New “recycled road” surface trial paves way to zero carbon highways
A project to resurface a stretch of road in East Anglia – using recycled materials and electric machinery – is smashing low carbon targets.
National Highways tasked its contractors Heidelberg Materials and WSP to deliver resurfacing of the A47 between Acle and Great Yarmouth, in a low carbon way.
The result is a new structural layer of the road that's made from more than 90 per cent recycled materials. Typically, pavement layers use much less recycled or reclaimed asphalt content.
With a recycling plant close to site, the project is predicted to save 400 tonnes of CO2 on what would previously have been used. This is the equivalent to powering 142 average households for a year.
National Highways, which resurfaces over 1,200 lane miles each year, says many factors were involved in creating a new low carbon road service.
Alice Grandidge, Project manager for the scheme at National Highways, said: “We know that good quality roads are important to the millions of drivers that use our network each day. This scheme presented the ideal opportunity to resurface a road effectively but in a low carbon way - from the materials we use, where we sourced it from, how we mixed it and when we work on it. All these aspects combined together save carbon compared to a traditional approach to a road resurfacing scheme – it makes it one of the greenest major road resurfacing and is a major step towards carbon zero highways.”
Scott Cooper, Managing Director of Contracting at Heidelberg Materials UK, said: “This scheme is a great example of the effectiveness of supply chain collaboration in driving carbon reduction measures.
“The change in design specification to use evoBuild foamed asphalt resulted in a dramatic increase in recycled content and provided substantial savings in CO₂ emissions compared with using hot mix asphalt as its production requires significantly less energy.
"The addition of the extensive use of electrified plant demonstrated what the future of road laying could look like. The project is an excellent example of sustainable highway construction in practice.”
Dermott Doyle, Technical Director at WSP commented: "Delivering infrastructure that balances operational excellence with low carbon impact is a key priority for WSP. On the A47 project, we worked closely with National Highways and Heidelberg Materials to design a major pavement intervention that maximises recycled content and reduces carbon emissions, demonstrating how sustainable practices can be integrated into everyday road construction."
A “Cold Recycling Bound Material” was used on the site - this is a sustainable paving material made from recycling existing road materials, such as asphalt and concrete. The process takes the "old" material, crushes it into aggregate, injects with air and water, and then produces a new foamed bitumen. The result is a sustainable, durable, weather resistant material, offering an environmentally friendly alternative to traditional road construction materials.
The material in the original design, for example for the A47, would have had a recycled content no greater than 10%.
Additionally, a low-carbon recycling plant was used close to the A47 road so that helped save carbon due to the short distance from the plant to where the road is being resurfaced. Electrified plant machinery, such as pavers and rollers were used, along with low carbon transport such as hydrogen low loaders.
Ms Grandidge added that this demonstration could be replicated on other roads but not all.
She said: “Road surface types are determined by traffic usage so such a surface would potentially not be suitable on a more busy road such as the A1.
“However, many lessons can be learnt from this that can be replicated in some other areas across the country. It is an example of how we need to adapt to meet carbon zero targets and work in a greener way.”
Key stats:
- Projected carbon saving exceeding 400 tonnes of CO₂:
- Increasing the use of recycled materials by more than 137,0500 tonnes.
- Providing a textbook example of the circular economy in practice each shift.
- Recycling 2,400 tonnes of tar-bound material, preventing its disposal in specialist landfill sites.
- Eliminating the need for virgin aggregate in large volumes, especially critical in a region with limited local geological availability.
- Cold Mix Recycling plant situated close to site (8 miles away) reducing transport distances and associated carbon. (16 miles closer than asphalt supply plant)
Work started on the road in May and ends this month. All work is being carried out overnight.
Notes to Editors
Additional notes
-This year, National Highways has established a Low Carbon Demonstrator Fund to help successfully trialled products take the next step towards becoming a standard option for resurfacing schemes
The fund is enabling projects across the country to take opportunities with the new low carbon technologies and helping suppliers to make a sustainable transition toward using them as a new business as usual
- The A47 Acle Straight was selected as a carbon exemplar project because it is located in a region where suitable aggregates are scarce and not readily available for asphalt production. Using traditional construction methods would have required importing large quantities of aggregate from distant sources, resulting in significant carbon emissions and increased heavy vehicle movements.
-By selecting this scheme as a carbon exemplar, a mobile recycling plant was brought close to the site, drastically reducing transport requirements. The project placed a strong focus on maximising the use of recycled materials, minimising the need for new virgin aggregates, and therefore reducing the overall carbon footprint.
-In addition, the A47 Acle Straight scheme provided an excellent opportunity to demonstrate the effectiveness of CRBM (evoBuild Foamed Asphalt). This process allows for the recycled layer to be overlaid with a surface course and reopened to traffic within a single night shift, showcasing both environmental and operational efficiency.
-National Highways is the wholly government-owned company responsible for modernising, maintaining and operating England’s motorways and major A roads.
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