Tarmac recycles complete job

In the first venture of its kind on the national highway network, Tarmac has recycled all the materials removed in an M25 resurfacing project into the new road.

Nearly 800t of porous asphalt was removed and processed at its asphalt plant in Hayes, Middlesex, to remove oversized aggregate before being added to the new surface course.

Almost 25% of the new surface was made up of the recycled material, while all remaining arisings were used for the base and bindercourse.

It is unusual to reuse existing material in thin and high quality surface asphalts as they need to offer high Polished Stone Values (PSV) for good skid resistance.

Tim Smith, Tarmac's technical manager for London and the South East, said: "Mouchel Parkman is interested in innovation and asked us how to best recycle the arisings. As the surface was made up of porous asphalt, which is of a high quality, it was possible to recycle it into the surface course.

"This is rare, particularly in applications like this, as the aggregate is subject to such high levels of stress."