Dear Tim,
My husband and I just recently moved into a new home and had a concrete driveway poured in December. Since then, we have had a terrible stretch of winter weather in the last couple of weeks. Our builder advised us not to use rock salt on the driveway. We instead used a salt substitute that claimed to be safe for concrete. However, we noticed the concrete appears to be flaking in a few spots. Is this due to the de-icer or do you think there is another cause? If we did damage the concrete, is there anything that can be done to avoid further damage or is it too late??
Sincerely,
Mary L.
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Mary,
It is very possible the salt hurt your driveway. In most cases, deicing salts will not hurt concrete that has been installed correctly. But your concrete could not have been installed at a worse time! Concrete installed in cold weather can suffer frost damage if it is not cured under insulated blankets. If the concrete got cold too quickly, the hydration process could have stopped or slowed to a crawl.
Concrete placed late in the season also can retain lots of moisture. This can freeze and pop the surface under the right conditions. The salt you installed can increase the freeze-thaw cycles. You need to go to my website and read many, if not all, of my past concrete columns. If you do have to repair the damge, be sure to read the concrete overlay column.
Tim Carter
www.askthebuilder.com
W3ATB