Time and traffic had taken a toll on the Holland Tunnel, the four-lane I-78 thoroughfare connecting New York and New Jersey. Portions of the tunnel’s asphalt surface had settled and become crowned, leading to poor drainage and potential traffic hazards. The deteriorating drainage system led the Port Authority of New York & New Jersey to take action.
“It sounds like a simple mill and pave job,” said Raul Gonzalez, project manager of Crisdel Group Inc., South Plainfield, N.J. “What could be easier than milling a few inches, and replacing it with new asphalt? It sounds easy, but there was a little more to it than that.”
Key to the project was finding a paver that could cover the width of the tunnel in a single pass. That led Crisdel to use the Cat AP1055D asphalt paver.
“They [Crisdel] asked if one of our pavers could pave the entire width,” said Walt Suk, paving specialist of Foley Inc. “They wanted a machine that could be set up to pave at that width, do the job in one pass and meet rideability specs. That’s why we gave them a new machine and set it up with a wide lift kit.”
Foley also offered on-the-job expertise in the form of Suk and others. In fact, a Foley paving expert was on the job from beginning to end.
“We all worked with Raul and the operators at Crisdel on making sure the electrical grade and slope systems were properly set,” Suk said. “All involved were committed to following proper paving practices so the rideability goals could be met — and they were met.”
Suk believed proper technique was one “difference maker.” Another was using equipment that can help a crew succeed.
“We believe in this product so much that we provided it, on loan, to the customer,” Suk said. “We were so confident it could do the job that we simply delivered it to the job site, realizing that we had a customer in need — and a solution in the form of the AP1005D.”
The “solution” included an accompanying wide-lift package, which helped to evenly spread asphalt as far as 22 ft. (6.7 m) — no small task for a paver pulling that much weight. The electric screed also kept the mat temperature consistent across the entire width of the mat. “That helped a lot with rideability,” Suk said.
“We’ve had good success with the Cat Paver,” he said. “One key was the heated screed. Even the extensions are heated, which helped us reach our rideability numbers. Using that electric screed has been a big plus for us.”
Gonzalez and his crews need a few “big pluses” given the challenges of the job. Among them were:
• The Holland Tunnel had to be shut down. But the importance of the tunnel meant the milling and paving windows were extremely tight, with the road closing limited to seven hours at a time. “We had to be gone without leaving behind a sign we had been there — with the exception of the work we had done,” Gonzalez said.
• The paver had to be partially disassembled to fit through the tunnel; space continued to be an issue during the project.
• Ventilation had to be adjusted to keep workers healthy.
• Compactors had to achieve 98 percent density, yet couldn’t use vibratory settings.
• Asphalt had to be relayed to four vehicles before even reaching the hopper.
“We paved at 10 feet per minute, which would be incredibly slow on another job,” Gonzalez said. “On this job, it wasn’t. That was the right pace considering the conditions, and we kept moving steadily, which helped with smoothness. I wouldn’t want to make a living paving at 10 feet per minute. But in this case, I was thrilled.”
The Port Authority hired Crisdel to mill 3 in. (76 mm) off the existing surface and to place a new 3 in. surface with a 1.5 percent grade. Low spots were to be removed and water directed to a trench-type drainage system.
The Holland Tunnel consists of two “tubes.” Crisdel worked on the tube that brings traffic from New Jersey into New York. Work on the outbound segment will take place this spring.
The tube is 1.75 mi. (2.8 km) long, and work was divided into six 1,500 ft. (457 m) sections. “When milling, some areas were almost a reverse crown,” Gonzalez said. “As we milled, we ran a stringline every 50 feet to make sure there was a positive pitch. When we paved, we simply set up for 3 inches and 3.5 inches if there was fill. That gave us a nice smooth mat all the way.”
The new mix had a sieve size of 0.5 in. (12.7 mm), with the design calling for high fines, as well as high AC content and a low-void mix. A polymer 76/22 oil was used.
Role of Logistics
The challenge on this job was, pure and simple, logistics.
Milling began at 1 a.m. Saturday, with the tunnel re-opening to the public by 8 a.m. Weather was a key consideration because if the surface was milled, it had to be paved within 24 hours per the project specs.
It took the mill operator 2.5 passes to cover the typical width of 20 ft. (6 m). A single mill moved from the New York side toward New Jersey so the trucks were moving in the right direction. (They hauled the millings to New Jersey.) The exception was when making a pass closest to the curb. The mill and trucks moved toward New York so the cold planer could work tight against the curb to minimize hand-chipping. Trucks then went to the New York side, turned around, re-entered the tunnel and squeezed by the mill. “We had enough room with the mill, but not with the paver,” Gonzalez said. Milling each 1,500 ft. section required about 3.5 hours.
The following night — or morning — paving took place.
“The tunnel, again, would be closed at 1 a.m.,” Gonzalez said. “When we closed the tunnel, we had to sweep the ramps clean and put down a protective membrane that goes over the existing deck. The tunnel is actually a deck.”
