To understand how salts work to melt ice, you need to first understand water and ice. Water is a low viscosity liquid and its molecules are randomly organized and flow freely at room temperature.
As temperatures lower, water molecules slow down and stick together forming ice. The ice forms at a temperature of 32 F or below.
To stop the ice from forming, you need to add a dissimilar substance to the water. For example, by adding oil, water will not freeze at its normal freezing temperature. Ice melts are also dissimilar in structure to water and will lower the freezing temperature of water.
How does salt work? salt may be applied on a dry pavement, but it does not begin working until moisture is present for the salt to dissolve into a brine.
The brine will not freeze until the air temperature reaches the brine’s eutectic temperature.
When spread on snow or ice, salt makes a brine immediately with the film of surface water on the ice and snow. This lowers the freezing point and starts melting the ice that the brine is in contact with.
Maintaining safe pavements this winter
Garden State Sealing