Cold Weather Concrete Pile Pour
 

I saw another thread on this site about pouring concrete in freezing weather and thought I would canvass subscribers on a concern I have. We are doing some reno's at the house that entail pouring 9 concrete piles about 4-5 feet deep. The guys were doing it today in -15 C weather which has me a little concerned, though admittedly I know very little about the subject. Will the concrete curing heat plus the ground heat/insulation be sufficinet to allow the concrete to cure properly? Or should we expect trouble? Would very much appreciate the more-knowledgeable feedback of others. Thx.

The Portland Cement Association (PCA) recommends that you maintain a minimum temperature of 55°F for concrete 12 inches and less in thickness, and 50°F for concrete 12-36 inches in thickness during the duration of curing (until the concrete has gained enough strength to withstand the cold temperatures). As you can see, the thicker the concrete, the lower the minimum temperature needed due to thicker concrete members retaining the heat of hydration better.

I would imagine your piles to be less than 12 inches thick. I'm not sure how much insulation the ground will provide for the heat of hydration alone, but I would imagine it probably isn't enough. In that case, I would recommend investing in a heating system of some sort to help maintain the minimum curing temperature (along with insulation). You may also consider moist curing methods to counteract the dry wintertime air.

Just my 2 cents.

You might consider using a Type III concrete, which sets faster so the heat of hydration is released quicker to keep the concrete warmer while it sets.

I don't know any specs or details but here in Winnipeg the winters get down to minus 30 c and we have construction all year round - house basements and commercial construction. All you need is heaters and hoarding. The ground down below 3 or 4 ft is never frozen anyways.

ACI 306R-10 Guide to Cold Weather Concreting

The objectives of cold weather concreting practices are to prevent damage to concrete due to freezing at early ages, ensure that the concrete develops the required strength for safe removal of forms, maintain curing conditions that foster normal strength development, limit rapid temperature changes, and provide protection consistent with the intended serviceability of the structure.

Concrete placed during cold weather will develop sufficient strength and durability to satisfy intended service requirements when it is properly produced, placed, and protected. This guide provides information for the contractor to select the best methods to satisfy the minimum cold weather concreting requirements.

This guide discusses: concrete temperature during mixing and placing, temperature loss during delivery, preparation for cold weather concreting, protection requirements for concrete that does not require construction supports, estimating strength development, methods of protection, curing requirements, and admixtures for accelerating setting and strength gain including antifreeze admixtures. The materials, processes, quality control measures, and inspections described in this document should be tested, monitored, or performed as applicable only by individuals holding the appropriate ACI Certifications or equivalent.

http://www.concrete.org/BookStoreNet...last-sep172013

I spoke with someone much more knowledgeable about construction than I am and learned that you can also use pre-cast concrete piles that have already been steam cured in a controlled environment. That's a much simpler solution than going through all the headaches of cold weather pours and curing.

ACI has updated the guide to ACI 306R-16.
https://www.concrete.org/store/produ...x?ItemID=30616