Cold Weather Concrete - Curing Questions

DigitalFusion

I just poured a 32' x 45' slab 4" thick on Saturday afternoon up in mid-Minnesota. I havent ever done a cold weather pour before and want to make sure I do this right. The temps from Saturday morning to Sunday morning were 37 high, 25 low. Sunday to Monday the temps were 31 high, 25 low. We put concrete blankets on the slab as soon as practical, around 2 hours post pour, likely sooner. Its hard to tell as there was a flurry of activity during that time. At any rate we put them on immediately after power troweling.

The forecast for the week is as follows (as far as they can tell):

11-17: 29/18*
11-18: 33/27*
11-19: 37/27*
11-20: 32/20*
11-21: 30/24*
11-22: 33/28*
11-23: 35/25*
11-24: 36/24*
11-25: 30/25*
11-26: 32/26*

How long should I leave the blankets on there? The average temps for November as 41/25, but we have been below average all month. The average temps for December are 27/10. Should I leave them on there for the full 28 days? How long should I wait to drill the wall anchors in?

Thanks in advance!

house bldr

At those temps I would say about 1 week you should be o.k.

Chris Johnson

7 days and you will be fine, keep in mind even after 7 days there is a good chance you will still be able to scuff the floor

You can drill the wall anchors today if want. Are you epoxying bolts or using Titan HD's? If it's Titans, I would probably wait until you are almost ready to start framing.

If the sun is shining I would consider pulling the tarps and letting the radiant heat hit the slab surface if the temp is above freezing, cover it up an hour before sundown.

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Chris

concretemasonry

The ground in St. Paul is really not frozen now, so anything covered or protected just keeps getting better with time. This time of the year here, you will not get much sun except when it is clear, which brings the temperature down. Since you are local you sure realize. you never get real cold temperatures when it is cloudy. - If you are in central Minnesota, you wil be a few degrees colder.

It does not hurt to leave the blankets on when it is clear and cold unless they interfere with bolts or attachments.

Just make sure you get the blankets off before the next snow or you will have big problems.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

tkle

Seventy eight degrees out today. I wouldn't have a clue...