The 11,000-ft.-long airfield runway at Ft. Campbell, Ky., is one of the longest in the Department of Defense and fulfills an important function in aiding military preparedness. Like the soldiers of the 101st Airborne Division it serves, the runway must be ready for almost anything.
In addition to the normal traffic of Blackhawk helicopters and C-130 cargo planes, the airfield handles unusual landings, including being an alternate landing site for NASA’s Space Shuttle when it lands piggy-back aboard a 747. Last summer’s hurricane season brought other unusual “guests” as fighter jets from Florida escaped the severe weather conditions and came to Ft. Campbell.
The runway was last paved in 1991. The Army Corps of Engineers (COE) laid out some special requirements for the repaving of the runway with an eye toward promoting smoothness. The stipulation was that if a longitudinal joint fell below 170 degrees, the cooler material would have to be cut away in order to form a hot joint and get better density.
The maintenance people of the Rogers Group, who had been selected to handle the paving duties, constructed a special cutter wheel to meet the COE’s requirements. The crew attached the cutter wheel to the rollers in order to shave off hot-mix asphalt (HNMA) when the joint cooled to 170F (77C) degrees. The Athey loader scooped up the leftover HMA and conveyed it into a truck to keep the material from interfering with other paving operations.
“We paved the full length of the runway without stopping and used 2,800 tons of asphalt on each pull we made,” said Gary Johnson, construction manager of Rogers. “We also put down a tack coat on the longitudinal joints to ensure a tight fit.”
The attention to detail and special equipment paid off as the Rogers crews met the requirements of 95 percent density on the mat and 92 percent on the joints.
The paving crews also were able to achieve exceptional smoothness on the 200-ft. wide runways, with profilograph readings between 2.5 to 3 in. (6.4 to 7.6 cm) per mile. These smoothness numbers were well under COE’s requirements.
Rogers Group laid the foundation for this successful project with careful attention to scheduling. The airfield was shut down for 30 days to allow milling, paving, grooving, and striping. Rogers was allotted three weeks for paving, but completed it in just 12 days.
“We ran our operation 24 hours a day to get the two-inch binder course laid down,” said Johnson.“That allowed us to pave during the daytime only for the two-inch surface course, allowing us to pay special attention to our smoothness requirements.”
Rogers had done the last runway paving 15 years ago.
“The old runway had held up quite well over the years and this new paving project was very successful,” said Johnson. The Rogers crews used a mix that was similar to Superpave with a limestone aggregate. The entire project required 58,800 tons of asphalt.
Brian Moser, district engineer of the COE, supervised the project, and was pleased with the final result.
“The project was a challenge logistically in coordinating the earth moving, milling and paving,” said Moser. “In the end it met all the criteria for smoothness, mix performance, and density.”
(Reprinted by permission of National Asphalt Pavement Association from its “HMAT” magazine, November/December 2006.)