When Perfection is the Only Option

Crew takes on challenging track, memorial project

It’s a beautiful fall day in New England, but no one from the T.L. Edwards crew seems to notice. Their conversation centers on tolerances, paving speeds, split-drum compaction, haul trucks and logistics.

As they talk, one word surfaces, over and over: Perfect.

“This job has to be perfect,” says Rob Edwards, equipment manager of the firm based in Avon, Mass. His father, Terry “T.L.” Edwards—the owner and namesake—says the same thing. So does foreman Peter Starrett, and members of the crew.

If there is little margin for error most days, there is no margin for error this day. Everything needs to be perfect for this job—and what it stands for.

The job is a running track for Sandwich High School, located on scenic Cape Cod, Mass. Paving a running track has created a need for great precision.

The crew is worried about perfection for another reason—for what the site represents. This day also marks the paving of the base for a memorial to fallen veterans, and in particular Capt. Gerald F. DeConto, a 1974 graduate of Sandwich High School.

DeConto spent his career in the military and died in the Sept. 11, 2001, attack on the Pentagon. His family, friends and the Sandwich community chose to honor their native son by building a new track and football field in remembrance of him and others who served their country. It took years, but the necessary funds were finally gathered for paving both the track and memorial area.

The school will once again be able to host events—something it couldn’t do for the better part of a decade because of the track’s poor condition. And those who visit the brand new track also will see the memorial.

That’s why T.L. Edwards wasn’t just talking about mat deviations when he said, “This job has to be perfect.”

Job description

The project actually consisted of three separate paving components. The first was to pave the infield event and memorial area, between the track and what will be the football field. It was essentially a parking lot-type project.

The track comprised the other two components: A 6.7 m (22') wide lift that will be the running track, and an adjacent 3 m (10') wide lift on the outside of the running surface for non-competitors such as coaches, timers and others.

The project started with fine grading and soil compaction. A paver then made a pass with stone dust to ensure elimination of all deviations, followed by another compaction pass.

Next it was time for asphalt. A Cat® AP555E placed a 38 mm (1.5") binder with a stone size of 19 mm (3/4"). Then a 38 mm (1.5") surface coat was placed, with 13 mm (½") stone.

The project specified a cross slope of 0.75 percent for drainage, but allowed that slope to deviate to a maximum of 12 mm (0.04'). “That’s how much room they gave us for grade deviation,” said Rob Edwards. “Less than half of an inch around the whole track.”

That tight margin led to the use of the Cat Grade and Slope system. “We weren’t afraid to go with that new technology because Caterpillar is very thorough when they put a product out,” Rob Edwards said. “We know it will work.”

Another contractor later applied a thin rubber surface.

The paving

A Cat AP555E Asphalt Paver with an AS3251C Screed began the day by paving the memorial area. That job was handled with ease, but the real challenge was the track. Besides the need for precision, hills limit access to the site—requiring even more detailed logistics.

The surface lift started with a Cat® AP1055E Asphalt Paver placing asphalt near a corner, at the “top” end of the oval track. But the paver did not have a strictly horizontal starting point. Instead, the screed and a piece of wood created an angle. (Later, when the paver circled the track, it was able to work to the low point of that angle, then pull the screed in and pave tightly along the angled starting point—and drive off the unpaved, outside portion of the track.)

The AP1055E extended its AS3301C Screed and paved at a width of 6.7 m (22'), enabling the entire running surface to be covered in a single pass. “Working at that width was not a problem,” Starrett said. “We’ve worked at 28' (8.5 m) before.”

The paver turned the first corner, and then another. The AP1055E then was joined by the second paver, an AP555E—just before a straight stretch of the track. The standard 2.4 m (8') screed on the AP555E was extended to 3 m (10') and handled the surface outside of the running area. A crown separated the two pavers, and was left intact for drainage purposes. Water on the track would drain toward the inside field, and water on the outside surface would drain away.

The AP1055E, on the inside, moved faster than the AP555E on the outside. In particular the AP1055E gained time as it traveled through turns. When the AP1055E had circled the track, it paved to its starting joint. It drove off the outside portion of the track that the trailing AP555E had not yet paved.

The AP555E then worked its way to its starting point—further along the track than where the AP1055E had started—and eventually backed in to create the longitudinal joint before paving a walkway as it exited the facility.

The mix was placed at a temperature of about 149º C (300º F). The trucks remained tarped; heat loss was an issue because the trucks had to arrive at the site, back around the track and line up. The material was end-dumped into both pavers.

The pavers worked at about 457 m (1500') per hour. In other words, it took about an hour for them to pave the track.

Grade and Slope is key

The crew had a tough job, but it was made easier with the Cat Grade and Slope system on the pavers. “We like the way operators on both sides of a screed can see what the other sees,” Rob Edwards said. “That’s in addition to the accuracy it delivers.”

Accuracy was crucial. The slope at the straightaway started at 0.5 percent and transitioned to 0.75 percent for the remaining three turns. The Grade and Slope read off a previously placed and inspected concrete drain for grade.

Key members of the Edwards crew relentlessly monitored the results from the screed, using levels to double-check accuracy. Crew members rarely walked on the mat, and when they did, special boot covers helped to increase flotation.

Compaction

The CD54 handled breakdown compaction behind the AP1055E. The roller’s offset split drums, and their wider coverage area, maximized efficiency while compacting the 6.7 m (22') mat. The offset drums also provided a tight turning radius without damaging the mat—a key feature when compacting an oval track.

“The CD54 doesn’t stretch the mix,” Rob Edwards said. “It doesn’t push and pull and tear.” It’s also maneuverable, he said. “It weighs 22,000 pounds (10 metric tons) and handles like a go-cart.”

Starrett likes the split-drum roller’s versatility. “We can use it when we need a static, and we gain by having vibratory available. It’s really a static roller with extra compaction.”

A CB54 took on breakdown compaction behind the AP555E. Both the CD54 and CB54 were able to achieve compaction in three passes, with a movement up and back and up counting as three passes. The rollers worked from immediately behind their respective pavers to a few hundred feet back. The compactors worked next to, but never crossed over, the crown. A Cat CB24 did the finishing work.

Victory lap

The machines and crew met the goals. All the experience and attention to detail paid off: Everything was perfect. In a little more than an hour, the crew had moved past the memorial site. Given the requirements, it proved to be the track’s first victory lap.

Tandem Vibratory Rollers make a nice, smooth surface