Tarmac and National Highways deliver ground-breaking carbon savings in strategic road network resurfacing trial
A CUTTING-edge trial on the A64 has delivered what is said to be the UK’s lowest carbon resurfacing scheme on the strategic road network without using carbon offsetting.
Tarmac and National Highways, together with supply chain partners, successfully reduced carbon emissions on the project by 75% compared with 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 and 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% 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, minimizing 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.
Eliminating joins reduces water infiltration into the road surface, resulting 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.
Enhanced pavement life and a high-performance, smooth pavement was achieved through continuous paving using an ‘echelon’ paving method
In addition, to assist with the ultimate drive to net-zero pavements, a small 150m section utilizing 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 decarbonizing every element of highways maintenance. It demonstrates how shorter, more focused use of road networks can improve efficiency, boost productivity, and minimize night-time 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 decarbonization.
Angela Halliwell, head of carbon and environmental sustainability strategy and planning at National Highways, said: ‘We’re taking positive steps towards a more sustainable, decarbonized 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 decarbonize 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.’
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