How to Prevent De-Icing Salt from Damaging Concrete In Winter
by TRP Ready Mix on January 11, 2019
Concrete Suppliers Offer Tips to Help Keep Your Concrete in Good Condition during the Winter
Winter is here, and winter weather means plenty of salt dumped on roads and driveways. That salt can damage concrete, especially if it’s new. If your concrete is not mixed, installed, sealed, or cured properly, it’s at risk of being weaker and more susceptible to damage in winter from below-freezing temperatures and de-icing salts. Simply put, it’s never been more important to invest in a concrete sealer and other protective products!
De-icing salts exacerbate the effects of the freeze-thaw cycle on concrete, making concrete more prone to cracking. And come spring, cracked concrete means you’ll have to spend more money to repair or replace your concrete.
So the best thing you can do to protect your concrete and your investment during the harsh winter—and save your money come spring—is to ensure you have quality concrete from reliable and experienced concrete suppliers and understand these causes of winter damage and how you can prevent it.
How De-Icing Salt Damages Concrete
Concrete is like a stiff sponge that absorbs water. And if you add rock salt to ice and snow, it will form salt-water slush. As this slush melts, the concrete will absorb the water.
While this water absorption is fine on a warm summer day, winter temperatures drop well below freezing, causing the absorbed water to freeze and form ice crystals, which expand and eventually break the concrete. When water freezes, it expands nine percent and can exert up to 100,000 pounds per square inch (psi) of pressure.
While concrete absorbs water, salt attracts water. So the salt water absorbed by the concrete will lead to concrete holding more water, and eventually becoming saturated with water. As more water freezes in the concrete and the pressure from growing ice crystals increases, your concrete will become more damaged, with the surface likely to spall—peel, flake, or pop out.
Freshly poured concrete is the most susceptible to this damage since it is still highly saturated with water. If you poured concrete in the late fall, it will need a minimum of 30 days to dry.
The only way young concrete can withstand the below-freezing temperatures of winter is if your concrete suppliers added enough cement to the mix, and this cement was not diluted with water. Cement creates a hydration reaction that emits heat in the concrete, preventing it from freezing.
Sealing Concrete Before Winter
To prevent winter damage to your concrete, apply a concrete sealer before winter starts. And if winter has already started and you haven’t sealed your concrete yet, keep your eye out for a day when your concrete is dry and free of snow and ice so you can seal it before the worst of winter arrives.
A concrete sealer can prevent water absorption in concrete during the winter, thus preventing the devastating effects of the freeze-thaw cycle combined with de-icing salts. Concrete sealers with penetrating water repellants—such as silanes and siloxanes—create a hydrophobic (water-repelling) silicone barrier through a chemical reaction within the concrete.
These water-repelling sealers coat concrete pores and capillaries that are typically permeable to water. As a result, the silicone barrier prevents water absorption at the surface but still allows concrete to breathe—allowing water to evaporate from concrete.
These penetrating water repellants also prevent the absorption of chlorides—salts—that will damage concrete and corrode steel reinforcing rebar. And since silanes and siloxanes coat the pores and capillaries below the concrete’s surface, these sealers won’t change the appearance of concrete, reduce concrete’s slip resistance, or experience the same wear and tear as other sealers.
How to Prevent Damage to Concrete
The most important step you can take towards preventing winter damage to your concrete starts well before temperatures start to drop. Investing in high-quality concrete, from mixing to installation to sealant and curing, is worth it. Concrete suppliers can help you find the right mix for your concrete project.
Here are some suggestions for ensuring your concrete will be strong and able to withstand many winters without damage:
- Use concrete with a minimum compressive strength of 4,000 psi—the stronger, the better to withstand the force of expanding water.
- Use air-entrained concrete so water can enter the tiny entrained air voids, relieving pressure from concrete pores and capillaries when water freezes and expands.
- Don’t add water to the concrete mix at the work site.
- Use concrete sealer to prevent water absorption (but avoid foam-forming sealers).
- Get experienced workers to mix and pour concrete for you.
- Keep any drainage covers clear around concrete so rain and meltwater can properly drain throughout the winter instead of pooling up and sitting on concrete surfaces.
- Don’t plow snow on concrete using a metal blade—instead, use a rubber or vinyl-edged blade for snow removal.
- Don’t use metal shovels to shovel snow off concrete—use a plastic shovel instead.
- When snow blowing a concrete driveway, use a snow blower with plastic or vinyl shoes to protect the concrete.
- After parking your vehicle, remove excess snow build-up on your wheels or fallen snow from your wheel wells to prevent any accumulated de-icing salts from getting onto your driveway.
- Use sand instead of de-icing salts on your concrete in winter.
While high-quality concrete is at less risk of damage from de-icing salt, using sand is still a great option. Sand provides traction but doesn’t melt ice, making your walkways and driveways safer to walk on in slippery winter conditions.
Dealing with Damage in The Spring
The last thing you want to see on your concrete patio, walkway, or driveway is a flaky, cracked surface come spring. This problem is all too common for many homeowners after an especially tough winter with extreme cold and plenty of snow and ice storms.
Depending on the extent of the damage to your concrete, there are several ways to repair it come the spring. For superficial damage, such as spalling on the surface, you can have the loose, flaky material removed. And then you can apply an overlay.
Applying a thin cross-section for decorative concrete allows the pattern to show through an overlay. Stamped overlays also help repair stamped concrete.
Replace Badly Damaged Concrete
But if the damage is too deep to repair with an overlay—such as cracks below the surface—then you’ll need to remove and replace the damaged concrete. Full replacement isn’t ideal, but gives you a chance to be extra cautious and have quality concrete properly mixed, poured, cured, and sealed to prevent future winter damage.
When replacing concrete, keep in mind the tips above to ensure your concrete is strong enough to withstand winter damage. Concrete suppliers can help you choose strong products for your project. Keep an eye out for compressive strength and air entrainment properties to withstand the pressure of freezing water.
Concrete suppliers also have the experience and expertise to mix and pour concrete so it is of high quality. Applying water-repelling concrete sealer and avoiding de-icing salts gives you peace of mind. Rest easy knowing that winters will no longer take such a toll.
Whether you have a concrete driveway, walkway, or patio, prepare your concrete for winter. And take care of your concrete so it will last for many years (and winters) to come.