Setting posts in concrete in cold (but not freezing) weather?

[In.the.Piñons]

I have a couple of very heavy signs (about 1200lbs) I want to set into the ground. Due to a bunch of delays, beyond my control, I'm wondering if I've missed the weather window for pouring concrete.

The highs are in the low 60's and the lows are in the low 40's for the foreseeable future. Is that going to be a deal breaking?

If it's important, the holes are about 2.5ft in diameter and 5ft deep. The posts themselves are 9x7", so lots of concrete is going into these holes.

 

[grsthegreat]

Your not even below zero. Should be no issues. Ground temps will probably be in high 60s

 

[BigGG]

∆∆∆∆
Yes, prime conditions. It'll cure a little slower but that's good. A heavy mass will generate heat while curing.

 

[In.the.Piñons]

Thanks guys. Looks like I'm good to go!

 

[fatjay]

The curing concrete will create it's own heat, you'll be ok.

 

[sandman2234]

after 4 hour preset, cover the concrete with an insulated tarp, or maybe a layer of foam board covered by a tarp. Keeping the heat in, that the concrete generates will help. We used a steam pipe to supply heat after the 4 hour preset because we poured the forms every other day and the concrete had to attain 3500 psi minimum before we cut it loose. The batch plant can make the mix hotter, but due to issues that can happen (like a traffic accident) speeding up the cure rate by making it hotter isn't always a good idea.
David from jax

 

[Rvrrat14]

Ground warmth, 35 and rising, no rain.

Good curing. Don’t water it down. If windy or cold, cover after pouring. Concrete gets its strength when cured evenly.

 

[CliffordK]

Around here the biggest issue is when everything turns to mush. But that hasn't come quite yet. It sounds like your temperatures are probably OK. Ground temperatures may be warmer than ambient temperatures, or at least slower to react.

 

[EddieWalker]

Temps are good. The biggest issue that I've seen with posts in the ground is not having the concrete come up above the surrounding ground so the water drains away from the posts.