Chemical deicers and snowplows are commonly used in winter to eliminate hazardous ice and snow from parking decks and structures. While deicers are doing their job melting away snow and ice, some may actually be corroding the parking structure’s concrete and reinforcing steel, and some snow removal techniques may actually be doing more damage than good.
Here several tips to minimize unnecessary damage to parking structures during the winter months, and keep drivers safe.
Snow Removal Tips
Clearly mark expansion joints in a way that will be visible to the equipment operator when the deck is covered with snow.
Establish a snow removal pattern so that the plow blade approaches expansion joints, control joints and tee to tee joints at an angle no greater than 75 degrees.
Equip snowplow blades and bucket loaders with shoes or rubber guards that prevent direct contact with the deck surface.
Do not pile snow on the deck surface. Piles of snow can exceed the rated load capacity and cause cracking in the concrete deck surface.
Deicing/Salting Tips
Using chemical deicers to control ice and snow buildup is common. However, these chemicals can have a negative effect on concrete and reinforcing steel and should be used sparingly. There are several different types of deicers on the market that can be used, however, only those approved by the American Concrete Institute are recommended.
Sodium Chloride(road salt, table salt)
This is the most commonly used salt deicer. It has little effect on concrete but promotes corrosion in reinforcing steel and other metals. The use of this type of deicer is NOT recommended.
Calcium Chloride
This is a major ingredient in most commercial deicers. It has little effect on concrete but promotes corrosion in reinforcing steel and other metals. The use of this type of deicer is NOT recommended.
Ammonium Nitrate or Ammonium Sulfate
Use of this deicer will lead to serious concrete deterioration due to its direct chemical attack on reinforcing steel. Use of this type of deicer is NOT recommended.
Calcium Magnesium Acetate (CMA)
The effects of this deicer are similar to salt, but it requires more time to melt ice. It has no adverse effects on concrete or steel reinforcement. If a deicer is required, a CMA is recommended.
It is important to minimize the amount of deicing chemicals applied during the first two years of the concrete being laiod or poured. During this time, the concrete has an increased permeability which can allow the deicing chemicals to migrate into the concrete more rapidly. As concrete ages and cures, it will become less permeable and chemicals can not penetrate as easily.
It is important to remember that the use of deicing chemicals in general are not recommended. The safest way to remove ice and snow is to use a plow. Sand can also be used to increase tire traction on the deck, but be sure to protect the drainage system when washing down the deck after its use.