Can De-Icing Salt Damage Your Concrete?

With the arrival of winter, many homeowners begin putting de-icing salt on their sidewalks. Although de-icing salt is important for providing safe passage over walkways and driveways, it can also be damaging to many man-made structures and possessions. If you are in the habit of heavily de-icing your walkways, you may have wondered in the past whether or not this practice can damage your concrete. Knowing the answer will help you protect your your sidewalks and driveway this winter.

Can de-icing salt damage your concrete?

Under certain circumstances, yes, de-icing salt can damage your concrete. Concrete is a porous material and salt is hygroscopic, meaning that it attracts water. When salt is laid over concrete, the concrete absorbs more water than normal. During freeze-thaw cycles, the water inside the concrete freezes and expands, causing the top layer of concrete to pop off. This condition is known as spalling.

Why does some concrete become damaged and other concrete does not?

Concrete is most susceptible to damage from de-icing salt in the first 30 days after the concrete dries, because freshly laid concrete already has a high water content. In addition, concrete that is thinned with water at the time of pouring will not be as strong as concrete that is properly installed. If the concrete was thinned during installation, this means that the concrete will not be able to withstand the damaging effect of rock salt in the winter.

If your concrete has become spalled because of de-icing salt, what can you do?

If the spalling is minor, you may either choose to live with the spalling or have a paving company patch your concrete. If the entire surface of the concrete is badly spalled, talk to a paving company about getting the walkway resurfaced.

If your old walkway was damaged by rock salt and you're thinking about resurfacing it, how can you prevent the same thing from happening again?

Once the new walkway is poured, use sand on the concrete instead of salt during the first winter. Although sand will not melt the ice, it will provide traction on the ground that will prevent people from slipping.

It's also important to choose a reputable paving company. If your paving contractor uses best practices during installation, your walkway can last for many years without trouble. As you choose a paving company, each company what the compressive strength of the concrete will be. The minimum compressive strength for withstanding de-icing salt is approximately 4,000 pounds.

Following these tips, you should be able to protect your walkway this winter and avoid issues with spalling.  

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