Fast track paving from Volvo Construction Equipment
The Balocco track was built in the 1960s by Alfa Romeo before it was acquired by the Fiat Group. Each year around 20,000 vehicles including new cars, prototypes and racing cars, are put through their paces on the course’s test tracks.
One circuit has recently been re-paved – the 7.8km (4.8 mile) high-speed track, with three driving lanes, each 4m wide, plus an emergency lane which is 2.5m (8ft) wide. This is a torturous road course of 65km (39 miles), modelled on some of the world’s most famous racing tracks. The slope of the track’s curves range from 2% to 27% and speeds can reach up to 280km/h (174 miles/h).
Mauro Martelli, head of the new Road Machinery Division of Volvo Construction Equipment, and Mauro Arletti of Arletti Pavimentazioni Stradali were responsible for the project, which involved the delicate application of layers of bituminous mixture – binder and wear – on both the straight sections of track and a series of curves. Their solution was to develop a unique spreading method using a customized screed able to perfectly fit the shape of the circuit surface.
Mauro Martelli commented: ‘The possibility of performing a spreading operation on a perfectly concave base without interruption and to vary the settings according to the surface profile is a new process. The market has made solutions available for the so-called cambered road spreading in various alternatives, but no solution of this kind.’
The new paving – separated from the base by a SAMI waterproof membrane, made using modified bitumen emulsion – consists of a binder and a wear course. This was made using a special high-performance bitumen for racing circuits provided by Valli Zabban and CoBit.
In order to make the joints invisible, two Volvo ABG 8820 tracked pavers with modified screed worked in parallel and were supported by a wheeled paver, the Volvo ABG 6870, to lay the mixture. The screed, fitted to the two pavers, was produced according to specifications provided by Arletti and Volvo Construction Equipment Italia.
‘The main technical problem we had to solve was to shape the convex curves of the race track when the path straightens,’ said Martelli. ‘Because of the peculiar characteristics of this circuit, we had to repeat this operation six times with three different modalities and two different radii at the entrance and at the exit of the curve.’
