Joint project develops airfield damage repair materials, techniques
January 23, 2013
Wanted: Airfield Damage Repair material, equipment and procedures to repair runways used by U.S. Air Force (USAF) fighter jets and cargo planes. The goal is to repair 120 craters in 6.5 hours using up to eight teams.
This ad may not have appeared on the Federal Business Opportunities website, but ERDC, the U.S. Air Force Civil Engineer Center and the Air Force Research Laboratory have combined forces to develop a solution to the runway repair issue.
Jeb Tingle, ERDC program manager for the Airfield Damage Repair (ADR) Modernization Program said, "This project is part of the Air Force's Civil Engineer Modernization Program, sponsored by the Air Combat Command at Langley Air Force Base, Va."
The Critical Runway AssessmenT and Repair, or "CRATR" "is a Joint Capabilities Technology Demonstration (JCTD) Program co-sponsored by USAF and the Office of the Secretary of Defense," Tingle said.
USAF identified two repair categories for the JCTD. Expedient repairs provide an accessible and functional minimum operating strip that will sustain 100 passes of mission aircraft. Sustainment repairs are completed when operational tempo permits and are an upgrade to expedient repairs that are expected to support 5,000 passes of mission aircraft. Both types of repair are expected to be completed within four hours.
"The general objective of the ADR Modernization Program is to update the Air Force's ADR capability by developing new scalable ADR solutions," Tingle said. "The specific objective of the CRATR JCTD was to demonstrate new ADR technologies in a relevant environment that simulates specific threat scenarios. Current test objectives are to evaluate the suitability of the new repair materials, equipment and methods under inclement weather conditions such as sustained cold weather and rain conditions."
A cold weather test took place from March 25 through April 6, 2012 at Malmstrom AFB in Great Falls, Mont. The test site was selected due to the area climate in the spring and because it was a closed airfield with thick Portland cement concrete (PCC) pavement.
Lulu Edwards, an ERDC ADR team member, described the cold weather test conditions. "The temperatures ranged between 30 and 35 degrees," she said. "The demonstration at night was a good secondary test because visibility was decreased and the airmen's energy levels were lower due to working earlier during the day. This is more representative of what may actually happen during an actual attack."
A wet weather test took place in June 2012 at Tyndall AFB, Fla. The tests' objectives were to evaluate the suitability of the current ADR technologies and the techniques, tactics and procedures to identify modification requirements.
Co-team member Haley Bell explained that the wet weather test was conducted during the day and under a constant spray from an elaborate water sprinkler system that provided the equivalent of 3/8-inch per hour of rainfall. "It was hot and we were all red within minutes of going onto the airfield test area, but we had to give the airmen a chance to work in the wet conditions without us looking over their shoulders," she said. "The constant stream of water looked inviting for the observers."
In both tests, the ERDC team trained airmen from the Rapid Engineer Deployable, Heavy Operational Repair Squadron Engineer (RED HORSE) squadrons and Prime Base Engineer Emergency Force (Prime BEEF) units to use the materials, equipment and methods for crater repair.
"The experience of the airmen varied from experienced to first-timers," Bell said. "We used a crawl, walk, run method for working with the airmen. Crawl was classroom time; walk was hands-on demonstrations with us watching over their shoulders; and run was the Air Force team performing two series of crater repairs with us observing from the sidelines."
For the tests, the airmen operated equipment such as all-terrain vehicles, Caterpillar SW45 and SW60 wheel saws, Caterpillar 279C compact track loaders with bucket and broom attachments, self-propelled Husqvarna FS 6660D wheel saws, Volvo wheeled excavators, Caterpillar wheeled excavators, John Deere front-end loader, Caterpillar TH350B telescopic forklifts, lowboy trucks, and CemenTech tow-behind simplified volumetric concrete mixers.
"The airmen each had multiple assignments on the team and used more than one piece of equipment during the training," Bell said. "The Air Force crater chief determined who performed what tasks to create the most efficient team for the actual test."
The marking team marks the areas that require repair. The cutting team uses saws to outline the repair areas. The excavation team breaks up the damaged runway and removes disturbed subsurface materials. The backfill team filled the excavated areas on the runway ensuring the repair will support heavy aircraft operations. The capping team places a level, rapid setting cap over the fill material ensuring the repair meets the time and strength requirements.
"The rapid setting flowable fill material is self-leveling, self-compacting, and flows under gravity to fill all available voids," Tingle said. "Following the placement of 4 to 6 inches of dry material, water is metered onto the surface, and allowed to percolate through the dry material."
The rapid set material hardens in 20 to 30 minutes depending on the air temperature and the use of additives. The demonstration proved that the airfields were ready for traffic within two hours of the cap being placed.
The ERDC ADR team will bundle up and head to another cold weather demonstration in February at Malmstrom AFB, Mont.
"We are proud to have the opportunity to work on this project," Bell said, "knowing that we are helping the warfighter and increasing their capabilities."
Read more about the 11-step airfield damage repair program at http://erdc.usace.army.mil/gsl/11-step-program-repairs-airfield-damage/.