By: Bill Wilson Editor in Chief
No matter how thick the history, the Martinsville Speedway is still held together by the same one-of-a-kind paper clip. And the ownership team has successfully upheld the pledge to preservation, even when one racing incident called for complete track rehabilitation. The Martinsville Speedway, with long straightaways and sharp, steep curves forming the famous paper-clip shape, was trying to keep it together during one of the most intense NASCAR races of 2004. Rusty Wallace was trying to hold off a determined Jeff Gordon when the old track showed its brittleness. A chunk of concrete out of turn three spank the front left panel of Gordon’s car, eliminating him from contention and halting the Nextel Cup race for almost an hour while crews executed emergency patch work.
With Gordon disabled, Wallace was able to coast to victory, but the history and character of the Martinsville Speedway was still in danger.
Crews from APAC Atlantic, Danville, Va., had equipment at the site in preparation for a simple overlay job the next day. However, the untimely chunk of concrete was now messing with everybody’s schedule. The track was in need of a complete overhaul.
“Instead of coming in and doing an asphalt resurfacing job, they wanted us to go ahead and demolish the curves,” Ken Gavitt, project manager for APAC Atlantic, told Roads & Bridges. Gavitt’s team handled the grading and asphalt paving. “The project went from a $180,000 overlay to close to a $1 million rehab overnight.”
“Martinsville is one of the granddaddies of racetracks,” Warren Baker, project manager for APAC Atlantic-Ballenger, Greenville, S.C., told Roads & Bridges. Baker was in charge of concrete paving the turns. “The owner wanted to keep the character of the track.”
To help protect the personality, Martinsville hired a survey team to map the original form of the track. Shots were taken every 10 ft of the length and width of the track and a blueprint grid of the entire surface area was supplied to the contractors.
“We wanted the slopes and types of surfaces to remain the same,” commented Baker. “The intent was to make everything stay as close as humanly possible to what was already there, to keep the character of the track and what made it an interesting race to watch.”
Soft soil, hard job
Designers of the Martinsville Speedway took their first steps in the mid-1940s. The original track was completed in 1947. The foundation, however, was weak. Once the site of a 5-ft-deep pond, the Martinsville track was susceptible to drainage issues. Asphalt arrived on the scene in the 1950s, and it wasn’t until the mid-1970s when the decision was made to convert the turns over to concrete.
“The asphalt just rutted on the turns,” said Baker. “Between the heat, downpours and pressure of the tires the pavement just didn’t hold up.”
Gavitt was the first to arrive when the track was severely injured in 2004. He was familiar with the scene, and even worked on the track’s infield drainage problem. Gavitt’s first move this time around was to install a French drain and pull some of the moisture from the work area.
Initially, APAC expected the demolition of the existing concrete pavement on the turns to be more of a production. Gavitt was planning on bringing in a large hammer to break the 20-year-old track. But the steep 9° slopes couldn’t hold that type of equipment, so APAC brought in a Komatsu PC200 tractor loader with a 4-ft bucket and handled it like an aging sidewalk. Large pieces, consisting of a 31?2-in.-thick layer of concrete and 6 in. of asphalt, showed little resistance.
“The tractor loader had a thumb on it and just grabbed it and broke it,” said Gavitt. “(The older concrete) had a lot of fractures in it.”
Once the turns were reduced to nothing APAC dropped a 12-in.-thick Virginia 21B stone sub-base made up of coarse aggregate 3?4 in. and smaller in size. The inside edge of the turns proved to be particularly problematic. Since it served as the drainage base for the old track, the soil was softer than in other parts. Here, APAC decided to use up to 2 ft of stone. In all, over 4,000 tons of stone was used.
With a new platform in place, Baker moved in to handle the paving portion of the job. Using a basket assembly, 15-in.-long tie bars were placed 24 in. on center. Work consisted of placing the bars out on the slab and locking them down with steel basket stakes. In front of the operation was a GOMACO 9500 Placer machine, which allowed crews to place the concrete wherever it was needed on the turns. Following the traditional method of having mixer trucks handle the placement was next to impossible on the speedway. Again, the 9° banks made the ordinary job somewhat challenging.
“If you had a concrete truck on the low side of the track and tried to pour it out of the chute to the upper side you really couldn’t do it,” said Baker. “The 9500 has a boom on the back of it that the operator has control of and he can move it up, down, left and right. It allows us to place the concrete in a specific spot.”
