A racetrack project requires smoothness, and the National Corvette Museum Motorsports (NCM) Park was no exception. 3D paving technology reduced engineering costs and helped meet tight tolerances on this paving job.
The NCM Park, located in Bowling Green, Kentucky, is a test track for Corvettes, with the Corvette museum and a General Motors factory less than a mile away. Project specifications prohibited deviations of more than 3 mm (1/8 in.) around the track and a smooth joint in the center of the course surface.
“There could not be a cold longitudinal joint,” says Chris Higgins, engineering manager at Scotty’s Contracting & Stone. That meant two pavers worked in echelon, and the joint was compacted while still hot. “It’s really like there isn’t a joint.”
Also required on the job were material transfer vehicles—in this case Weiler E2850s. The MTVs deliver hot mix without making contact with the pavers, while allowing the pavers to work continuously at a consistent speed.
“The final day of surfacing on the track consisted of 13 hours of nonstop paving with pavers side by side to eliminate the joint in the track,” says Kenny Reynolds, paving manager at Scotty’s. “The transfer machines and pavers were refueled while they were all moving to eliminate the need for stopping.”
Cat® AP1055D and AP1055E Asphalt Pavers laid down the mix. Four Cat CB64 Vibratory Asphalt Compactors handled breakdown, intermediate and finish phases of compaction, achieving 92 percent to 93 percent density.
3D paving technology played a huge part in preparation and paving of the track.
“During rough grading, the 3D AccuGrade™ dozers worked to within tolerances of tenths of a foot,” says JD Weis, general sales manager with SITECH™ Mid-South, which specializes in the sale of Trimble® products. “Then machines equipped with 3D Total Station based Cat AccuGrade systems were used to complete the more accurate grading, down to hundredths of a foot. Now we’re coming back with the 3D paving systems and getting the tolerances down to thousandths of a foot.”
One of the most impressive benefits of the 3D paving system was its ability to use slope control on the joint match side of the trailing paver screed and have consistent height match. This accomplishment underscores the speed, accuracy and inter-connectivity of the Trimble system.
Higgins says the technology, at all steps of the process, enabled enormous productivity gains. “We never would have finished on time without it. The biggest benefit of 3D paving is it precisely and accurately achieves the design, giving us the smoothest, most consistent surface possible.”