Resurfacing a runway would not be too different from paving a highway if semi-tractor trailers weighed 100 tons, as some airplanes loaded with passengers do. But having all that weight riding on a runway and sometimes pounding into it in rough weather landings necessitates that the civil contractor doing the paving knows its business.
"To do it right, you have to be an elite civil contractor," maintains Rick Birge, manager of construction for Tilcon Connecticut Inc. "Other people try it and don't fare too well - we fare very well ourselves."
To begin with, a runway at the Bradley International Airport in Hartford, Conn., is 16 inches thick, whereas the average interstate highway may be only 9 or 10 inches thick, Birge estimates. Then, a 25-foot-wide paving machine must be utilized, which is wider than ones used on a highway. Tilcon leased a paving machine with extensions for the extra width.
"It ran 24 hours, seven days a week," Birge says of the paving operation. The runways are as jumbo as the jets that land on them. Runway 6-24 is 10,000 feet long, 250 feet wide and used 63,000 tons of blacktop. The second runway that Tilcon paved, runway 15-33, is 7,000 feet long, 190 feet wide and required 42,000 tons of blacktop.
"Working 24/7, you can get a lot of work done," Birge points out. "Quality control was pretty intense. We had numerous people dedicated to that all the time, watching the percent of voids, the oil content, the gradation of the aggregate, temperatures - there's a lot of stuff they have to watch.
"We probably had seven different crews there day and night," he continues. "Security was very high. State police were at all the gates. They had their canines there and everything, They did inspections of all the vehicles, and you had to have certified escorts bringing the trucks in and out.
"Most of the truckers were independent - we could have had 30 a day," Birge estimates. "Every person goes through a security check - fingerprints, pictures, the whole nine yards. Just the badging process took four months to accomplish. We probably badged over 200 people."
Run of the Mill
The around-the-clock operation was necessary to minimize downtime on the runways Tilcon repaved. "They wanted it back up as soon as possible," Birge explains. The repaving required milling four inches off the runways and then paving it back in two, two-inch passes called lifts. "Usually, you can only do three inches at a time," he notes.
A deteriorated runway looks pretty much like an old highway, with cracks and holes in it. Birge estimates the runway has not been repaved in 20 years. "They do corings, and the engineers analyze the corings and see how far down it's deteriorated," Birge says of the runways. "The pavement was only deteriorated for maybe two inches, but they had us go four inches. We also groove the runway to help water run off it during rain."
The first repaying job, on runway 6-24, cost $ 13.5 million. It was started in April 2009 and completed in June. The company's crews - who already had been approved by security to work at the airport - then simply moved over to runway 15-33 for the second, $6.5-million repaving job, which started in July 2009 and was completed in October. Already having gone through the four-month badging process was a bonus on the second leg of work.
To repave the main intersection of the runways, the airport had to be shut down totally from approximately 11 p.m. to 6 a.m. on Fridays, Saturdays and Sundays for three consecutive weekends.
Why a Duct Bank?
In addition to repaving the runways, Tilcon upgraded the existing drainage system on runway 6-24, and pulled approximately 122,000 lineal feet of new wiring for the lights, which also were upgraded along with the transformers. New signage and duct banks were installed.