The UK’s National Highways has revealed that a sustainable highway construction trial is being conducted by infrastructure and construction company Kier and TerrAffix on the A417 Missing Link scheme in Gloucestershire, England.
Biochar, a charcoal-like substance created through pyrolysis, has been produced from vegetation cleared for the project, resulting in a carbon dioxide saving of 13 tonnes (t).
The trial has generated 5t of biochar on-site, which is now set to be integrated into various aspects of the A417 project.
This initiative recycles waste, turning it into a material that supports the construction process.
Specifically, the biochar is set to be used in landscaping to aid the growth of thousands of new trees, in the construction of a green bridge to retain water, and to capture microplastics from highway runoff.
National Highways and Kier, which is serving as main contractor for the A417 project, are co-funding this study, which is part of National Highways’ Environmental and Wellbeing Designated Fund.
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By GlobalDataNational Highways senior project manager Celine Acard said: “We’re always looking to improve how we design and build our major projects, especially in relation to the environment and our commitment to net zero.
“This trial is incredibly exciting because it means we can look in detail at new ways or repurposing and reusing site materials to cut down on our environmental impact.
“By investing in innovation, we can explore new technology and solutions to protect and enhance the environment and increase biodiversity benefitting communities that live alongside our roads.”
The trial aims to demonstrate the benefits of biochar in enhancing plant growth, soil nutrient exchange, and water retention, thereby improving habitat establishment and offering climate change resilience.
Meanwhile, the use of pyrolysis for on-site carbon capture signifies a pioneering step in construction, aiming to reduce carbon emissions, vehicle movements, and the purchase of materials.
Upon completion, the project is expected to serve as a proof of concept, potentially allowing for the wider deployment of this technology across suitable highway schemes.
National Highways has invested close to £936m ($1.35bn) up to 2025 via its designated funding programme, allocated to four key areas: safety and congestion, innovation and modernisation, users and communities, and environment and well-being.
