Resin for runways

Patented by Pennzoil three decades ago, a petroleum-based wax resin long used to stabilize dirt roads in mining operators could prove to be an appealing alternative for runways.

Bruce Coulthard, president of PZS Stabilization of St. Helena, Calif., has set to work in recent months marketing PennzSuppress D for use on runways—paved and unpaved—touting benefits including low cost, high strength and traction, and environmental safety. Unlike other materials used to stabilize roads, PennzSuppress hardens into a resin that is not water-soluble, and holds up well to heavy use over time. It can bind dirt and gravel on a backcountry airstrip, and coat asphalt or concrete with a protective layer that sheds water while still providing good traction and extending the life of the surface.

“This is sort of my baby, introducing this to the aircraft industry,” said Coulthard in a telephone interview, noting the product is currently lined up for application to 1,100 miles of unimproved federal roads along the California-Mexico border, and has also been applied to auto racing tracks.

Coutlhard said PennzSupress hardens into a surface that is non-toxic, and impermeable to water, so it won’t dissolve and leach into nearby groundwater. He pointed to independent laboratory tests conducted a decade ago on behalf of state agencies in Texas. PennzSupress binds dirt, gravel, and other materials into a solid base that traps dust, and could allow even a paved runway to be resurfaced for a fraction of the cost—about $0.15 per square foot for a surface coating, and $0.50 per square foot if it is applied in a deeper layer using a milling machine.

For a runway that is 1,500 feet long and 50 feet wide, or 75,000 square feet, that translates into a cost of $11,250 for a surface coating, or $37,500 for a deeper application.

“The savings are massive,” Coulthard said.

Coulthard said it can also be used to touch up the touchdown zone, and even a topical application has held up to thousands of vehicle passes in laboratory tests.

Coutlhard said paved runways could be resurfaced at a fraction of the cost of traditional methods, with machines grinding the old pavement on site, mixing in PennzSupress, and reapplying the material, which hardens into a long-lasting surface.

The petroleum-based resin is delivered in concentrated form, the wax suspended in an emulsion designed to be diluted with water and applied. As the water dries, resin left behind binds with soil, gravel, and whatever other material is present.

Coulthard said BNSF Railway has purchased the product in bulk for dust-suppression use at terminals, and the U.S. Forest Service will be another major customer: “It will be included in the U.S. Forest Service road treatment program,” Coulthard said.

Coulthard expects the FAA and state agencies will approve PennzSupress for runway applications, given the combination of cost savings and extensive research and testing already conducted.