Yesterday we talked about setting concrete forms and pouring the concrete to fill the void creating the concrete walls for your foundation.
Today I was going to go on and talk about what comes next, but we received several inquiries and comments about pouring concrete in bitter cold. Today let’s take a small tangent and see what can happen in the dead of winter.
As we all know here in New England we are in a snap of severe cold artic weather. This morning in Burlington it was -7 degrees and in other areas of Vermont it was significantly colder. Not only was it bitterly cold the wind was making it seem worse than it already was. It really was a nasty winter morning. And as I am writing this blog it is again below zero. ( By the way, how can it be less than nothing? Ever since I was a kid I’ve been perplexed by that weird notion. Oh well………………. )
“Winter Concrete” is a mix of Portland Cement, aggregate, and water. Did you know that Portland Cement was patented in England back in 1824 and it is a mixture of calcium, silicon, aluminum, and iron?
Winter Concrete is made by adding both HOT water and Calcium Chloride. Calcium Chloride is added to speed up the curing. Many people think that curing concrete happens as the water evaporates out of the cement; that is simply not true! Concrete cures as a chemical reaction between the Portland Cement and Water and hardens to full strength and hardness in about twenty-eight (28) days. As concrete is curing it is an excellent idea to keep it damp and even spray it with a mist of water to speed up the chemical curing process.
Also, concrete as it cures generates its own heat. That “natural-heat” along with the HOT water and calcium chloride is what allows concrete contractors to pour concrete in the winter. As the temperatures drop, just like the past several days, it is important to not have the water in the concrete freeze.
Many times, concrete is covered during the curing with huge “Thermal Blankets” that trap the heat from the hot water and the curing concrete’s natural heat. By trapping the heat, it allows the concrete to cure. And, the calcium chloride speeds up the curing process.
I am sure that all of us have seen lots of winter work with commercial projects where concrete foundations are poured. By taking relatively simple precautions, it is not very difficult to pour concrete in the dead of winter.
We wanted to talk about this because of yesterday’s series of inquiries and comments. Hopefully this helps.
Please let us know your thoughts. Call us at 802.985-5855