What your contractor is calling "antifreeze" is actually an additive that accelerates the chemical hydration of concrete so adequate strength can be reached during the time that the heat of hydration, heated mix water and covering/insulation delay the freezing of the mix water.

To pour at 10 degrees an accelerator by itself is probably not enough.

The link below will explain the recommended precautions.

Here is a link that might be useful: Cold weather Concrete

Thanks - so it looks like its ok as long as they get the chemistry correct

Not just chemicals, but heated aggregate and water may be necessary, as well as adequate insulation afterwards.

My biggest concern though would be the footings. If they have been poured in above freezing weather, have they been protected for frost afterwards with straw, hay or blankets?

If they're being poured continuous with the walls, is the ground below free of frost? Has the ground been covered? Or excavated just before the pour?

Frost can penetrate five feet down in very cold regions. (You don't say where you're located.)

A careful gc and forming contractor will check all these things. Unfortunately, I've come across more than a few who answer every question with, "No problem. We do it this way all the time."

We are in Chicago , the footings were poured last week - it was also pretty cold then ( they look fine - but what do I know ) , the walls are going in this week

the footing is 10 feet down - the ground is not frozen ( at least not 10 feet down )

the footing is 10 feet down

Only when it's under a foundation that is backfilled on one side and open to a heated home on the other.

I build in Toronto where it has been down to -11 degrees C. on and off for a week. I would have used blankets. (But, then, I'm a notoriously nervous Nellie by-the-book type.)

Likely, you didn't get a hard freeze yet.

This post was edited by worthy on Mon, Dec 9, 13 at 15:45

We previously lived in the Chicago area. Our footers and basement were poured in February when the ground was definitely frozen. They were protected as described above. There never were any issues as long as we lived there. I'm guessing if there was an issue after we moved, one of our old neighbors would have mentioned it to us.

This might be too late, but if you are still concerned, look into a local concrete and soils engineering service. They should have a licensed engineer who can take a concrete sample when it is poured and test it. If the concrete is not developing per the specs, it may have to be redone. Does the concrete supplier have a warranty?
The concrete supplier should be using the right additives for the weather in your area, so usually this is not an issue. Every once and awhile there is a bad batch though.

I don't know on the warranty - but I will ask my GC . I think its going to be ok - they covered the whole thing with these blankets also. Apparently they do this all the time

but man is it cold out

is there any signs I can look for on the actual concrete for improper curing ? other than than the same ? I think its too late for that

"Our footers and basement were poured in February when the ground was definitely frozen."

OK as long a the footing was not poured on frozen ground.

Renovator8--The footers were well below the freezing line--at least 6 feet down if not more. It was 9 foot basement.

Depth below grade isn't a protection when pouring a footing. If the bottom of the excavation or the new footing is left exposed in below freezing weather the ground can freeze and disturb the footing when it thaws.