reduction, along with ensuring our roads provide smooth, safe, and efficient journeys for motorists, are key and something we are constantly striving to improve for generations to come.

“That’s why we are altering our way of working to encourage and enable the use of warm mix asphalts as standard across the supply chain, which has efficiency, sustainability, and health and safety benefits whilst not compromising performance.”

Paul Gott, project sponsor from Morgan Sindall Infrastructure, said: “We are delighted that we’ve formed a group from across the supply chain who are focused on embedding carbon reduction measures across Highways England’s schemes.

“Warm mix asphalt is the first carbon efficiency project on the group’s extensive carbon reduction plan, which is evolving and already identifies several short-, medium- and longer-term goals.”

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