Tarmac pioneers recycled surfacing on the national network via M25
A Tarmac and Mouchel Parkman joint initiative on behalf of the Highways Agency has pioneered a new recycled road surface on the national network.
The material has been used as part of a resurfacing project which, for the first time on the national highway network, has seen nearly 800 tonnes of existing porous surface course material recycled into the new road surface – setting the standard for recycling on future major schemes.
It is highly unusual to reuse existing material, usually of unknown origin and lower quality, in thin and high quality surface asphalts – which need to offer high Polished Stone Values (PSVs) for good skidding resistance.
After Tarmac, and Tarmac-owned planning company NRP, removed some 270 tonnes of existing surfacing per night for 12 nights, it was taken in lorries for special processing at Tarmac’s Hayes asphalt plant including screening to remove oversized aggregate.
Each batch of recycled material was then re-laid on the next night – forming a quarter of the 3,255 tonnes of new 14mm aggregate ‘Tarmac MasterPave’ surfacing over 30,000 square metres laid at junctions seven on the M25. The remaining existing material was routinely recycled by Tarmac for use in base and ‘bindercourse’ materials.
Further benefits are gained as this process improves the efficiency of the lorries, which would have otherwise returned to the plant empty after delivering asphalt to site.
Tim Smith, Tarmac’s technical manager London & South East said: “Working towards a sustainable future requires innovation in process and creativity in thinking.
“After extensive lab tests and practical trials we demonstrated that the new surface would meet the high performance standards needed – for PSV, texture depth, deformation resistance and durability. The innovative approach has enabled us to cut the volume of virgin material required for the resurfacing work and put the existing material to best possible use.”
Steve Smith, project manager for Mouchel Parkman M25 Sphere Small Works Team said: “I am delighted that we have been able to work closely with Tarmac in developing a strategy for dealing with materials that would otherwise go to waste. These could be the first steps in changing the way we approach the renewal of the Highways Agency’s road network.”
Tarmac is working in conjunction with Mouchel Parkman, the Highways Agency’s Managing Agent (M25 Sphere), and main contractor Carillion. Mouchel Parkman has commissioned the Transport Research Laboratory (TRL) to report on the environmental and financial benefits of the approach, with the TRL’s report due in early October.
The innovative approach was approved and supported by the Highways Agency, following an application by Mouchel Parkman for a ‘departure from standards’ as the specification allowed a maximum 10 per cent of recycled material in the surface course.
15 October 2007
See more on the Tarmac Recycling website
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