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How REALLY bad is Calcium Chloride for concrete ?

PaulSC's Avatar

Join Date: Jan 2015
Posts: 362

12-15-17, 06:52 PM   #1 (permalink)  
How REALLY bad is Calcium Chloride for concrete ?

I had a new concrete sidewalk and driveway put this Summer....the guy told me NOT to use salt as it damages the concrete and yes - I have heard that before and I know it makes sense, however, I am wondering....is there such a thing as a safe level of calcium chloride?
If I am using it only 2-4 times during a winter for really tricky conditions and not all the time after every snow fall....would that still have an impact ??

Also, it is my understanding that Calcium salt is a bit more gentle than some other ones....


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XSleeper's Avatar
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12-15-17, 07:06 PM   #2 (permalink)  
It is extra harsh on new concrete.

If you use it VERY sparingly it will be okay, but if you put so much salt on that it remains on the sidewalk after it has melted the snow and ice... that is what's going to damage it the most.

I spread it by hand like scattering seed... very lightly.

Tony P.'s Avatar

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12-16-17, 04:48 AM   #3 (permalink)  
Calcium chloride won't damage concrete in minutes or a few hours. Once the ice is melted try to sweep off any excess ice melt.

Norm201's Avatar

Join Date: Sep 2013
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12-16-17, 07:34 AM   #5 (permalink)  
I get this question almost daily during the winter months.

My stock answer...Salt in of itself will NOT harm concrete! You can set a block or layer of salt on concrete and let it set forever and no harm will take place! BUT... liquids will seep into the crevices and cracks (even microscopic cracks) and when that liquid freezes, it expands and pops out concrete pieces. So the problem is not to let liquid freeze! The way to do that is use a salt that keeps liquid (water) in a liquid state at as low a temperature for as long a time as possible! This is called the freeze thaw cycle. So which salt will prolong the thaw cycle? Ordinary rack salt can provide liquid state to about 25 degrees F. Beyond (or below that temp) you want to use other salts. Price will dictate ability to maintain liquid.

Potassium chloride, rock salt, magnesium chloride and calcium chloride are the most common ice-melting salts used today.

So my words of wisdom is as follows...Choose the salt that will give you a safety factor and not damage your concrete.

I lifted the following info from various Internet sites so I won't bother to ref the sources.
Comparing Temperature Ranges

The first measure of an ice melter’s effectiveness is the range of temperatures in which it can provide deicing action (in a reasonable time period). The “practical” lowest temperature limits for these materials is defined as effective within 15-20 minutes of application and is listed next to the material. When reviewing deicing materials on the basis of their effectiveness at practical temperatures, they rank as follows:
  1. Calcium Chloride (-25o F)
  2. Magnesium Chloride (5o F)
  3. Sodium Acetate (5o F)
  4. Calcium Magnesium Acetate (5oF)
  5. Potassium Chloride (12o F)
  6. Urea (15o F)
  7. Sodium Chloride (20-22o F)
  8. Various Blends (usually 20-22o F)

Many are concerned with deicers’ effects on concrete. Among the materials under review, only ammonium sulfate and ammonium nitrate will chemically attack concrete. The others do not chemically attack concrete, but can affect the freezing point of water. When the freezing point of water is depressed, the number of freeze-thaw cycles the water goes through can increase. And the expansion of freezing water (hydraulic pressure) can exceed the strength limits of the concrete. Spalling can be the result, but this is greatly minimized in good quality air-entrained concrete.

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