Rock Salt Damage

Rock Salt Damage

The most damaging thing that can be done to concrete is to apply rock salt to the surface during icy conditions.

Here's how the damage happens: As we all remember from our grade school science classes fresh water freezes at 32°F, salt water at zero. To change state from a solid to liquid water must absorb energy. Additionally water is one of the few compounds that expands when it freezes.

By putting rock salt on ice you are forcing the ice to become salt water and change its state to a liquid. To do so it must absorb energy and most of that comes from what it is touching which is the concrete.

As the concrete gives up its energy the concrete becomes colder freezing the freshwater encapsulated in the surface. As the freshwater encapsulated in the surface freezes it expands breaking off a small area.

This process can be repeated redundantly as the ambient temperature fluctuates and/or more salt is applied or dissolves.

Deicer Damage Example

Deicer Damage

Wherever a sodium product is used as a deicer this random pot mark damage occurs as the freezing freshwater that is encapsulated in the concrete surface expands pushing against the underlying rock in the concrete.

The embedded rock in the concrete is nonporous and does not allow the freezing freshwater to expand in surrounding capillary voids as it does were rocks are not present.

View Some Other Examples