Heavy winter surf on Unalaska Island was carrying rocks and boulders over the revetment and depositing them on the runway, creating an unsafe condition for the aircraft and passengers. There was a need to reduce the wave run-up on the shoreline so this condition would not occur. The Federal Aviation Administration and the State of Alaska selected the patented Core-loc shape as the best alternative to accomplish this goal while also presenting a uniform surface layer in the event an airplane overshoots the runway and slides down the revetment.
Core-loc is normally used as an armor layer to protect shorelines from erosion and has been extensively tested by the U.S. Army Corps of Engineers for that application.
A total of 960 pieces of 8 ton (7.3 metric tonne) Core-loc were cast in Tacoma and shipped by barge to Unalaska for this project.