Is Salt Harmful to Concrete Driveways?

About Concrete

• Concrete is a durable paving material made of cement, aggregates and water. Though it is a durable and cost-effective construction material with many uses, its composition makes it vulnerable to some chemical compounds, as well as hard wear. Avoid using road salt the first year after your driveway's construction. New concrete is particularly susceptible to the effects of deicers such as rock salt. If you must use some material for traction on slick driveways, choose coarse sand, according to the ConcreteNetwork site.

Rock Salt

• Rock salt, also called road salt, is a compound made of sodium and chloride, just like ordinary table salt. It is simply a larger collection of crystals. This larger form of salt is spread on roads to melt the ice to create safer driving conditions in bad weather. The salt lowers the freezing point of the snow, preventing it from becoming a frozen hazard. Rock salt is one of the most inexpensive deicers on the market and is used for many applications, including for deicing residential driveways.

Harmful Effects of Rock Salt

• Rock salt, though inexpensive and easy to use, is a toxic chemical for the environment and can harm plants near sidewalks and driveways. As the salt melts, it enters the concrete. When it refreezes, it can separate the materials within the concrete. Road salt also holds water, causing the concrete to hold more moisture than it ordinarily would. As the water freezes, the pressure of the ice crystals can cause the concrete material to fail.

Salt Alternatives

• Other deicing agents are available for homeowners besides sodium chloride. Calcium chloride is chemical that gives off heat when applied and can be used at lower temperatures. It is generally more expensive than sodium chloride. Potassium chloride is sometimes used, but this compound can leave a residue that is harmful to nearby plants, according to University of Nebraska at Lincoln specialists Jay B. Fitzgerald and Donald E. Janssen. Urea is made from ammonia and carbon dioxide. It is sometimes used as a driveway deicer. Ammonia-containing products can degrade concrete surfaces, however. Calcium magnesium acetate is a salt-free melting agent used on bridges or other metal surfaces where salt corrosion is a problem.