Additives to reduce chemicals' corrosive properties are also being used. Currently these alternative materials are more expensive, but can be useful in special situations. De-icing chemicals work by lowering the freezing point of water. These low freezing points are what makes salt and calcium chloride useful. Before a dry de-icing chemical can act it must dissolve into a brine solution.
Calcium chloride has the ability to attract moisture directly from the air.
Changing ice or snow into water requires heat from the air, the sun, the pavement, or traffic friction. Even when the pavement is below freezing, it holds some heat and can help melt snow and ice. Factors affecting de-icing action Chemical concentration, time, pavement temperatures, weather conditions, type of road surface, topography, traffic volume, width of application, and, most importantly, time of chemical application all affect the process of melting snow and ice. If too much chemical is used, not all of it will dissolve into solution and some will be wasted. Too little chemical may not sufficiently lower the solution's freezing point.