Winter weather conditions of any type are tough to deal with but are especially difficult when it comes to concrete. While it can be placed and poured in cold weather conditions, a variety of precautions must be taken to account for and alleviate the negative impacts of winter weather temperatures.
But, what exactly counts as winter weather concreting? As it currently stands, the American Concrete Institute (ACI) defines it as “a period when for more than three successive days in which the average daily air temperature drops below 40 degrees Fahrenheit, and stays below 50 degrees Fahrenheit for more than one-half of any 24 hour period.”
As anyone in the business can tell you, winter weather has significant potential to freeze concrete at an earlier stage than expected and can introduce a brand new set of problems.
Winter Weather and Its Affect on Concrete
Salt and Water Cause Cracks and Damage
For starters, we should discuss exactly how salt and water affect concrete because if concrete is pour while there is moisture or salt on the ground, you could be in trouble. Have you ever noticed that icy roads seem to look worse for wear after they dry up? Well, there is a reason for that.
Concrete is a permeable material which means as solid as it may look, liquids and gases can still pass through it. As water freezes and thaws on top and within the concrete, extra stress is placed on the chemical bonds that make up its solid state.
This is then further exasperated when salt and a variety of other de-icing chemicals are added and attract additional water and, in turn, increases the amount of water that gathers within the pores, allowing the acidic properties of salt to attack the bonds that hold the concrete together. All of these combinations mixed together intensifies deterioration at a molecular level.
Important Things to Know: Pouring Concrete in Winter Weather
Your contractor should make sure any and all concrete is reinforced with either steel rods or mesh as these have a higher tensile strength than the material itself and will help support the concrete and handle tension much better than the concrete will by itself.
After deciding where the concrete will be poured and it has been cleared of any ice and snow, be sure to thaw the ground for a couple of days, prior to pouring, using heat pipes, blankets, or electric blankets. Once the it has been poured, it must now be protected from freezing for the next 24 hours and/or until it has reached a minimum strength of 500 pounds per square inch (psi).
This step is extremely important in the process because if concrete freezes before it has developed sufficient strength to resist the expansive forces typically associated with the freezing water, ice may begin to form and could result in the disruption of the cement and cause an irreparable loss in strength, sometimes up to a 50% reduction in its ultimate strength.
Afterward, your contractor will remove any standing water with a squeegee or vacuum and then coat the entire area with a high-quality sealant. This coating will help repel water and any other chemicals that could potentially cause expansion or contraction as your newly poured concrete adjusts to the current temperature.
Next, your contractor will wrap up any corners, protrusions, and edges that could potentially freeze, including any protruding rebar. After about 72 hours, the wrapping will be removed to allow the concrete to air dry.
Catering to Your Needs Year Round
Here at KansasCityConcrete in Kansas City, we know what it takes to provide lasting results no matter what the temperature is. If you notice that your concrete is in need of repair, or needs to be replaced, don’t hesitate to contact us for a quote today!