A trial on the A64 is being hailed as delivering the UK’s lowest carbon resurfacing scheme on the strategic road network without using carbon offsetting.
Tarmac, a CRH Company, and National Highways, together with supply chain partners, successfully reduced carbon emissions on the project by 75% compared to a traditional maintenance project of a similar scale, with over 260 tonnes of carbon savings delivered.
The trial – the first of its kind on the strategic network – was delivered on a 1.5 mile section of the A64 eastbound carriageway at junction 44 near Bramham in North Yorkshire.
Over a seven-day period the team, including HW Martin, Premier Roadmarkings, Kier and Mway Comms, combined an extensive range of innovative low carbon materials, use of innovative paving technology and plant equipment to deliver the significant carbon savings.
Overall, 41.3% of the project’s carbon reduction total was delivered using low carbon raw materials, 14.7% from the transport of materials and the paving process, including the use of electric plant equipment, and 44% from employing sustainable manufacturing techniques.
A warm mix asphalt was used together with a pioneering ‘carbon sink’ bio-component binder from Shell, which locks carbon into the road to prevent it being released into the atmosphere. The lower layer of the pavement used 40% recycled asphalt planings (RAP) with a further 20 per cent in the surface course to help reduce the need for primary materials.
A number of zero emissions plant vehicles and prototypes were used including electric and hybrid road rollers and an electric bond coat sprayer, minimising noise and further reducing tailpipe emissions as well as CO2. Tarmac’s Cross Green asphalt plant in Leeds, which manufactured many of the materials used on the project, was powered by a combination of biofuel and clean electricity.
Other construction methods adopted on the scheme delivered significant benefits including enhanced pavement life and a high performance, smooth pavement. This was achieved through continuous paving using an ‘echelon’ paving method, where asphalt is laid across the entire road surface, rather than in lanes.
Tarmac explains that eliminating joins reduces water infiltration into the road surface. This results in a more durable road that is expected to last more than 20% longer than those constructed with conventional surfacing methods. It also requires less maintenance, reducing operational carbon in the longer term. In addition, the increased smoothness of the surface improves ride quality which reduces fuel consumption, therefore lowering associated emissions and particulates from vehicles.
In addition, to assist with ultimate drive to net zero pavements a small 150m section utilising all of the above technologies but this time with a standard penetration grade binder and a small percentage of a negative carbon aggregate facilitated the landmark achievement of the UK’s first net zero pavement.
Brian Kent, National Technical Director at Tarmac, said: “This trial sets a blueprint for low carbon delivery on the strategic road network and the exacting requirements of decarbonising every element of highways maintenance. It demonstrates how shorter, more focused use of road networks can improve efficiency, boost productivity and minimise nighttime closures, reducing disruption for road users.
“The ambitions of this scheme reflect our commitment to delivering not only low carbon pavements but also the significant benefits of new delivery models which will be essential as part of the transition to net zero.”
The sharing of vital learnings and expertise from this project will help the supply chain collectively adopt new approaches and tackle the sector-wide challenge of decarbonisation.
Angela Halliwell, Head of Carbon and Environmental Sustainability Strategy and Planning, National Highways, said: “We’re taking positive steps towards a more sustainable, decarbonised future. We hope this project will pave the way for industry-wide changes, resulting in significant carbon savings and improved road surfaces for drivers.
“National Highways has ambitious plans, backed by science, to decarbonise the road network. We aim to achieve net zero for our corporate emissions by 2030, for our maintenance and construction activities by 2040, and for our whole network by 2050.
“A net zero Britain will still travel by road, and finding low carbon ways to maintain our road network is vital. National Highways’ carbon management system and low carbon opportunities register capture innovations like those used on this project, with the intention to make them standard procedure across the road network in future.”
(Picture – Tarmac)
