Brooklyn Bridge Micro Surfaces for Success
Brooklyn Bridge relies on micro surfacing for a smooth ride for its more than 100,000 average daily vehicles. Asphalt Paving Systems is there to help.
When the Brooklyn Bridge opened for use May 24, 1883, thousands of people attended the opening ceremony. Ships filled the East Bay, President Chester A. Arthur crossed the bridge to celebratory cannon fire, bands played, banquets were held and there was a great fireworks display.
To this day, the Brooklyn Bridge remains an icon connecting the boroughs of Manhattan and Brooklyn across the East River. When Asphalt Paving Systems (APS) of Hammonton, New Jersey, had the chance to pave this piece of history, the company eagerly agreed.
APS was a subcontractor on the project, working alongside Commodore Contracting, Mount Vernon, New York, who had been awarded New York City Department of Transportation’s bid for bridge maintenance that year. APS’s role was to apply a double application of micro surface.
“The issue with Brooklyn Bridge is weight,” APS Vice President Ken Messina said. “You can’t do a 2-inch lift of asphalt because of the weight limit and because of utilities, so there aren’t many other options.”
That is why every eight years or so, the bridge is micro surfaced. APS has performed that application the last three times it was required.
Micro surfacing is also a suitable solution for the bridge because it doesn’t experience much truck traffic and a great deal of the weight is borne by the metal grid and bridge deck, Messina said. “Micro surface seals that and offers a smooth riding surface for the driving public,” he added.
Before APS could apply its double application of micro surface, Commodore had to remove the previous application and powerblast any remaining material stuck to the bridge. Then, the APS crew used a broom and blower to remove any residual dust from the bridge deck before applying a tack coat to the concrete-and-metal surface for maximum adhesion.
The bridge, which has three lanes traveling in each direction, was micro surfaced over six nights, back to back. Each night, the crews applied micro surface to two lanes, returning to cover those same two lanes with a second application the following night.
The double application of Type 3 micro surfacing, which is constituted of more coarse aggregate than types 1 and 2, offers a strength of 28 pounds per square yard with each lift. Type 3 can be applied at a heavier application than types 1 and 2.
“APS puts forth a lot of effort to ensure quality. Not only quality workmanship, also quality mixes,” Messina said. To ensure proper mix percentages and maximum cure times were being achieved, APS’s lab technicians pulled samples of the materials used and tested them at their lab on a nightly basis. “Closely monitoring the materials allows for us to be one step ahead of any issues that may arise with producing this difficult mix.”
The double application was required due to the average daily traffic traveling on Brooklyn Bridge, totaling more than 100,000 per day.
To complete the job, APS used an M210 micro surfacing truck from Bergkamp, Salina, Kansas.
“All of our micro surfacing equipment is from Bergkamp,” Messina said. “We have three continuous and eight truck-mounted machines, but the length of this project—only 3,500 feet—didn’t lend itself well to continuous paving.”
Due to weight restrictions on the bridge, APS could not fully load trucks delivering materials to the job site. Instead, they could only load the M210 with about 6 tons of aggregate and 150 gallons of emulsion, which is half of the tank’s capacity.
Because of those weight limits, APS could only travel around 330 feet per load. “Instead of doing two or three loads per side, we were doing eight,” Messina said. Although handwork on this job was minimal, he said it was very important to have talented crewmembers on the ground to ensure there was no visible joint at those stops and starts for good rideability. “We also tried to stop and start on expansion joints.”
Traffic control presented another challenge. To prevent the traveling public from entering the work zone, APS placed a safety cone every 30 feet, compared to every 80 feet on its interstate jobs. APS also had to deal with extended travel times going to and from its staging area beneath the bridge.
“We were running four micro surfacing trucks on the project, but they’d get stuck in traffic and had to go over the entire bridge and then turn around to get to us,” Messina said.
Another unique aspect of the job was that, unlike most micro surface projects, it had to be rolled, “not so much for compaction but to squeeze any water out of the mix to reduce the cure time.”
“Type 3 is notorious for its slower set-up time,” Messina said. They were also paving at night and over water, so there was more humidity and a higher dew point, both of which would also slow down cure time.
Simultaneously, the APS crews could only work from 10 p.m. until 5 a.m., and the first one to two hours of each shift was spent protecting scuffers, which drain water off of the bridge, as well as other utilities and expansions, with plastic sheeting.
To return the road to traffic by 5 a.m., they had to speed up cure time. To achieve this, APS used RoadScience ARRTEKK 1295 emulsifier.
“That’s another great reason to use polymer-modified micro surfacing for this job,” Messina said. “New York City never sleeps, and neither does the Brooklyn Bridge.”
It’s a job Messina will always remember. Having finished micro surfacing the bridge around the Fourth of July, he can recall the American flags flying from its parapets and the view of the Statue of Liberty and Freedom Tower from the bridge.
“The Brooklyn Bridge is iconic: the era it was constructed, the history behind it,” Messina said. “We’ve done work on other bridges, but this one will always hold a special place in my heart.”