Concrete which has been damaged by cold weather commonly has surface defects. The most common defect is spalling. Spalling is simply the peeling or loss of the top finished layer of the concrete. It usually happens because the upper surface of the concrete froze before enough crystals grew to give this layer strength of at least 500 psi.
Popouts are another common surface defect. A popout is created when a piece of aggregate (rock) in the upper surface of the concrete explodes as a result of freezing. Some pieces of aggregate have a tendency to absorb water. This water freezes, expands and eventually causes a tiny explosion. Gravel companies go to great lengths to try to remove this type of rock from the gravel – but they don’t always catch every piece.
De-icing salt damage is another common surface defect. Scaling of your concrete can occur even if everything was done correctly. Here’s what happens: As concrete is exposed to air, it gets harder. That process is called carbonation. The carbon dioxide in the air reacts with the concrete and creates limestone (calcium carbonate). This carbonation process, however, usually takes one year to produce any substantial differences in strength. So, if you use de-icing salts or they drip from the under side of your car onto your new slab, you may have a problem with de-icing salt damage.
The #1 temperature related issue is weakened & cracked concrete.
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The ideal temperature range for concrete curing is from 65 to 85°F for seven days. If your concrete isn’t cured within that temperature range, some of the above defects can and will occur. Simply using insulated blankets or straw to protect concrete isn’t enough, especially if temperatures dip below 40°F. (In fact, if the temperature is below 14°F, not only will it not set, but it will also freeze.)
Powerblanket® heated concrete curing blankets maintain the ideal temperature range. They’re an easy, inexpensive way to protect your investment – and just as importantly, allow your construction project to continue quickly regardless of the weather.