Pioneering recycled road surface on national network
A Tarmac and Mouchel 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 road surface course material recycled into the new road surface.
The reuse of existing material in thin and high-quality surface asphalts, which need to offer a high PSV for good skid resistance, is highly unusual as it is usually of unknown origin and lower quality. However, after Northampton-based Tripod Crest Planing removed some 270 tonnes of existing surfacing each night for 12 nights, it was taken to Tarmac’s Hayes asphalt plant for special processing, including screening to remove oversized aggregate.
Each batch of recycled material was then re-laid the following night, forming 25% of the 3,255 tonnes of new 14mm aggregate ‘MasterPave’ surfacing covering 30,000m2 at Junction 7 on the M25. The remaining existing material was routinely recycled by Tarmac for use in basecourse and binder-course materials.
‘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,’ explained Tim Smith, Tarmac’s technical manager London & South East. ‘This innovative approach has allowed 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’s M25 Sphere Small Works Team, added: ‘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.’
The innovative approach was approved and supported by the Highways Agency, following an application by Mouchel for a ‘departure from standards’, as the original specification allowed a maximum 10% of recycled material in the surface course.
The reuse of existing material in thin and high-quality surface asphalts, which need to offer a high PSV for good skid resistance, is highly unusual as it is usually of unknown origin and lower quality. However, after Northampton-based Tripod Crest Planing removed some 270 tonnes of existing surfacing each night for 12 nights, it was taken to Tarmac’s Hayes asphalt plant for special processing, including screening to remove oversized aggregate.
Each batch of recycled material was then re-laid the following night, forming 25% of the 3,255 tonnes of new 14mm aggregate ‘MasterPave’ surfacing covering 30,000m2 at Junction 7 on the M25. The remaining existing material was routinely recycled by Tarmac for use in basecourse and binder-course materials.
‘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,’ explained Tim Smith, Tarmac’s technical manager London & South East. ‘This innovative approach has allowed 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’s M25 Sphere Small Works Team, added: ‘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.’
The innovative approach was approved and supported by the Highways Agency, following an application by Mouchel for a ‘departure from standards’, as the original specification allowed a maximum 10% of recycled material in the surface course.
