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AFCEC awarded patent for new runway repair technology

The Air Force Civil Engineer Center Lab research team perform the dry placement of K-Fill CLSM

The Air Force Civil Engineer Center Lab research team perform the dry placement of K-Fill CLSM during a field evaluation. The Air Force Civil Engineer Center’s laboratory at Tyndall AFB, Florida, registered its second consecutive test on the material in October 2019. (Courtesy photo by Grace Bland, K2)

The Air Force Civil Engineer Center Lab research team place a hot-mix asphalt cap on top of the K-Fill CLSM backfill during field evaluations.

The Air Force Civil Engineer Center Lab research team place a hot-mix asphalt cap on top of the K-Fill CLSM backfill during field evaluations. The U.S. Patent and Trademark Office recently granted the Air Force a patent for the innovative runway repair solution developed at AFCEC. (Photo Courtesy by Grace Bland, K2)

The research team place K-Fill Controlled Low-Strength Material into a crater using a 10.5 cubic yard concrete truck in July 2019

During the first field evaluation of a solution developed by the Air Force Civil Engineer Center’s Laboratory, the research team place K-Fill Controlled Low-Strength Material into a crater using a 10.5 cubic yard concrete truck in July 2019. K-Fill CLSM and K-Concrete were created under the Cementitious Materials Patent recently awarded to the Air Force. (Courtesy Photo by Grace Bland, K2)

The Air Force Civil Engineer Center’s Readiness Directorate research team fills craters using K-Concrete.

The Air Force Civil Engineer Center’s Readiness Directorate research team fills craters using K-Concrete. The innovative runway repair solution was developed by members of AFCEC’s Laboratory at Tyndall Air Force Base, Florida. The solution allows rapid airfield damage repair teams to quickly repair runways using materials that can be gathered locally, like sand and clay. (U. S. Air Force photo by Andrea Kennington)

TYNDALL AIR FORCE BASE, Fla. - The U.S. Patent and Trademark Office recently granted the Air Force a patent for an innovative runway repair solution developed at the Air Force Civil Engineer Center. 

The formula, developed by members of AFCEC’s laboratory at Tyndall AFB, Florida, will allow Rapid Airfield Damage Repair, or RADR, teams to quickly repair runways using materials that can be gathered locally, like sand and clay.

Additionally, the Air Force expects a significant cost savings, said Craig Mellerski, AFCEC Requirements and Acquisition Division chief. Using locally sourced materials for three quarters of the mixture will save the Air Force around $1,140 per cubic yard.

The road to inventing cementitious material began in 2015, said Mellerski.

“The Air Force needed an alternate backfill solution that can be used in remote areas to patch damaged runways allowing critical mission operations to resume quickly,” Mellerski said. 

The AFCEC research team set out to create an adjustable, rapid-setting concrete solution, clocking in four K-Fill field evaluations and three K-Concrete field evaluations, and testing different combinations of sand, soil, clay and gravel mixed in with fly ash and an activator solution. 

Eventually, they landed on a formulation they dubbed “K-Fill.” Contrary to popular belief, the K does not stand for Kara Griffith, the last remaining member of the original research team.

“Potassium Silicate Powder is the preferred ingredient in the activator solution,” said Griffith. “’K’ is the chemical symbol for Potassium — but I’m flattered people think it’s named after me.”

While K-Fill won’t be in the field for operational use for about two more years, securing the patent is a major step toward equipping RADR teams with this mission-critical tool.

“Whether it’s damage from an attack or natural disaster, an out-of-commission airfield in a remote location presents a huge risk to mission and Airmen,” said AFCEC Expeditionary Engineering Division Chief Maj. Khary Davis. “You can’t get supplies if you have a blocked transportation path.  Providing an option to increase the use of in-situ materials allows additional options to civil engineers and can help reduce the time to reopen airfields and logistic chains.”

With supplies at the ready, RADR teams can fill and set concrete in just over an hour, bringing airfields back online quickly and at a cost savings to taxpayers.

Five years after starting this journey with now-retired lab members Dr. Derek Lovingood, Michael Henley and Jeffery Eichler, Griffith is grateful she was able to take the project over the finish line for her team.

“It means a lot to me that I was able to finish this work, and that I was able to complete the goals we had originally set out to complete when all of us were here,” Griffith said. “I’m glad I didn’t fail my team.”