With the onset of winter, managers must strive to minimize damage to structures. November 18, 2022
Winter is just around the corner. In many parts of the country, that means dealing with snow and ice conditions from December through March. Facility managers should already have plans in place to manage the roads and sidewalks of their institutional and commercial facilities. But in case they’re still working on their programs, Western Specialty Contractors offers managers tips for minimizing damage to parking structures during the winter months.
Chemical de-icers and snowplows are commonly used in the winter to remove dangerous ice and snow from patios and parking structures. While de-icers melt snow and ice, some can actually corrode the concrete and reinforcing steel of the parking structure, and some snow removal techniques can actually do more damage than good.
When clearing snow from parking structures, managers should consider the following actions:
- Clearly mark expansion joints in a manner that will be visible to the equipment operator when the deck is covered in 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 plow blades and bucket loaders with rubber shoes or guards that prevent direct contact with the deck surface.
- Do not pile snow on the deck surface. Snow piles can exceed the rated load capacity and cause cracks in the surface of the concrete deck.
Defrosting and Salting Tips
The use of chemical de-icers 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 types of de-icers 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 de-icer. It has little effect on concrete, but promotes corrosion of reinforcing steel and other metals. The use of this type of defroster is not recommended.
- Calcium chloride – It is a major ingredient in most commercial de-icers. It has little effect on concrete, but promotes corrosion of reinforcing steel and other metals. The use of this type of defroster is not recommended.
- Ammonium nitrate or ammonium sulphate – Use of this de-icer will cause severe concrete deterioration due to its direct chemical attack on the reinforcing steel. The use of this type of defroster is not recommended.
- Calcium Magnesium Acetate (CMA) – The effects of this de-icer are similar to those of salt, but it takes longer to melt the ice. It has no adverse effect on concrete or steel reinforcement. If a defroster is required, a CMA is recommended.
It is important to minimize the amount of de-icing chemical applied during the first two years of concrete installation. Meanwhile, the concrete has increased permeability which can allow de-icing chemicals to migrate into the concrete more quickly. As concrete ages and hardens, it will become less permeable and chemicals will not penetrate as easily.
De-icing chemicals in general are not recommended. The safest way to remove ice and snow is to use a snowplow. Sand can also be used to increase tire traction on the deck, but be sure to protect the drainage system when washing the deck after use.