Sodium chloride, more commonly known as salt, is used most commonly to deice a road during winter conditions. The salt used on roads is mined from rock salt, crushed and treated with anti-caking chemicals. The salt works by lowering the freezing temperature of water, melting the ice on the road with help from heat from the pavement, the sun and friction caused by traffic. Salt can have negative environmental impacts on the wildlife surrounding the salt-covered roads. It also negatively affects vehicles and water supplies. Damage to wildlife can reach as far as 60 feet from the treated road or bridge.
Calcium chloride is used to deice bridges and roads and acts eight times faster than salt. It is also less corrosive than salts used to deice bridges. Calcium chloride can deice roads in weather conditions reaching down to -59 degrees Fahrenheit, and it remains active longer than salt alone. This chemical also releases heat as it melts, enabling it to break bonds in the ice on roads. When used in combination with wetted salt, it dissolves around the salt to activate it and speed up the deicing process. Calcium chloride does not affect the environment as negatively as sodium chloride, and it does not create problems with sediment.
Calcium magnesium acetate is used on bridges to prevent snow and ice particles from bonding on the surface of the road. This chemical is applied to roads before a storm system comes through to prevent snow from sticking. If the snow sticks to the road, it is lighter and drier, which is important for improved traction. This also allows snow removal trucks to easily scrape the snow from the road. This chemical is less harmful to the environment than salt or sand, and it does not corrode vehicles or road surfaces. It is a biodegradable chemical that requires little cleanup once snow melts.
Sand is an abrasive material commonly combined with salt and other chemicals to improve the traction on bridges and roads. Sand is helpful when low temperatures render other chemical deicers unusable. Salt and sand combinations can speed up the corrosion of vehicles that come into contact with the deicing agents, and cleanup is often required on bridges and in urban areas. Sand can also cause sewage systems to clog and back up, and air pollution from particles that are less than 10 microns in size can occur if cleanup is not performed quickly enough.