When winter rolls around and the snow piles up, throwing down some deicing salt can be tempting to keep your driveway and sidewalks safe and dry. But should you think twice before putting salt on your concrete surfaces?
The answer is that yes, salt does damage concrete. Over time, it can cause crumbling, flaking, cracking, and other undesirable long-term effects.
This article will explore why salt is harmful to use on concrete, ways to help prevent damage to the surface of your concrete, and some common alternatives to salt.
When salt (sodium chloride) touches concrete, the difference in pH between the two causes the chemical bonds within the concrete to break down. As the salt melts and mixes with the snow and ice, it gets absorbed by the concrete’s pores and deteriorates it from the inside.
This corrosion compounds over time. As more and more of the concrete’s pores are exposed and able to absorb the salty water, more and more deterioration can take place.
This is intensified by the many freeze-thaw cycles that happen throughout winter. As more concrete is exposed to water, the more likely it is to crumble or crack as the water expands when frozen, then thaws and repeats the cycle.
Salt is also only effective down to around 15 degrees Fahrenheit, meaning that when it gets colder than that, the melted ice can refreeze, causing slippery conditions and more damage due to expanding ice.
Here are some ways to help prevent damage to your concrete’s surface:
- Use non-chemical alternatives to salt to add traction to the surface, like cat litter or sand
- Keep up with maintenance and ensure your concrete is sealed with a high-quality penetrating sealer
- If you do have to use salt, remove any excess after the concrete is dry to reduce the amount of salt making its way into the pores
The best way to keep your concrete free of damage in the wintertime is to use deicers as little as possible, and make sure your concrete is sealed. Sealing your concrete won't eliminate the problems that salt can cause, but it can help slow down the rate of damage if salt is used.
No one wants an icy driveway or sidewalk full of slip hazards. Luckily there are alternatives to salt.
Chemical alternatives to salt
There are a few chemical alternatives to salt that are commonly used to deice concrete, but it is possible that they can also cause damage.
Calcium chloride is one of the most popular alternatives to salt (sodium chloride) for preventing slippery conditions. It stays effective at very low temperatures, down to around minus 25 degrees Fahrenheit, which means it will continue to melt ice at much colder temperatures than regular salt.
Magnesium chloride is a similar alternative to calcium chloride, but it doesn’t stay effective at temperatures quite as low. It is also more expensive, and it requires more material to de-ice properly, as it comes as a diluted solution.
Other alternatives to salt
To help reduce the likelihood of damage to your concrete, using alternatives that avoid salt and other chemicals is a better option.
Heated concrete or mats
Another method to avoid slip hazards in the wintertime is installing heating systems within the concrete itself. While expensive, they eliminate the need for wintertime chores like shoveling snow and worrying about deicers damaging your concrete.
If installing a heating system in your concrete sounds like too big a task, you can also try heating pads that plug into an outdoor outlet and melt the snow and ice where they’re placed.
Natural traction enhancers
Rather than melting the snow itself, you can put materials down on top of snow or ice to improve traction. There are many natural options you can use that you likely already have in your house or garage, like coffee grounds, cat litter, wood chips, and sand, for example.
Now that you’ve learned about how salt can negatively affect your concrete, you’re ready to use alternatives, like the heated concrete pads or traction enhancers, and ensure that your concrete is sealed and ready for winter.
Want to learn more about concrete? Check out the following articles from our Learning Center:
- Concrete Cleaning & Sealing
- How does winter affect concrete?
- Concrete Grinding vs. Replacement vs. Leveling