how cold is too cold for concrete?
hvtrimguy
| Posted in Construction Techniques on
I am trying to squezze in a 16′ by 18′ sunroom addition right now. we dug the frostwall perimeter friday. then we put hay in the trench and tarped it. (slab is on grade level scraped down just to remove sod.). now it’s been snowing all weekend (light flurries) and cold. tonight we are to get freezing rain. hope the tarp holds.
Anyway – any suggestions on keeping the concrete portion of this job moving foward without risk of heaving issues?
one thought I had was to tent the area. it’s not too big to do that.
thanks,
Jason
“it aint the work I mind,
It’s the feeling of falling further behind.”
Bozini Latini
Replies
I'm in Putnam County NY.
After this w/e I might be inclined to see if it warms up a bit. Check your trenches for frost/freezing.
If you pour, have your supplier add proper amount of anti/hydro and smother it all with salt hay and plastic tarps for a couple of days. Contain the heat generated by the cure.
[email protected]
What is salt hay?"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
After looking it up, I said, hmmmmm.
Not sure if what we used was the real thing or a generic term. I always assumed that the salt added to the heat or it's heat retention abilities or?
Saltmeadow Cordgrass - Wikipedia, the free encyclopedia
SALT HAY BALES[email protected]
Are yopu referring to the footings? I have hay in the trench and tarps over to try to keep the frost out. what is salt hay? or is that salt and hay? thanks for the feedback
"it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
Look at my post to fast Eddie. May be a regional thing. We would order salt hay to cover the ditches, the footing or a slab, then plastic and tarp.
It never fails if you are in a rush to pour. In a couple of days it will warm up.[email protected]
do you think I should get the footings going if there is no frost in the ground, then wait with it covered for things to warm up?"it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
If your excavations are not frozen and night time temps are only going into the upper twenties then I would go ahead. Leave the forms on. Cover everything with hay and plastic and tarps.
It looks like we are coming back to some warmer temperatures.
What are you doing a block wall?
Save the hay or straw and keep covering things back up at the end of the day. Get it backfilled as soon as you can.[email protected]
we are doing a block wall to match the existing foundation. Also , it's hard to reach the far wall with the cement truck so the block is easier than pumping such a small thing. today we shoveled off the snow, uncovered the tarps and pulled out the hay. the ground was dry and not frozen. we were able to get the footings in today.just out of curiosity, would ICF's be a good choice for winter pouring since they would theoretically protect the concrete some from freezing?where in putnam county are you? I used to live in dutchess and my father worked in montrose. I know the area a little.thanks,Jason"it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
hvrtrimguy
Most ICF manufacturers say you can pour into their forms with no risk of freezing ruining the mud down to a temperature of -20 C (-4 F), want to cover the top, of course.
Ron
just out of curiosity, would ICF's be a good choice for winter pouring since they would theoretically protect the concrete some from freezing?
I don't have a clue. Try doing a shout out to Gene Davis, he has a bit of knowledge with ICFs.
Glad you got your footings in. Keep them as warm as you can+lots of straw or hay or blankets..........
You can lay block if it gets into the forties during the day, even high thirties using the proper mix of anti-hydro in the mortar and covering your work at nite. I assume all you are doing is a pony wall or such? Should be able to knock that out fairly quick.
I'm in Brewster just off 22 north of the Red Rooster.[email protected]
One of the best reasons for using ICFs is for winter pours.You definitly need to keep the snow and ice out of them to begin with though. I knew a guy who formed 8' walls, then got careless about covering them. The night before he was going to pour, it snowed 18"
No way could he get enough heat inside them to thaw that out without melting the foam, so it was spring before he poured
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That time of year again already? <G>
If the ground is frozen you need to thaw it and recompact.
If the ground is not frozen, and the night temp stays above 28 degrees, it's not real risky. You want to batch the concrete with hot water or hot stone, an accelerant is helpful, less water is better, and cover it with concrete blankets. They are not that expensive. You can always sell them for 50 cents on a dollar the day after you don't need them anymore.
