Why Is Salt Used to Melt Ice on the Roads in Winter?

Why Is Salt Used to Melt Ice on the Roads in Winter?

 

Why Is Salt Used to Melt Ice on the Roads in Winter?

 Why Is Salt Used to Melt Ice on the Roads in Winter?



Ice forms when the­ temperature of water reaches 32 degrees Fahrenheit (0 degrees Celsius), and that includes ice on roadways. Road salt works by lowering the freezing point of water via a process called freezing point depression. The freezing point of the water is lowered once the salt is added, so it the salt makes it more difficult for water to freeze. A 10-percent salt solution freezes at 20 degrees Fahrenheit (-6 Celsius), and a 20-percent solution freezes at 2 degrees Fahrenheit (-16 Celsius).
The key is, there has to be at least a tiny bit of water on the road for freezing point depression to work. That's why you often see trucks pre-treat roads with a brine solution (a mixture of salt and water) when ice and snow is forecast. If the roads are dry and the DOT simply puts down road salt, it likely won't make much of a difference. But pre-treating with a brine solution can help ice from ever forming, and will help reduce the amount of road salt trucks will need to spread to de-ice later.




Why Is Salt Used to Melt Ice on the Roads in Winter?

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