Vögele: Strong together for Formula 1 race track rehabilitation

Wirtgen Group machines produce a new surface course on the Circuit de Spa-Francorchamps.

The challenging Spa-Francorchamps race track in Belgium was rehabilitated with the aim of enhancing its attractiveness to spectators and, above all, of improving the safety of racing drivers. 

The Circuit de Spa-Francorchamps construction project posed particular challenges to all involved, as the track was not a design fresh from the drawing board, as is usually the case, but has been in existence for over 100 years and includes ordinary roads. CEO Jarno Zaffelli, whose company Dromo Circuit Design delivered the project, emphasizes how very demanding this rehabilitation task is - due in particular to the undulating nature of the circuit. There are extreme sections featuring gradients of 20%, such as the legendary combination of the Eau Rouge and Raidillon corners. A further challenge was presented by the hairpin bend La Source (“the spring”), because spring water gets onto the track here. To ensure maximum driver safety on the tough Circuit de Spa-Francorchamps, extremely stringent conditions in terms of evenness and grip were applied to the asphalt surface course.

Belgian company Bodarwé was contracted to complete the asphalt paving . The variations in level around the winding race track present a challenge to the paving team, as well as to racing drivers. “For years, we have been working with contractors who use Wirtgen Group machinery. We know the machines very well, and are familiar with what they deliver in terms of quality and reliability,” explains Zaffelli.

The project was to pave a new surface course on a section extending to 505 m from the Eau Rouge valley up to the famous sweeping Formula 1 corner at Raidillon. Another 206 m section was to be paved in the area of the T9Car Formula 1 corner to the north, as well as 701 m for the new T8Moto and T9Moto motorcycle race corners. The requirements below were imposed on the paving team to ensure the optimum quality of the track sections. Paving had to proceed non-stop, at a rate of between 3 and 4 m per minute. The temperature of the asphalt material was set at 180 °C in order to maintain a sufficiently large compaction window even at the low outdoor temperatures prevailing at the time. A further requirement was for the temperature of the paved surface course to be monitored and documented continuously.

The composition of the material plays a key role in the quality of a Formula 1 track surface. The formula, in this case code-named "Le Noir", was developed by Dromo especially for Spa-Francorchamps in accordance with the regulations of the Fédération Internationale de l'Automobile (FIA). It is a well-kept secret. The material was mixed in the asphalt mixing plant belonging to Bordarwé subsidiary Boreta S.A. The Benninghoven TBA 4000 plant is characterised by the highest quality and production standards, as well as by a wide range of options.

Once the surface course in the relevant sections had been removed by a Wirtgen W 220i cold milling machine complete with LEVEL PRO ACTIVE milling depth regulator and 3D controller, three Vögele SUPER 1800-3i machines were deployed. The task was to pave three 4.1–4.3 m strips without joints using the tried-and-tested hot-to-hot method. The three pavers were each equipped with an AB 500 TV Extending Screed and a Big MultiPlex Ski to ensure maximum longitudinal evenness. Three multi-cell sonic sensors were fitted to the variable carriers of the Big MultiPlex Ski, each scanning the binder course/the adjacent surface course and ensuring precision paving.

The three pavers were equipped with WITOS Paving Docu incorporating the RoadScan temperature measurement system to monitor and record paving temperature. The system recorded not only asphalt temperature, but also the other paving parameters: geometry, surface area, distance and volumes of asphalt paved. Bodarwé’s construction manager Sébastien Dandrifosse was very pleased: “WITOS Paving Docu is ideal for monitoring temperature directly on-site; this is where we need the information, so that we can counteract any deviation immediately.”

Machines and people worked together to the highest standards on the legendary race track in Belgium’s Ardennes mountains. The demands of the project were intense, but operators used the machinery and technology to overcome every challenge they faced. The race track design team were also impressed by the support provided by the Wirtgen Group, as Jarno Zaffelli sums up: "The backup from their technical team was very good - and extremely important. It is very reassuring to have experts like that by your side when running a paving operation that can’t easily be repeated.”