# A question for the cold weather concrete guys



## Tscarborough (Feb 25, 2006)

The situation:

December 2007, fence posts were set into an SRW wall.
Recently we had a hard freeze (for us anyway) and some of the faces located at those fence posts popped off, exposing the concrete (It was bagged concrete mix). The concrete is soft and mushy, about like it had been poured an hour ago instead of 2 years ago.

The question:

What does concrete look like if it freezes before it sets?

Here is a pic of it in the wall.


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## Ayerzee (Jan 4, 2009)

Do you think that they just dumped the crete in and poured some water on top of it? (I don't know I'm just curious if doing that could cause that to happen)


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## Tscarborough (Feb 25, 2006)

No it is mixed well, has plenty cement in it, etc.


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## NJ Brickie (Jan 31, 2009)

I have never seen concrete get mushy from freezing before curing. I have seen it get flaky, soft, and brittle. When I say soft I mean if you hit it with a hammer it leaves a dent not being able to push your finger into like the picture.


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## 4th generation (Mar 28, 2008)

I've seen it turn back to sand & gravel not mushy & soft, however if it was encased and damp then possibly it could retain its shape & turn more clay like. Is there any signs of frost tracks ?


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## jomama (Oct 25, 2008)

NJ Brickie said:


> I have never seen concrete get mushy from freezing before curing. I have seen it get flaky, soft, and brittle. When I say soft I mean if you hit it with a hammer it leaves a dent not being able to push your finger into like the picture.


 
Same here, flaky & somewhat soft yes, but I've never seen concrete mushy like that.

That seems to be a fairly big cavity for a SRW as well. Must be a pretty deep or hollow unit?


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## CanCritter (Feb 9, 2010)

mushy sounds like its just starting to thaw...that pic dosnt look good atall


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## tgeb (Feb 9, 2006)

I have never seen anything like that.......ever.


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## neolitic (Apr 20, 2006)

Looks like one for the guys
at Texas Tech or Perdue. :blink:
I've never seen concrete remain
plastic for two years.
Can't imagine how to create
the conditions for that.


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## CanCritter (Feb 9, 2010)

k ..missed the 2 year part....wondering if they just put post in and packed a dry pack around it and left it...

now for the bad news.....l reread...they put wooden posts in blocks then filled with whatever...theres a good chance that " every" block with a post in it will crack or pop givein time...what will happen is post will eventually get wet and swell...this force will pop the block....gotta remember this is how many cultures split stone was with wooden wedges in cracks then wetting them...

below is a pic of a post a HO wanted fixed and is basicly the same principle...no room for wood to expand,,,generaly a cause of bad flashing sealing ect...post gets wet expands and splits whatevers holding it ...post gets wet...frezzes and when water freezes it expands...as much as l hate to say it this fence was doomed from the get go

on the post below you will also notice the red tints...this is from someone takeing a tiger torch to the stone in a effort to dry or thaw the stone...cultured stone will generaly burn like this if a torch is left on the stone face to long...also the motar was to stong which made it split right through the stone...correct motar mix wouldve had this post split at stone joints thus being easly repaired with some pointing..now the whole post had to come down...chances are this woulda been as far as it wouldve swelled... in all a bad job


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## Tscarborough (Feb 25, 2006)

They are metal posts, not wood, and for us to get 2 days in a row below 32 degrees is rare. The hard freeze was a couple of weeks ago. Samples sent to the lab. Definitely like nothing I have seen before.


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## Girlscanbld2 (Feb 12, 2010)

I know this sounds crazy, (and I'm probably gonna take a hit on this one), but I sometimes use bag concrete to do sculptures. Years ago I was working in a spot where the hose didn't reach so I carried water in a 5gal bucket. Weeks later the project was still soft....after days of trying to figure this out I realized that I used the bucket that I stored Copper Sulfate (for the pond). I have since done experiments and found that the dirty bucket was the culprit. Maybe they used contaminated water for mixing?


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## neolitic (Apr 20, 2006)

Girlscanbld2 said:


> I know this sounds crazy, (and I'm probably gonna take a hit on this one), but I sometimes use bag concrete to do sculptures. Years ago I was working in a spot where the hose didn't reach so I carried water in a 5gal bucket. Weeks later the project was still soft....after days of trying to figure this out I realized that I used the bucket that I stored Copper Sulfate (for the pond). I have since done experiments and found that the dirty bucket was the culprit. Maybe they used contaminated water for mixing?


By George, I think she's onto something.
I was thinking contamination,
but couldn't think of what.


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## dakzaag (Jan 6, 2009)

Girlscanbld2 said:


> I know this sounds crazy, (and I'm probably gonna take a hit on this one), but I sometimes use bag concrete to do sculptures. Years ago I was working in a spot where the hose didn't reach so I carried water in a 5gal bucket. Weeks later the project was still soft....after days of trying to figure this out I realized that I used the bucket that I stored Copper Sulfate (for the pond). I have since done experiments and found that the dirty bucket was the culprit. Maybe they used contaminated water for mixing?


 
I think you got it right on. Only way for portland and water not to get hard is when you block the reaction. Some substance from somewhere was introduced most likely to the water and prevented the reaction from taking place. I give this one to the lady in the second row.:thumbsup:


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## Diamond D. (Nov 12, 2009)

this happened to me on a hammack post , years ago. i mixed the sacrete in a 'barrow with clean potable H2O, so if there was contamination it was in the bag. after the post leaned to the limit i dug it up , only to find the concrete was like clay. i just asumed the bags that were in the garage for so long,( i wouldn't use it for a customer ), that the cement got to old and hard and there was no chemical reaction. that was my opinion.


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## Rockmonster (Nov 15, 2007)

Metal, maybe galvanized? Zinc is known as a hydration retarder....I would assume it would have to be a lot of zinc....I'm going to look into this further....I don't know anything about copper sulfate, but I'm going to look into this as well....


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## CanCritter (Feb 9, 2010)

this is gittin interesting......


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## concretemasonry (Dec 1, 2006)

Fertilized can also do a job on wet or curing concrete.

The retaining wall units seem to be fine, but they were cured before construction. Was there grass or sod on the fill behind the wall? If so, and the fertilized ran down to the post, the fertilizer could get into the concrete before. If the concrete mix was poured dry and some water was added the curing is still slow and unpredictable and the concrete is very susceptible to chemical attack that can kill the curing.


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## dakzaag (Jan 6, 2009)

Dick,
I suspect something similar, but it seems to me it would have to be mixed into the concrete a little more completely to get a mush ball like he has. Small holes like that almost always indicate complete cement in bags that are mixed on the job, or sometimes just poured in dry and allowed to set up from atmosphere moisture. 

In Indiana, we can pour dry mix into a hole like that and come back in a week or two and it is hard as normal concrete. Our humidity is usually high and we get regular rains that would contribute to the curing process. We can't leave a bag sit on a cement pad for a week or it will start setting up (even stored inside) and get clumps. 

I am constantly running into this with sackrete bags and specmix mortar in 60 or 80# bags. I know the suppliers who manage their dry mixes and those who sell clumpy stuff. After two years in my climate that would be hard as any concrete from the plant. (It might not test 4,000 psi, but it will be hard and strong enough to do that job.) 

Since the OP is in Texas, his environment may slow the process, but surely by now it would have set up. Since it is mushy, something interfered with the reaction. I wonder if a soft drink was poured in with the mixture. The landscape guys will spray pepsi on a curb while it is wet and later wash the curb with a hose and take off the "cream." That's how they get exposed aggregate or at least how some of them do.


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