Like highway and bridge projects, airport runway improvements are important infrastructure jobs and Diamond Materials LLC of Wilmington, Del., is doing its part to bring them to the Greater Wilmington Airport.
The $10 million Delaware River and Bay Authority Airport Facility project involves milling and overlaying the airport’s main runway and rebuilding taxiways.
“We’re extending the main runway 1,200 feet and constructing a new taxiway,” said Bill Beaudet, general superintendent of Diamond Materials LLC. “The milling is 150 feet wide and is a variable depth mill — it will average anywhere from a half inch to three to four inches. The compaction on the paving is 95 percent with joint compaction, which is different from typical highway construction where they only check on the regular mat. This is where you have to take the extra time and effort and compact your joints.”
The project began in June 2008 and is on track for completion in June 2009.
In total 250,000 yds. (228,600 m) of dirt will be moved and total paving on the job will be approximately 45,000 tons (40,823 t).
Diamond Materials has done all of the grading, re-spreading of topsoil and all of the utility work — water, sewer and electric upgrades along the sides of the runway for new taxi lights. The dirt was moved onsite and some offsite to various locations. “Most of it was an export job — we couldn’t reuse most of it onsite,” said Beaudet.
Milling work at the airport was an eight-day process, while paving took approximately two weeks. “We had some real good shifts; we were able to get in and out of there,” Beaudet said.
Initially, Diamond Materials employed a shift of four 10s, with some night work. “During peak operations we probably have had 15 to 20 people onsite at all times,” he said.
This project is on the higher end of the size scale for the jobs that Diamond normally does, according to Beaudet. “We are more of a paving contractor. We do site work and site development, but our main forte is milling and paving work.”
The biggest challenge on this project has been working with the facilities at the airport.
“We try to tie in the existing runways and keep clear of that and working with the different facilities, such as the Air National Guard and Army National Guard,” Beaudet said.
Equipment on the job includes earthmovers, graders, some large John Deere dozers, excavators and a large number of trucks for the exporting of the soil that can’t be reused onsite. In addition, Diamond is using a Caterpillar 1055 paver and an RX900 Roadtec cold planer.
The RX900 is a recent addition to Diamond’s fleet. “We just recently purchased the Roadtec — it’s a new machine, capable of cold in-place recycling, which was our main purpose for buying the machine. Plus, it has a 12-foot head, which will allow us an advantage on our other work that we do for the Department of Transportation in Delaware,” said Beaudet. For this project, Diamond Materials’s RX900 also is equipped with a Topcon System 5.
Although the airport runway is a straight milling job, Diamond Materials has some projects coming up that involve cold-in-place recycling. “What you’re actually doing for cold in-place recycling is grinding the existing road to a depth of four inches, taking that old road material and grinding it in the mill along with an emulsion,” Beaudet said. “You take that material, transfer it right off the mill to a paver, you relay it back into the same hole and roll it in and that is what’s called cold in-place recycling. The Roadtec machine will do that for you.”
The Roadtec RX900 is equipped with a 950 hp (708 kW) Caterpillar engine and can cut up to 14 ft. (4.2 m) wide and 14 in. (35.5 cm) deep. According to Roadtec, a 30,000-ton (27,216 t) pile of RAP with an average of 6 percent liquid AC content is the equivalent of approximately 28,200 tons (25,582 t) of clean aggregate, plus 420,000 gal. (1,589873 L) of liquid asphalt. It is this material that can replace virgin materials in new mix, and the recycled materials are as good as virgin rock or AC.
The RX900 was purchased from Andy Pennington, regional sales manager of Roadtec.
“We’ve done business with him before, and Andy is great to work with,” said Beaudet. “He is great with service — right on top of everything. Anything we need with technical support, he is right with us. And parts are always available. There is never a wait for parts — great service feature there.”
Pennington has often been on the site over the course of the project, as has John Grizzle, service technician at Roadtec, making sure that the newly purchased RX900 is working well for Diamond Materials. CEG