How it works
It may seem dangerous to add liquid to a road that might freeze, but this liquid can prevent snow from sticking to the road and prevent frost or black ice. Thanks to magnesium chloride, winter driving can be a safer experience. It's one of the best weapons to fight icy roads. This liquid works like antifreeze by lowering the freezing temperature of water and preventing ice from forming a strong bond to the road. It helps keep roads from becoming slick, improves safety and reduces accidents.
Safer to use than sand?
Environmental studies conducted in the 1980s showed magnesium chloride to be less toxic than baking soda or salt. Unlike sand, it won't crack your windshield or chip your car's paint, and tests have shown that the proper application of magnesium chloride produces no negative effects on ground water, surface water or vegetation.
In many cases, magnesium chloride works better than sand, as it keeps snow from firmly sticking to the pavement. Magnesium chloride also lasts longer than sand and works in a broader range of conditions. Sand can be crushed by traffic and produce airborne dust, which contributes to pollution. Because sand is easily blown off the road by traffic, it requires repeated applications.
When and how is magnesium chloride used on highways?
For anti-icing, a light application of the liquid is laid on a road before a storm to prevent a hard bond of ice, reduce snow buildup and speed snow and ice breakup after the storm. For de-icing, the liquid is applied to remove a thin layer of snowpack or ice already on the road. It can be very effective for melting black ice and freezing rain.
For pre-wetting, traditional sanding material is wet with magnesium chloride, causing sand to stick to snowpack better. Magnesium chloride can keep sand from blowing to the shoulder of the road.
Expensive to use?
Magnesium chloride is usually the most cost-effective alternative when considering the whole picture. There are less expensive chemicals to use for snow and ice control, such as salt and straight calcium chloride. But those alternatives can be harmful to vehicles, bridges and the environment. Magnesium chloride is a good alternative because it is less corrosive and works better than other chemicals. It reduces environmental impact, bridge corrosion and vehicle damage.
What about the future?
In the last few years, Colorado has been working to develop higher standards for a de-icer that is appropriate for our environment and less corrosive than other alternatives. One of these solutions incorporates corn by-products. However, some of the organic products eat oxygen, killing water life and allowing a higher concentration of salt to flow into the water supply. Research still is under way.