New Approach to Road Salt
NOTE: The following feature story was written by Steve Smith.
It's been a trying winter for road maintenance around Nova Scotia. Temperatures dancing above and below the freezing mark are making it difficult for snowfighters at the Department of Transportation and Infrastructure Renewal to know what tool to use to keep roads safe for drivers.
In Antigonish County, the department is studying a new tool that may jump-start the melting process and make it easier to clear snowy roads faster. The department is testing a liquid anti-icing process that, if successful, could save money and improve road safety.
Anti-icing treatment involves spraying salt-brine solution directly onto the road surface. When the water evaporates, a fine residue of salt is left behind. If applied before a storm, the salt residue prevents snow and ice from bonding to the road.
"It's the same as snow on your driveway," says Paul Colton, the department's area manager. "If you drive your car over the snow before you shovel, you find the snow that was pressed down by your tires is harder to remove because it has bonded with the pavement."
The anti-icing treatment stops that bond from forming and makes the road easier to clear. Anti-icing technology is used in other jurisdictions in North America, but is fairly new to Nova Scotia.
To make the proper solution, rock salt is added to water until 23 per cent salinity is obtained. The solution is then poured into a 4,000 litre water tank that the Antigonish staff attached to the back of a retired salt truck.
For the rest of the winter-driving season, the truck, displaying a large anti-icing sign on the back, will be using the solution on Trunk 4 between Brierly Brook and the Pictou County line, if bad weather is on the way.
"Timing of the anti-icing application is the key to having it work well," says Colton. "We like to get it on the surface eight to 24 hours before a storm, and at a temperature not colder than -5 C."
He says the department's system of road and weather monitoring stations provide valuable assistance in making the right decision.
"It's definitely helpful to have those modern tools," says Colton.
By getting the road surface treated proactively, Nova Scotia's snowfighters can help clear the road faster and make it safer. Also, the anti-icing mixture doesn't bounce or blow off the road when applied, so it can be used more efficiently.
Colton says other jurisdictions have reported savings of up to 15 per cent for anti-icing applications, when compared with normal salt use.
He says his staff will be monitoring road conditions carefully and recording results.
"If it works like they say, we could be adding this process to our toolbox for snow and ice control, not only here but around the province."