When to pour concrete

[sawtooth]

Well I'm a little concerned and need some advice. I have a farm in Ohio and am in process of building a barn on slab foundation. Problem is that it was supposed to be poured in October but never happened. Now its getting very cold and Ive been told cold weather is bad for pouring concrete. So should I proceed or wait till spring? My contractor doesn't seemed worried but I am.

Thank you

 

[RedNeckRacin]

We need some more info. Is the building heated at all? Is the slab insulated in anyway?

 

[LindenBruce]

Plus, they can add an additional curing agent so it cures faster as well. I think lime is one of them. B.

 

[BuilderML]

You do not want to pour on frozen ground period ! If it hasn't frozen yet your good. You will want to keep the pour covered until it has cured to prevent from freezing. This time of year you really need to watch the weather. If you see a few good days of fair weather ahead that would be the time to do it. I would not pour if the forecast is in the teen's and 20's.

 

[rsallen]

Calcium is what they add I believe.
There's no problem pouring in the winter or almost any condition for that matter, they adjust the calcium contents to the order.

If you trust your contractor to pour the poundage psi you require/want along with the finished product temps won't be a problem.

 

[paulharvey]

FDOT (Florida department of transportation) requires 40 degrees and rising at the time of pour. I would try to follow that.

Calcium: I know it was strictly forbidden in post -tension slabs because it could eat the cables up over time (or at least thats what I was told). I realize your probably not doing post tension, but does calcium eat rebar and WWF? I dont know, but might be worth asking.


Edit. I belive its calcium chloride they add

 

[kw22614]

I've been 'getting to' level, frame and pour a 40X12 patio slab out back for wifey all summer and fall and just haven't gotten to it yet. My neighbor, who has his own concrete business, says if I add 'antifreeze' to the mix, which is listed as 'other' cost from my supplier, I'd be good down to about 30*. Having worked in the construction industry for over 40yrs of my life, I think he's full of @*%#. Have seen the effects of too cold cure, too fast cure and ethelyne glycol being added under wrong (too cold) conditions that have caused extensive spalling, severe cracking, dips and not having the psi rating you pay for. IMHO I wouldn't pour or let concrete set to cure in temps any lower than about 38*-40*. This is for an outside pour with no insulation/gravel. Too many companies do cold weather pours solely for profits, as the rates they pay their help they can afford to keep sending someone back to do repairs. Don't do it Sawtooth - wait for spring!

 

[rsallen]

There are perfect scenarios but in the early 70's I remember working for companies ordering and pouring cement at anytime of year. Was it preferable to do it during warmer times? Yes. But it was done at all times of the year even if we had to shelter with plastic and run space heaters to keep the top water layer from freezing and it was done in commercial buildings with strict guide lines with sample tests.
One of the last ones I remember well was a 5000# floor in open air with only a roof and one wall, the temp was close to zero the morning of the pour.
I ruined a good pair of boots and gloves on that one but to this day it hasn't cracked or buckled and still maintains the pitch we finished it to.

 

[paulharvey]

There are perfect scenarios but in the early 70's I remember working for companies ordering and pouring cement at anytime of year. Was it preferable to do it during warmer times? Yes. But it was done at all times of the year even if we had to shelter with plastic and run space heaters to keep the top water layer from freezing and it was done in commercial buildings with strict guide lines with sample tests.
One of the last ones I remember well was a 5000# floor in open air with only a roof and one wall, the temp was close to zero the morning of the pour.
I ruined a good pair of boots and gloves on that one but to this day it hasn't cracked or buckled and still maintains the pitch we finished it to.

Although ive never worked north of Statesboro GA, I know and understand that on a major project, you cant simply wait six months to pour a slab, but they take extraordinary measures to do it. I dont know Ohio, but surely it gets into the 40s and 50s sometimes during the winter. Takes some planning, and a little luck, but I would try to pour at 40+, and if you use high early strength, even better.

 

[schmism]

my wife is a CE doing RE (resident engineer) work onsite at a new road building project. they follow IDOT regs which state they can not pour concrete unless the temp is 35 deg and riseing.

IDOT does not allow the use of additional curing agents for freezing weather. (at least when pouring 10" thick concrete that is going to be used for road)