The Compactasphalt system from Atlas Copco subsidiary Dynapac uses two screeds, synchronised to provide a high compaction screed with a standard wearing course. Because both courses remain hot, a better inter-lock can be achieved and less material needs to be used in the wearing course.
While conventional aspalting needs a 40 mm wearing course on an 80 mm binder layer, the new method only requires a 20 to 25 mm wearing course.
Claes Ahrengart, road division chief at Atlas, said: “It is more like welding the layers than the conventional glueing.”
He said there are a range of further benefits to the system, which has been approved by the German road authorities but not yet by the Highways and Utilities Committee in the UK.
“You are combining two operations, so there are reductions in time and material,” Mr Ahrengard said.
“In addition the road life is extended, there is high deformation resistance and lower maintenance costs.”
The current machine system, comprising a paver with two screeds fed by a tracked feeding system, is designed for road widths from 3 m to 12 m. The two layers are supplied from hoppers, one on top of the paver and the other behind it, offering 25 tonne and 45 tonne capacity respectively.