Baker believes there were as many as 12 mixer trucks in line waiting to feed the concrete placer. The concrete plant was located 10 miles from the site.
Boxley Concrete supplied the mix, which proved to be another hurdle. The severe summer heat of July did not make for ideal paving weather. To help cool the mix, Boxley ordered a tractor-trailer full of ice, which was placed in the mixer trucks and served as part of the mixing water. Chemical retarding admixtures also helped the process, which required the concrete to reach a flexural strength of 650 psi in 28 days. Crews used a white membrane VDOT cure compound.
“The timeframe was pretty quick, so we really didn’t have time to tweak the mix,” said Baker. “Boxley primarily deals with compressive strength specs. We did some early breaks out of curiosity to see what strengths we were getting. We were comfortable letting some vehicles on it in a couple of days.”
Ice and extra admixtures certainly helped cool the summer temperatures but so too did the decision to primarily pave at night (2 a.m. to 9 a.m.). A custom-made GOMACO GHP-2800 handled the actual paving, working at widths of 28 ft.
“We basically had two longitudinal joints,” explained Baker. “We split the slab in thirds. The owner wanted us to keep the joint spacing as small as possible. He wanted nothing bigger than 10-ft by 10-ft squares.”
Two joints, running with the top and bottom of the track, are held together by the tie bars. There also are contraction joints, running to the left and right, which allow the concrete to expand and contract.
The surface texture of the track can sometimes decide a race. If the texture is poor, tire wear and grip is affected. APAC used two medium-roughness burlap drags to achieve the best results. The first was positioned directly behind the paver, which Baker said helped pull a little grout to the surface. A burlap drag was also attached to a work bridge a few feet behind the paver.
In terms of testing, APAC checked the slump, air content, unit weight, strength and smoothness. At the jobsite testing was done every 100 yd. APAC was shooting for a 5% air content, which, according to Baker, “is what we got.” The mix achieved a 11?2 to 2 in. slump, and all of the strength tests, which included fabricated beams and cylinders, were positive. For smoothness, APAC used both a
GOMACO Smoothness Indicator machine and a California profilograph.
“The two numbers were very comparable,” said Baker. “We could tell by the traces that there were no great big bumps or large deviations. The feedback we got from (racecar) drivers was very complimentary.”
“Thank-yous” also were heard for the new 100-ft extensions coming out of turns two (leading into pit row) and four. Now racers can accelerate harder heading into the straightaway, creating a smoother transition from concrete to asphalt.
Fast with the asphalt
After three days of paving, Baker returned the serve back to Gavitt for the final asphalt work on the straightaways. Using a Caterpillar milling machine, APAC chewed 3 in. of old pavement. Then, after laying down one pass of asphalt, Gavitt used a profile-milling machine to fine grade the surface before the final lift was placed. By being able to grade within a hundredth of an in., APAC removed a total of 49 in. of bumps and rough spots.
“Some of the lanes had no bump at all when we were finished,” said Gavitt.
The asphalt mix contained one of the highest binders on the market—a PG 96-22—and a fine mix of stones 1?2 in. or smaller.
Handling over 3,500 tons of the high-grade mix required extreme precision and efficiency. According to Gavitt, rollers had to be no more than 10 ft behind the paver, and the crew had to be quick. The job turned even more difficult making butt joints against the concrete corners. There workers had to manipulate material by hand.
“When you put it down you better have it right because it gets hard in about a minute,” he said. “And you never stop the paver until you’re at the end of the pass.”
A Roadtec 185 paver placed the material, which was 350°F at the plant and 320°F at laydown. APAC paved five, 12-ft passes forming four joints. Using a cutter on a motor grader, crews were required to slice 4 in. off the joint and apply a joint sealer before making another pass.
Working the rolling pattern (three vibratory passes, two static passes) was a pair of Ingersoll-Rand 110 double-drum vibratory rollers. APAC was shooting for 95% densities, and achieved between 95-98%, according to Gavitt.
Material testing at the plant was conducted every 50 tons, while checkpoints on the track occurred every 100 ft. APAC did nuclear density tests and cores on the first lift followed by another nuclear density test on the final lift. Smoothness was checked with a California profilograph. The requirement was less than 12 in. per mat, and Gavitt said the target was achieved.
“The track is holding up real well,” said Gavitt. “The first race they broke the track speed record by two seconds.
