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quikrete in cold weather...

Sco's picture

I'm building a 16' x 10' shed on concrete posts. I'm going to use quikrete poured into sono tubes for the posts each of which will extend at least 42 inches below grade and at most 4-5" above grade. I'm planning to pour them on friday but the forecast for friday and the following days calls for high temperature's of ~35 F with over night lows dropping into the lower 20's. Am i making a mistake pouring under these conditions and if so, is there an additive i can mix with the quikrete to alleviate any potential problems due to the cold???


(post #84643, reply #1 of 2)

what we do here(central alaska) when it starts getting cold, we'll pour a couple hours before the warmest part of the day then let it sit through the warm and cover it with plastic after a few maybe 4 hours... so long as the ground isn't frozen it should stay warm enough...

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(post #84643, reply #2 of 2)

Generally you want to protect it from freezing for two weeks, and not let it drop below 45-degrees fro at least three days.  If it is below 40-degrees it really isn't curing.

Things that might help:

Mix with hot water.  The hotter it starts out, (up to about 100-degrees), the better off you will be. 

Add some extra cement.  The heat of hydration, or heat the concrete self generates is dependant on the ratio of water to cement.  The less water, and more cement you have the more heat the mix will generate, which helps it stay hotter. 

Cover with plastic, and then straw or packing peanuts, and another layer of plastic. 

Calcium Chloride, or Potassium Chloride, both help keep the water from freezing and breaking the concrete apart while it is still green.  Both will also make it susceptible to break down, and possibly corrode any embedments.