The Alaska Department of Transportation and Public Facilities has adjusted some of its winter road care methods to keep motorists safe more efficiently.
For the last few years, the department has used a salt brine, a mixture of sodium chloride and water, to prevent and tackle ice and snow on roadways in addition to the standard salt and sand.
“This is something that we use every year, not just during these circumstances,” said Jill Reese, special assistant to the director and media liaison for the department’s central region. “It just makes the roads safer any under conditions.”
As material costs continue to rise, using salt and sand exclusively to improve winter road conditions has become expensive. The cost of salt, sand and chemicals rose from more than $3,600 to just over $5,350 from the 2007-08 to 2011-12 winter season, according to a 2012 “Emerging Practices in Winter Highway Maintenance” report by the department.
One of the brine’s biggest advantages is that it reduces the amount of total sand the department has to use by around 30 percent, said Carl High, the superintendent for the Kenai Peninsula District.
“We’re putting out probably the same amount of salt, it’s just in a different form,” he said.
The brine mixture results in an approximately 23 percent solution of salt. To decrease potential erosion effects of the salt, the brine is sometimes enhanced with organic additives, High said. Referred to as “boosts,” the additives are plant-based, sometimes made from beets.
If the boost has a calcium chloride component, it also helps lower the temperature at which the brine will work, allowing it to stay on the roads longer, High said.
The organic additives are purchased out of state, though the DOT is searching for an in-state option, High said. One potential lead that was looked into was a vodka distillery that produced the organic matter as by-product, he said.
The brine can be used in three capacities: to prevent snow and ice on roads, to remove them from roads and to make plain sand more effective. As a preventative measure, the brine is sprayed on a road before bad weather rolls in, which prevents snow from packing, High said. He compared spreading the brine to coating a pan with cooking spray, so that whatever goes on top of it can be taken off more easily later.
“We use it in an anti-icing configuration or strategy,” he said. “We actually go out an apply it to the road ahead of the storm. … It helps us put it out in a more even, consistent distribution.”
The salt mixture put on top of existing snow or ice helps plows break it up more easily when they go through, High said. DOT workers also inject their regular sand with the brine in an act called pre-wetting, which helps the sand stay put on the roads and sink into the snow and ice, he said.
Sand is somewhat costly in that it has to be distributed each winter and cleaned up each spring, especially in more urban areas, High said. Some places in the Lower 48 have stopped using it altogether, he said.
Salt brine is produced in Soldotna, Crown Point and the Homer/Anchor Point area, High said, along with several other locations statewide.
“We produce brine at those locations and then we truck brine to some of the smaller camps, and they can use it to pre-wet,” he said.
Since the brine is made in Soldotna, it is used to service Kenai as well, High said.
As far as environmental concerns go, High said the brine is no more harmful than the salt the department already uses. Though he has gotten calls from people worried about animals being attracted to the sides of roads by the salt, High said he has never witnessed that.
Though the brine is a somewhat recent change to the way roads are cared for in Alaska, it has been used in the Lower 48 for years, according to an explanatory video on DOT’s website.
“This is just something that we’ve added as a tool in our toolbox over the years just to be more effective,” Reese said.
Reach Megan Pacer at firstname.lastname@example.org.