How cold is too cold to pour the floor?

[Splinter]

Getting into that time of the year, lows in the 30s, highs in the 50s for the next couple of weeks, sure to drop a bit after.

How cold can you pour a floor? I know that the cure time will be longer, but I just want to make sure that I am still going to be able to do it.

pole barn, full doors and windows, insulated roof.

 

[dxdexter]

Ground temperature should never be below freezing or concrete can freeze on contact. The recommended minimum ground temperature should be 40 F (5C). Concrete will produce heat by the process of hydration, but this process is severely retarded at lower temperatures. The concrete will quickly lose heat and freeze at the surface if subjected to freezing air temperatures while still in its plastic state. You can protect the concrete from freezing with insulated tarps, straw covered with plastic or by heating.
DO NOT use heaters which exhaust directly into the heat source such as many salamanders. The concrete reacts with the carbon dioxide in the exhaust and will cause dusting of the slab surface by a process called carbonation. Most contractors in my area use indirect fired heaters (exhausted outdoors).

Most concrete plants in our area start heating the batch water after November 15. The concrete temperature should be a minimum of 10C (50F). and preferably should go no lower than this for 4 to 7 days, until the concrete can gain adequate strength.

There are a number of set accelerators and concrete anti freezes that can be used for cold weather concreting.

 

[comp]

interesting

 

[Splinter]

DO NOT use heaters which exhaust directly into the heat source such as many salamanders. The concrete reacts with the carbon dioxide in the exhaust and will cause dusting of the slab surface by a process called carbonation. Most contractors in my area use indirect fired heaters (exhausted outdoors).

I talked to a local guy earlier and he said throw a salamander in there and keep it above 40*, so that is interesting to know, thanks for the tip. I'll ask a couple of more guys locally too and feed back here.

 

[dxdexter]

I talked to a local guy earlier and he said throw a salamander in there and keep it above 40*, so that is interesting to know, thanks for the tip. I'll ask a couple of more guys locally too and feed back here.

Check this link out: http://www.construction-int.com/cat...rect-portable-heaters-prevent-carbonation.asp or research it on your own. We see the results of this every winter and they are not cheaply repaired.

 

[Splinter]

man dex, that doesn't sound like any fun...

 

[boiler7904]

Is the building up already and fully enclosed / insulated? If so, you could run heat for a while in advance to get the ground warm. After pouring the concrete, run an indirect heater through a window or door opening for a few hours a day (or evening) to keep the temperature constant.

 

[Splinter]

not totally. It won't be ready for concrete for a couple of weeks. I still have to get the electric and water run over to it...