Calcium Chloride vs Rock Salt

If you have maintained a property in an area that snows in winter, you probably asked this question before. What are the differences between calcium chloride and rock salt? This article will explain the differences for you.

What is Rock Salt?

Rock Salt is one of the common names for sodium chloride. Food grade sodium chloride is also known as table salt. Rock salt comes from salt mines or evaporating sea water. When combined with water, rock salt solution has a freezing point of 14 °F, much lower than water without salt. Because of this affect, spraying roads with rock salt before snowfall keeps the snow from sticking and keeps ice from forming.

What are the pros and cons of Rock Salt?

Pros:

  • Rock salt is cheap. You can buy large quantities with not very much money.

Cons:

  • Rock salt doesn’t work when temperatures drop below 14 °F.
  • Rock salt also damages surfaces like wood and concrete. For wood surface, it reduces moisture in the wood and causes cracking. It reacts chemically with cement to leach out certain compounds needed for strength.

What is Calcium Chloride?

Calcium chloride is commonly called: calcium chloride. That's right. It does not really have a common name, which is why people are less familiar with it. It is usually used for ice melting. It does not occur in large quantities on its own, but can be produced from a simple chemistry process . Worldwide production is under 5 million tons. When combined with water, calcium chloride keeps solutions from freezing at as low as -62 °F. Also, calcium chloride releases water when the solid prills gets absorbed into water.

What are the Pros and Cons of Calcium Chloride?

Pros:

  • Calcium chloride works down to extremely low temperatures
  • Calcium chloride way less impactful to concrete than rock salt

Cons:

  • Calcium chloride is more than twice as expensive as rock salt, although still within manageable range

Goal of De-icing

When it comes to de-icing, property owners' and contractors' primary goal is to eliminate pedestrian exposure to icy surfaces. To keeping sidewalks safe under all conditions, we should compare the lowest effective temperature of calcium chloride and rock salt and choose one that is effective at the coldest temperatures you are likely to experience. Calcium chloride stands apart  maintaining ice melting power down to -25°F (-32°C). On the other hand rock salt begin losing effectiveness at 14°F (-7°C).

Summary

Both rock salt and calcium chloride can be used on top of existing ice. With the help of some simple ice removal tools, you can soon have your sidewalks and walkways passable. However, because of the pros and cons above, compared to other common deicers, calcium chloride provides the optimum combination of deicing properties for sidewalk winter maintenance. For better results, try applying the salt before it snows. Check out this article for the comparison of applying calcium chloride before and after snow (When Should I Salt My Driveway? Before Snow v.s After Snow). This can prevent ice from sticking to driveways or other surfaces and greatly reduce the work load after snowing. So those are the reasons why rock salt is getting less preferable and calcium chloride as the premium alternative is getting more and more popular.

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