It took until about 2:30 a.m. to get that work done, plus line up the paving train.
“Even though the tunnel was closed at 1 a.m., paving didn’t start until 2:30 a.m.,” Gonzalez said. It only lasted about two and a half hours. “We had to place the 650 tons (590 t) and get cleaned up and stripe — hopefully by 7 a.m. — so we had a little cushion. By 8 a.m. there had to be no sign of us.”
Staging Crucial, Too
The width of each tunnel tube — only 20 ft. (6 m) — required some efforts that Gonzalez hadn’t anticipated.
“The paving equipment had to go into the tunnel in the proper order,” he said. “It doesn’t seem like a big deal, but once the paver goes in that tunnel, you’re blocked off. There’s no getting around it. With auger extensions the paver is 15 feet, and the tunnel 20 feet. It’s tight inside and there’s no way to get past the paver.”
Staging consisted of loading the paver on a lowboy trailer on the New Jersey side of the tunnel early Saturday evening. But the lowboy wasn’t low enough, and the paver’s exhaust stack had to be removed. Police then held traffic while the lowboy, with paver aboard, made its way to New York.
“We’d get to the New York side and park the paver on a local street,” Gonzalez said. “Then, when they closed the tunnel at 1 a.m., the other equipment ’walked’ in. When those machines reached the New York side, we slipped the paver in front.
“We sent the paver early because it’s one of the slowest pieces of equipment. The rollers can walk in, which works well. It’s just another way to streamline things.”
The mix arrived from New Jersey. It took an hour, in traffic, from the plant to the tunnel.
“We loaded some trucks at 11:30 p.m. to make sure we had mix when we were ready to go,” Gonzalez said. “We had material on the road before the tunnel was even closed.” The loads were tarped to help retain heat.
Delivering the mix to the paver was another challenge. End-dumping wasn’t an option because of the low clearance in the tunnel. Crisdel uses material transfer vehicles, but the machines are too slow to come out of the tunnel to load material.
“Production would be horrendous if we just went with a transfer machine,” Gonzalez said. “It would take forever to deliver the material.”
That led the company to deliver mix, via 24 ton (21.7 t) tri-axles, to a staging area outside the tunnel. There, it was transferred to material transfer vehicles, which reloaded it in Flow Boy trailers. The Flow Boys then backed into the tunnel and deposited the mix in a second material transfer vehicle, which delivered it to the paver.
Electric Screed Helps
The Cat AP1055D asphalt paver worked well on the job.
“It’s been very good,” Gonzalez said. “We’ve been pleased with the smoothness.”
The temperature behind the electric screed remained consistent, he said. Besides keeping the mat at a consistent temperature, the electric screed also helps reduce fumes — a key benefit when paving in a tunnel.
“The Port Authority also has a great ventilation system,” Gonzalez said. “They can create positive and negative areas to move air.”
The authority essentially created a 20 to 25 mph (32-40 kmh) wind that blew from the rear forward. This allowed the crew to have a manufactured wind at their backs, and fumes to be pushed toward the New Jersey side of the tunnel. (Those in trucks and material transfer vehicles were protected by closed windows and the ventilation systems of that equipment.)
The rubber-track asphalt paver used a front-mounted screed that had 2-ft. (0.6 m) extensions on both sides.
“It’s set up for 22 feet, but we mostly paved at 20 feet,” Gonzalez said. “We do have a few variable areas where we have to open up to 21 feet or 22 feet.”
Smoothness went well, with no penalty for profile index results of 0 to 15.
“We averaged between 5 and 9, so we had very smooth pavement,” Gonzalez said. There were no joints to worry about because Crisdel essentially paved the entire width of the tunnel.
“The way we did it, we only had a transverse joint at the end of our paving day,” Gonzalez said.
Tough Density Target
Crews used two double-drum rollers — one in static, the other in oscillation — because of a fear that a vibratory roller would damage the concrete deck beneath the surface. A static asphalt compactor worked in breakdown mode, while the oscillating roller handled finishing work.
The rollers made a total of eight to 10 passes to reach density targets of 98 percent.
“They didn’t stop,” Gonzalez said. “They moved all night.”
Robert Buono, Crisdale’s in-house quality control technician, checked the mat throughout the job, monitoring compaction and temperatures. Immediately behind the screed, the temperature was about 280 F (138 C). “We held temperature very well, even with the transfer operation.”
It was among the most challenging jobs of Gonzalez’ career. “The paving was easy,” he said. “It’s the logistics behind the paving that created the challenge.
“If I think about it, it sounds very simple: Mill, and then pave 20 feet wide at a depth of 3 inches in one pass. It’s not complicated when you put it that way. But there’s quite a bit more to the story than that.”
Yet it all worked out in the end — to the extent that the job proved the Cat paver, which had been on loan to Crisdel, could perform.
“The paver did the job under tough circumstances,” Gonzalez said. “It performed so well we bought the paver when the job was finished.”