Back in May, a Boeing 737-200 made Canadian news after taking its final voyage to Cambridge Bay. What made the plane, nicknamed “Spirit of Yellowknife,” so special was its ability to land on gravel runways. The Canadian North aircraft received modifications from a special Boeing kit to make it compatible with operation on gravel runways while its destination airports remained vigilant about their gravel runway surface maintenance.
These kits are essential additions to aircraft meant to perform on gravel surfaces. Unlike typical asphalt airstrips, gravel opens the possibility for small rocks and debris to make their way, and ultimately damage, the mechanics of the plane. Gravel runway surface maintenance is crucial in limiting potential damage.
To some, this commemoration for a plane might seem bizarre, but for those who live in isolated areas, it isn’t so fanciful. In remote areas of Alaska and Canada, gravel runways play a pivotal role, allowing delivery, and often the only source for delivery, of necessities like food, industrial materials, medicine, medivac services as well as passengers, to their distant villages.
Gravel runways are the lifeblood of these remote villages and communities. Alaskan villages and Canadian communities range from as few as 12 to hundreds of residents, all of whom depend on the service of gravel runways to survive.
There are 9 distresses common to all these runways, those with Boeing jet traffic and those with single engine piper traffic. These runways are exposed to very harsh weather, making regular gravel runway surface maintenance critical.
Along with the brutal weather, it may seem surprising to learn that the predominant issue facing the surface maintenance of gravel runways is perhaps the one resource that’s always assumed to be beneficial: water. However, that’s a myth as old as the first gravel runway.
How freeze/thaw cycles put your gravel runway surface maintenance in hot water
These rougher weather conditions become very problematic for places that experience high levels of precipitation mixed with freezing temperatures. For northern regions, this phenomenon happens continuously throughout the long winter months in what is known as freeze/thaw cycles.
Freeze/thaw cycles occur when water reaches the surface of the runway and fills in pockets of the aggregate. Just as the temperature meets 32° Fahrenheit or below, the water subsequently freezes inside the gravel runways. When it freezes, moving from liquid to solid form, the water enlarges by about 9%. The water’s increased surface area places pressure on the aggregate by pushing beyond the bounds of the cavity. After the temperature rises above the freezing point, the ice melts back into liquid form, but the gravel remains overly expanded, breaking its constructed shape.
While the water remains unaltered between form changes, the same cannot be said for gravel runways.
Once the water melts, runways can experience drastic shifts in quality, with deterioration that makes it unsafe for landings. Perhaps the most common visible difference after a series of freeze/thaw cycles is expansion and contraction damage seen in the form of cracks, potholes, soft spots, and water pooling divots.
However, your runway could experience more than just visible deterioration. The stress induced by the water can reduce the bearing strength of gravel runways, stripping stabilizers as well as dust palliatives. A combination of base course destabilization and surface level erosion can then dislodge aggregate and loosen unbound fines. This results in decreased operational quality, the presence of harmful FOD on the surface and increased dust emissions.
The constant waxing and waning in temperature, alongside increased precipitation, leaves these gravel runways vulnerable to an overall shortened service life, which can be harmful to these regions that rely on this form of transport for life or work. Effective gravel runway surface maintenance demands a proven solution that can resist the harmful impacts of water.
Fight the Enemy with Midwest’s EK35
To us, water is essential to life. We use it every day for drinking, cleaning, and cooking. Likewise, industries need it for processing, diluting, cooling, and other manufacturing tasks. Yet when it comes to gravel runways, water is the enemy.
Here at Midwest, we’ve always understood the enemy. Backed entirely by science, products like EK35 are honed to defend your gravel runways against the destructive effects of water.
EK35 is a surface stabilization solution that can be applied topically onto a prepared gravel runway surface (Fines Preservation) or constructed into the upper 4-6” of the runway (SECUR). EK35 works by forming permanent bonds between itself and the runway surface aggregate. Once EK35 has chemically reacted with the aggregate, the treated particles are locked in place at the runway surface, preventing the occurrence of aggregate segregation, loss of material, FOD, dust generation, and other negative surface distresses.
One attribute that makes EK35 an effective, long-term runway stabilizer is its ability to repel water and prevent moisture infiltration. EK35’s binding quality repels water, forcing it to drain away rather than within the runway. As a result, EK35 system enhances and maintains the runway CBR values even when gravel runways encounter extreme amounts of moisture. Due to its water insolubility, EK35 has been proven to not be removed or washed away by prolonged exposure to high water moisture levels.
EK35’s role as an effective method for sustaining the performance of gravel runways during freeze/thaw cycles has been proven by science. In an independent study conducted by the Norwegian University of Science and Technology, the team concluded that EK35 provides “a promising solution…in cold regions.” For more details about the researcher’s findings, you can check out our “Water is the Enemy” video.
You can’t help your geography, but that doesn’t mean you have to endure the constant surface maintenance and concern of regressing gravel runways. When you partner with Midwest to implement our gravel runway program, you no longer have to worry about the health of your gravel runways. Whether rain, sleet, snow, or shine, you can trust that your runways are shielded from the damaging effects of water so you can keep critical life air traffic flying in and out of your airport.
For more information on Midwest’s dust control and gravel runway surface maintenance solutions, contact us today.