Keep a slab wet if temps are around freezing?

[55stone]

Hey guys I had my slab poured yesterday morning. It was 72 yesterday and in the 50s-60s overnight. Now today has come and it's been hovering just above freezing and is suppose to be that way for a couple days. Down into the 20's tomorrow night.. I wasn't home when it got poured or before the guy pouring it left. He did send me pictures to keep me in the loop but he did not tell me to keep it wet for the next couple of days. I do not know what the concrete mixture was but with it being so cold should I not keep it wet or should i still keep it wet?

 

[ConCretin]

After 48 hours you are probably past the danger point where freezing temps will permanently damage the concrete. ACI 306 would tell you to cure the concrete at 55 degrees for 72 hours before exposing it so its probably a good idea to cover it. Concrete gains strength through a chemical process called hydration, which gives off heat so maintaining 55 shouldn't be too difficult.

Insulated concrete blankets would be ideal but anything that will retain heat would work. Even poly is better than nothing. If you are applying water, you can just stop and let the covering material retain the moisture. I'd keep the covering in place for seven days to ensure adequate curing.

Good luck and congrats on the new slab.

 

[dfiler2]

I would cover it, as mentioned, even a layer or two of poly would help. In my opinion, you would not want to spray it with water, that will just cool it down quicker, the concrete will be heating for a few days.

 

[Miss the Pontiacs]

My slab was poured just above the freezing point. It did dip below freezing in the evening. It was covered with insulated tarps and I do remember blowing off any water that accumulated on the tarps. Can’t remember if it actually rained or snowed. We started at 7:30 in the morning and the finisher was there till 9:30 pm. He was having a little trouble capping it due to the temperature. I set up lights for him to work with and moving them accordingly. In the end a great slab which I feel the conditions were partly the reason. Beats pouring in 70 degree or higher temperatures.