Pouring concrete in winter. Question..,

[sawtooth]

Ok so our new home is almost finished so its about time to pour the driveway. This in VA so seeing some freezing temps. The contractor says no worries as they use additives to keep things from freezing. So my question is does these additives hurt, make weak, or damage the concrete long term? Should i be worried about this?

Thanks

 

[murphy1244]

I have never seen a Cement Truck out in the cold.

 

[Bigkrank]

They just poured 740 yards in an addition at work last week. I would never pour concrete on frozen ground though.

 

[adirondackmtnman]

Ok so our new home is almost finished so its about time to pour the driveway. This in VA so seeing some freezing temps. The contractor says no worries as they use additives to keep things from freezing. So my question is does these additives hurt, make weak, or damage the concrete long term? Should i be worried about this?

Thanks

I'm guessing that they're speaking of a set accellerator, and if dosed corretly, they should have no impact on the finished product. Do you have frost in the ground? If not, have them throw some blankets over it to keep it from freezing. Anything too cold, I personally would want to hold off until spring.

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[sawtooth]

I'm guessing that they're speaking of a set accellerator, and if dosed corretly, they should have no impact on the finished product. Do you have frost in the ground? If not, have them throw some blankets over it to keep it from freezing. Anything too cold, I personally would want to hold off until spring.

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The top of the ground is frozen right now due to the cold snap that came through. However, we will have highs in lower 60's by weekend so it will thaw out. I know he plans to do it on a warmer day but it till may be around freezing at night. Just worried these so called additives may become a issue down the road as the builder will be long gone by then.

 

[CurlyDave]

I would wait for warmer weather.

There is a divergence of interests here. You want the best outcome possible. The contractor wants to be paid as soon as possible. Never forget this difference.

I have no doubt that he can get an acceptable result in cold weather, although from what you said at first about "additives" he might not be as experienced as you think. He should have been able to name the additive used (out here it is calcium chloride), and specifically what it does.

I am also certain that the result will be better if you place the concrete when it is warmer.

For a general contractor building a spec house, it really doesn't matter when they pour, the result will last long enough to sell the house. OTOH, you really care how good it looks 10 years out.

 

[mark54]

I would not recommend it. Here in the Chicagoland area the readymix suppliers cutoff date for backing up the performance on their product is November 1st as they cannot predict 30 consecutive days of above freezing weather. Wait until spring when the ground thaws and the temps are 40F and rising and you will be fine. I did this work for 30 years and know what I'm talking about. Mark54

 

[adirondackmtnman]

The top of the ground is frozen right now due to the cold snap that came through. However, we will have highs in lower 60's by weekend so it will thaw out. I know he plans to do it on a warmer day but it till may be around freezing at night. Just worried these so called additives may become a issue down the road as the builder will be long gone by then.

The additives are ok, like I said, as long as they're dosed correctly. The admixture and dosage rate should be printed on the batch ticket, and it wouldn't hurt to call the ready mix plant and ask them what they will use. I would prefer a non-chloride accellerator, as it will protect the rebar/mesh from the corrosion a chloride based accellerator will cause. If the ambient temperature during the night hovers around freezing at night, you'd probably be ok due to the heat of hydration. If its a concern, blankets will do a good job. If the contractor is any good, he'll know that. I'd be more concerned with proper subbase prep than the cold right now.

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[adirondackmtnman]

P.S. if you wait, be sure he doesn't come back when it's scalding hot outside, the heat is just as bad as the cold

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[Zick]

I would wait for warmer weather.

There is a divergence of interests here. You want the best outcome possible. The contractor wants to be paid as soon as possible. Never forget this difference.

I have no doubt that he can get an acceptable result in cold weather, although from what you said at first about "additives" he might not be as experienced as you think. He should have been able to name the additive used (out here it is calcium chloride), and specifically what it does.

I am also certain that the result will be better if you place the concrete when it is warmer.

For a general contractor building a spec house, it really doesn't matter when they pour, the result will last long enough to sell the house. OTOH, you really care how good it looks 10 years out.

Excellent advice! :thumbsup: