Amey Consulting says that it has designed the UK’s first carbon-neutral road improvement project – a Highways England carriageway resurfacing project in county Cumbria, northern England.
Amey Consulting’s carbon modelling experts worked with the client Highways England agency and contractors including Aggregate Industries and A E Yates and traffic management firm HW Martin.
The £8 million (€9 million/US$11 million) project was for a section of the A590 and resulted in significant reduction and increased use of on-site materials, lower energy use and more efficient transportation planning. Carbon was reduced by up to 43% compared to traditional solutions and saved almost £3m, according to Amey, a major contractor for Highways England maintenance projects.
Early collaboration between Amey Consulting, Highways England and contractors was key in developing the low-carbon solution as well as a carbon model designed specifically for the project. It was used to calculate carbon emissions saved during the construction stage.
The model allowed for comparison of carbon reduction measures against a baseline traditional solution. Key initiatives which reduced emissions during the construction stage included the ex-situ (off-site) foam-mix recycling of existing road surface planings, by producing a site-batched cold recycled asphalt.
This significantly reduced the need to import and export materials to and from the site. It also erased around 6,000 heavy truck movements, saving 230 tonnes of CO₂-eq (CO₂ equivalent, a metric measure used to compare emissions from various greenhouse gases on the basis of their global-warming potential).
The shortened construction programme also reduced road diversions and traffic management impacts on the local community. Importantly, the recycled road surface has greater porosity compared with a hot-rolled asphalt or concrete, helping to reduce rolling noise from vehicles.
In addition to the carbon benefits associated with the pavement solution, significant carbon reductions were also realised as a result of energy efficiency measures. The use of solar powered generators, lighting, signage, CCTV and catering facilities, along with the use of electric vehicles saved about 70 tonnes of CO₂-eq.
“The safety of road users was our key concern in the planning of this project,” said Steve Mason, senior project manager with Highways England.
“The installation of an ex-situ recycling option and on-site asphalt plant gave us the opportunity to work 24/7, removing the need for many thousands of deliveries but also allowing us to complete work near the motorway junction as quickly as possible and reduce queuing associated with the roadworks.
Alex Gilbert, managing director of Amey Consulting said he believes that the carbon-neutral strategy used on A590 project has the potential to be replicated across the UK.
Amey, the parent company of Amey Consulting, is owned by Spanish infrastructure group Ferrovial.