Skanska and Tarmac are trialling a new carbon-negative aggregate on a stretch of motorway as part of National Highway’s aim to reduce its carbon footprint.
The trial is taking place on the northbound carriageway of the M11 in Essex and has been incorporated into essential resurfacing and maintenance work between junctions 7 and 8.
It will be subject to real conditions on the heavily trafficked motorway and will be routinely monitored by National Highways.
A test strip of asphalt concrete binder course containing the product has been laid alongside a control test strip containing 100% conventional aggregate.
National Highways hopes the carbon-negative aggregate will reduce its carbon emissions with minimal change to standard procedures.
Towards net zero maintenance and construction
The “next generation” material was identified in the Accelerating Low Carbon Innovation competition run by National Highways. This offered funding for projects that would help meet targets for net-zero carbon in maintenance and construction.
It was “thoroughly tested” for eight months against Highway Specifications and successfully trialled on the National Highways strategic road network.
Four companies received up to £80,000 each towards their projects. The first of these – Seaham-based Low Carbon Materials – has been able to trial its ACLA carbon-negative aggregate on a National Highways’ road for the first time.
Tim Smith, senior technical manager (South East) at Tarmac, said: “Fast-tracking this new material to a trial on the strategic network in record time as part of National Highway’s innovation programme represents another important example of how our industry can rapidly develop and trial innovations, getting them from the laboratory and out onto the road network.”
The other firms selected in the Accelerating Low Carbon Innovation programme which are continuing to develop their projects were:
- PRG (Scotland) Ltd, Hamilton: to produce a bitumen-like substance from waste tyres which would be useful for road construction and repairs.
- Circular11 Ltd, Christchurch, Dorset : to provide highly durable, maintenance-free fencing material that turns mixed low-grade plastic into low-carbon infrastructure, and which will be collected and recycled at end-of-life.
- Asset International Structures, Cwmbran: to develop smart fibre-reinforced polymer bridge beams that incorporate a novel optical fibre, enabling structural performance monitoring in real-time and over the long term.
