Talladega Paving Job Steeped With Angles
📅 Tue August 01, 2006 - Southeast Edition
It’s likely one of the steepest paving jobs in the country.
At 33 degrees — a 65 percent drop slope — the crew from Sunmount Corporation has had to come up with a new way of keeping the paving train where it needs to be as they resurface the track at Talladega Speedway in Alabama.
Work began May 2 to mill and repave the 2.66-mi. track and the 1,730-ft.-long pit road.
The slope on which they’re working is worlds away from the 2 to 6 percent drop slopes a contractor may encounter on a highway.
Project Manager John Hajdasz said neither trucks, pavers nor rollers can stay on a slope this steep, so they needed to come up with a way to ensure the proper grade is coming off the paver.
In previous racetrack paving jobs, Sunmount crews would support the machinery with equipment at the bottom of the track.
But Talladega’s unforgiving turns wouldn’t even allow that.
So for the first time, custom-made arms were attached to bulldozers at the top of the track to keep the pavers and rollers working.
Caterpillar D9s were mounted with an arm to support the Titan ABG paver and the grader. Cat D8s held up the rollers.
The support system is a result of years of design by Mechanical Supervisor Danny James. An arm is attached to the dozer to reach over the upper wall of the track. Off of that is a cabled winch system that goes through a series of pulleys to keep the paving equipment steady and parallel to the track.
It took a year of planning, design and fabrication work to get ready for the job to begin.
Hajdasz said it’s of the utmost importance to maintain the center of gravity on the paving equipment. Otherwise, one risks the chance of laying material that is top- or bottom-heavy.
“You have to be careful to make sure everything is set up properly where it’s not sliding or pushing or that type of thing,” he said.
If everything is set up perfectly, Hajdasz said it’s just like paving on a highway.
Well, not quite.
The asphalt mix, which has been used on other racetracks throughout the country, is “stiffer” than what’s normally used on a roadway. Hajdasz said the binder has a higher polymer content, which allows for a higher stability to withstand heat and lateral pressure.
“It’s a little gummy, but it goes on at about 350 degrees, which is the high end of any kind of asphalt mix,” he said. “As long as you roll it right away, you won’t have any issues. But you don’t have a lot of time to play with this. It needs to get rolled and put together as soon as possible.”
With the consistency of the material, as well as the fact that the paver is equipped with a tamping bar and a vibratory screed, there is no risk of the material slipping down the slope after it is placed, Hajdasz said.
“The roller doesn’t have to do a whole lot of work,” he added.
The track’s north and south turns are banked at 33 degrees, while the tri-oval at the grandstands is 18 degrees. It is 48-ft. wide with an additional 12-ft. truck lane and 12-ft. apron. In the first phase of the project, 5 to 7 in. of material was demolished in each of the turns. Crews used excavators on the steeper banks to complete this task and a Wirtgen cold mill on the tri-oval and the straightaways.
For the 18-degree banks, a Wirtgen W 1200 F/T was used without a conveyor to maintain a low center of gravity and a W 2000 was used to mill the straightaways. The W 1200 left a 12-in. high windrow, which was then broken apart by a motorgrader. The material tumbled down the slope and was pushed along by a mobile broom and collected with skid steers for removal.
Precision was important at this stage, too.
Milling Foreman Josh Dyer said, “The tolerances are a lot closer. You will need a better ride at 200 miles per hour, and the total ridability of a race track exceeds that of a regular highway. The more precisely the milling machine can cut the surface, the more easily a paving machine can get those tolerances. If you are off to start with, the paver has to work twice as hard. If I can get close, it makes it a lot easier on everyone else.”
On the turns, crews laid a 4- to 6-in. cement treated base layer, a 2-in. asphalt base surface, a 1.5-in. level-up asphalt layer and a 1.5-in. surface layer of asphalt.
Three in. of material was milled off the straightaways and was replaced with 3 in. of new asphalt.
The surface layer will have granite aggregate in it, which is more resistant to breakdown over the years.
The paving equipment did not need to be supported on the tri-oval, Hajdasz said, except for the roller. It was supported with a custom-designed arm attached to a Komatsu bulldozer rolling along the apron.
Even with the support system in place, Hajdasz said it takes a lot of planning to successfully pave on this type of slope.
“There’s an incredible amount of surveying that had to go ahead of all of the operations,” he said.
Prior to every pass, the crews laid out string-lines that the equipment operators followed to ensure they were maintaining the proposed line and grade for each course of asphalt.
Since it takes a few passes of the paving train to pave the entire 48-ft. width, longitudinal joints became an issue. With drivers traveling at such high speeds, bad joints were not an option.
To ensure the joints’ quality, “we overpave the lanes by about 6 in. and then cut the longitudinal joints back out, so we will be able to achieve a very high joint density,” Hajdasz said.
The excess material was cut by a motorgrader with a pizza cutter. He said the process creates a much higher joint density than the sloughed off joints that are used on highway projects.
Quality control has been an on-going entity as the project has progressed, but NASCAR officials have set up testing sessions in August or September before the UAW-Ford 500 event Oct. 6 to 8. These sessions mostly are to test which tires are best suited for the new surface.
The Talladega track is just one of a series of raceways on which Sunmount has worked. It paved Texas Motor Speedway’s original track in 1995, which it redid in 1998 and 2001; Atlanta Motor Speedway in 1997; Homestead Miami Speedway in 2003; Richmond International Speedway in 2004; and Lowes Motor Speedway in Charlotte, NC, this spring. Its crews also completed a patch in the tunnel at Daytona International Speedway in 2004.
Approximately 35 Sunmount employees are working on site. It subbed out the concrete paving work on pit row and the fence removal and re-installation to Hale Milling Company in Aniston, AL, and the wall takedown and re-installation to Elrod Corp. in Indiana. Crews generally have worked from sunrise to sunset, seven days a week to ensure the track is ready for the big race.
“We knew it was going to be tight to begin with and it still is,” he said.
Hajdasz expects the entire project will be completed in mid-September, with the track work done by early August. CEG