The first night is less critical because the heat of reaction is still happening. The second and third night are where the trouble usually happens. Keep it covered as long as possible.
If this slab is going to be exposed to the weather air-entrained is a good idea.
" You can always sell them for 50 cents on a dollar the day after you don't need them anymore."You have been around here long enough to know that is just plain WRONG.You sell them the day before you need them again..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill, that's the hardest I've laughed at anything here in a while.You are of course correct. <G>I can't stand the thought of how many times I've done that.The worst part is I'm thinking about selling an FL70 Freightliner and a 308CCR Cat excavator. This could REALLY hurt. <BG>
btw ....
for bedding fresh concrete ....
or lining the ground so U don't have to walk thru mud the whole time ...
U want "straw" ...
not "hay."
straw is bedding ... hay is food.
hay has sugar ... and breaks down almost immediately ... especially when laid around a construction site.
so ... ask for bales of straw.
not bad for a city kid ... I learnt this from my buddy Joe who had horses.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Not to mention that with hay the customer will have alfalfa growin in his yard next spring after the building is done!
So, how far can you push it? When -if ever- do you know you froze or harmed the concrete?
I have always treated concrete like water with ice being the bad guy. 25 degrees, no problem, just cover with visqueen for a few days. Was I wrong ? Lucky?
Always pour on non-frozen ground. Get real scared if below 25 degrees. Will provide heat after the first night for 2 days and nights. Royal pain and not cheap.
Never had a failure as far as I know. But I don't know what failed or frozen crete looks like or how it behaves.
I have poured down near zero. That get pretty scary and takes more extra work than it is worth in most cases, what with tenting and heat.Definitely never over frozen soilmixed with hot water and calcium, if there is no wind, I am comfortable down to 25-28 degrees with no cover. It makes its own heat.but for safety and because it is alwyas stronger when contained at higher heat, I always cover.with my slab last week, we did site prep and soil placement monday/tuesday covering each night with a taarp and curing blankets.Weather nasty wed and thursday - kept covered.Friday AM it was about 22°F when I got there at seven.Got it uncovered just as the sun was hitting it over the treetops.
Poured it and had a finish on by 3:30
We floated a plastic over it, then two plies of curing blankets, then the tarp.Next two days it was getting to about 15°FI am losing no sleep whatsoever.Last winter we did a lot of footings down to 15° with hay and curing blankets. No problems.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
You do things very similar to me. just wish I knew more about the stuff
What I basically see is everyone protect their mud for 2 days. 1st night the heat from hydration is great if above 25 days ( but we always cover, you never know it could be 10 degrees in the morning). 2nd night - blankets and tarps, no heat provided unless below 20 degrees predicted.
Do you know how long I need to protect mud from freezing?
Am I correct in assuming that all of the "free" heat from hydration is over in 24 hrs or so?
I get a feeling I have just been lucky to not have a ruined pour. But I ain't positive I know what frozen mud looks like. I kinda think it flakes or spalls on the surface, but not sure.
Am real scared of calicum. No experince with it and have heard many bad stories. Isn't calicum similar or the same as common salt? Can't be good for rebarr. I do really like it when they use aggretats from deep in the pile (warmer) and hot water.
after the ground is frozen 6-8'' deep it's time to give up for the winter.
"Do you know how long I need to protect mud from freezing?Am I correct in assuming that all of the "free" heat from hydration is over in 24 hrs or so?"I don't have the exact scientific answers, I'm afraid. Too much water in the mix is still there for quite a wile at low temp and with plastic over it, so it can freeze anytime. Too much crystalization ( water expands when it freezes) creates internal stresses that force the small aggregate apart while the bond is still weak.So the answer depends a lot on how cold is it and how much excess water is in the mix.The calcium chloride is standard procedure here. one percent in the mix. Yes, it can be hard on the steel, that's why never more than two percent is what I learnt.Protect for three days is standard MO here. Longer is always better, because the crete is still curing so the bonds are strengthening and becoming better able to resist the expansion of water as it crystalizes.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
http://www.cif.org/nom2005/nom-2005-26.pdf