Vogele pavers rehabilitate the vehicle dynamic assessment pad of Continental Tire the Americas LLC in the USA.

A Super 2100-2 replaced the asphalt pavement of the Vehicle Dynamic Assessment Pad (VDA Pad) at the Conti Proving Grounds in Uvalde, Texas (USA). To ensure totally reliable results in tyre tests, the evenness of the pavement had to meet extremely exacting standards. Selecting a high compaction screed for the paving work helped produce a top-quality pavement.

Selected drivers can really put their foot down on the pedal in Uvalde, Texas. A little over 110 km from the Mexican border, this is the home of the Uvalde Proving Grounds of tyre manufacturer Continental Tire the Americas, LLC. Conti's 2,023-hectare site includes 11 different courses for testing its tyres in the toughest conditions: a high-speed oval, various asphalt, cement, gravel and mud courses, rocky terrain and numerous special test courses. The climate is ideal for testing purposes, with mild to warm temperatures prevailing year-round in the region.

Conti prefers to produce its own bad weather - to be precise, the tyre manufacturer uses, among other things, its Vehicle Dynamic Assessment Pad measuring 60,000 sq m whose asphalt pavement has now been rehabilitated by a Super 2100-2. The pad has a one per cent slope and can be flooded with water to a depth between 1.3 and 2.8 mm. To yield useful findings on tyre behaviour in wet weather, however, the surface must be absolutely flawless and meet the highest standards as regards evenness and resistance to deformation, for the film of water must have a uniform depth over the entire area with no breaks.

Maximum pre-compaction

The existing pavement was first of all removed to a depth of about 12.5 cm. Once a spray seal had been applied, the Super 2100-2 with an AB 600-2 Extending Screed laid 4.5 cm binder course across a pave width of 4.5 m, followed by a wearing course, 2.5 cm thick, over the same width. To ensure that the mix could be compacted to the particularly high degree of 92-97 per cent demanded by Conti, the AB 600-2 came in the TP2 version with tamper and two pressure bars. Using high compaction technology with pressure bars driven by pulsed-flow hydraulics, the Vogele screed yields the highest degree of pre-compaction achievable by a paver. This, in turn, lays the basis for durable asphalt pavements resistant to deformation. In Uvalde, the pavement density was tested whenever 500 tonne of asphalt had been compacted, and met all the specified requirements.

Maximum evenness

For this job, evenness was another prime concern for Conti: a deviation of not more than 3 mm was permitted over a distance of 3 m, in both longitudinal and transverse directions. To meet with such stringent requirements, other factors, such as air temperature and the temperature of the mix, too, had to be taken into account. As to machine technology, contractor Reece Albert, Inc also opted for the highest precision, selecting Niveltronic Plus?, the Vogele system for automated grade and slope control. In order to monitor the paving process and ensure a perfect result, the paver was fitted with a Big MultiPlex Ski on the right-hand side to scan the base onto which to lay the asphalt. On the left-hand side, a US Ski scanned the already paved strip. In this way, the paving crew was able to ensure that even the slightest deviation from the exacting requirements was instantly detected and corrected.

The result was a tour de force in all respects. Chris Cornell, Business Development Officer at Reece Albert, Inc, was delighted with the German equipment, "The evenness we achieved with Vogele High Compaction Technology, in particular, was beyond anything we've achieved in the past." Thanks to this precision, Conti can once again count on highly accurate test results.