Hillsboro Airport, located in the western suburbs of Portland, is Oregon’s largest and busiest general aviation airport handling over 250,000 annual flights. The 6,600-foot-long (150-foot-wide) primary runway is host to many local corporations such as Nike and Intel and plays an integral role in offsetting air traffic in and out of Portland International Airport. High air traffic demand, coupled with the Northwest’s four season climate and annual precipitation of 40 inches, requires the highest performance in runway protection.
Engineering firm WH Pacific teamed up with Portland based contractor Roger Langeliers Construction (RLC) to begin evaluation on potential high quality alternative coatings. WH Pacific’s primary requirements for their clients were to find a protective runway coating that met a “skid neutral or better” surface resistance, maintained environment safety and was cost effective over the long term.
The growing team called on Carbonyte Systems Inc. (CSI) to finalize specific mix designs of CarbonSeal-FR. CarbonSeal-FR consists of a base, medium pen asphalt emulsion which is prepared for advanced interfacial bond and shear strength through the chemical “weaving” of polymer grafted and dissolved ground tire rubber (GTR) to make a superior rubberized asphalt pavement coating. Daytime applications of CarbonSeal-FR involve a 20% cut by volume but in order to facilitate curing for Hillsboro’s nighttime application, the CarbonSeal-FR would only be cut to 15%.
Extensive evaluation of the CarbonSeal-FR included full scale field testing of skid resistance, utilizing a continuous slip friction tester. This type of runway measurement system meets all FAA and ICAO specifications for friction measuring devices and demonstrated that the CarbonSeal-FR coatings were skid positive, achieving the skid neutral or better requirement.
Oregon Department of Aviation (ODA) also spent time validating CarbonSeal-FR’s ability to be immediately striped upon curing. Previous systems used by ODA required several days of curing before striping.
On an early September evening, with air/pavement temperatures in the low 60s, crews began crack sealing operations at 7 p.m. By 10 p.m. RLC’s project manager Jim Cross and his spray crews were poised to enter the runway and begin the first spray application of the CarbonSeal-FR.
Surface temperatures were well into the 50s as trailer-mounted light towers illuminated the way for the PavementSaver spray machines while they lay down 10-foot swaths of material totaling 0.25 gallons/square yard.
The first section of the primary runway, described as the main touch down area before the intersecting runways, was completed with a two coat application by 3 a.m. the next morning. At around 5 a.m., just two hours after the application, temperatures had fallen into the low 50s and an unexpected isolated rain cell passed directly over Hillsboro’s runway before the coating had yet fully cured.
At 9 a.m. airport inspectors had arrived to walk the affected area and found that the coating had not only held up but was ready for touchdown traffic.
RLC crews, lead by supervisor Kenny Wood, quickly re-staged for the remaining sections of the primary runway. Air temperatures rose into the 70s and surface temperatures were averaging 115° F.
RLC picked up the pace and had split off a second team to capture the live runway intersection at 12 p.m. The application window for the runway intersection would be short as RLC crews were only allotted one hour to capture and apply two coatings before air traffic resumed.
By 12:50 p.m. the crew pulled the last cone and the first turbo prop aircraft lifted off at 1:15 p.m. without issue. Crews resumed spray application on the remaining section of Hillsboro’s primary runway, completed the final pass, and re-opened the runway at 7 p.m.