A20 Resurfaced with Kent’s Highest-Ever Recycled Asphalt Content

A section of the A20 in central Maidstone has been resurfaced using a lower-carbon asphalt containing 60% recycled content — the highest proportion used on a Kent highway scheme to date.

The material was developed by Heidelberg Materials UK in collaboration with contractor GW Highways, supporting both companies’ carbon reduction targets and Kent County Council’s wider ambition to embed circular economy principles in highways maintenance.

To deliver the scheme, the team secured a departure from standard specification to allow 60% reclaimed asphalt to be incorporated into the binder course. This reduced reliance on primary aggregates while promoting material reuse.

Addressing Kent’s Aggregate Challenge

Kent’s geology means the county lacks suitable aggregates for asphalt production, requiring material to be imported by road, rail or sea. This increases embodied carbon and exposes supply chains to market volatility.

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By maximising the use of locally sourced recycled materials, the scheme reduced demand for virgin aggregates, improved security of supply and cut transport-related emissions.

For the 20mm binder course, laid at 60mm thickness, a specialist additive was used to soften the residual bitumen within the reclaimed asphalt. This enabled higher recycled content while maintaining durability and improving workability.

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The asphalt was produced at Heidelberg Materials’ Allington plant and laid during night-time closures to minimise disruption to traffic.

Paul O’Neill, Regional Asphalt Director at Heidelberg Materials UK, said:

“This project is the first time we have supplied asphalt with 60 per cent recycled content.”

Byron Lovell, Pavement Asset Engineering Manager at Kent County Council, added:

“Reducing our reliance on primary aggregates is essential for both carbon reduction and long-term resilience in Kent. This project demonstrates how working closely with our partners can deliver real progress towards more sustainable highways. It is an encouraging milestone as we look to trial the use of recycled materials across future schemes.”

The project is expected to inform further trials of high-recycled-content asphalt across the county’s road network.