DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Concrete, Stone & Masonry (http://www.diychatroom.com/f105/)
-   -   Poured concrete slab is not hardening (http://www.diychatroom.com/f105/poured-concrete-slab-not-hardening-181532/)

jruppert 06-08-2013 11:44 PM

Poured concrete slab is not hardening
 
2 Attachment(s)
First off, I should have come here before pouring my concrete but I didn't. So that being said, I removed a section of concrete wall in my basement to put in a patio door. Where the wall was removed it left a cavity between poured concrete floor and outside concrete walkway. I cleaned it out and used Quikrete, 3 60lb bags worth. Its been 5 days now and I noticed that it chips easy. This is the first poured concrete that Ive done and so I wasnt aware that I should have kept it wet. So is it too late to get it wet and lay plastic over it?

stadry 06-09-2013 06:28 AM

don't worry - we're used to folks finding us AFTER they mess'd things up :laughing:

from what you describe, sounds like too much wtr,,, we use several skids of that stuff a yr & never have trouble w/it,,, chip it out & dia ( do it again ),,, better luck this time

ps - would help if you'd put your location down when registering,,, not always the same advice for different parts of the country

jruppert 06-09-2013 09:37 AM

thanks for the advice. I was thinking that I will need to redo it. At least its not cured enough to be hard. If you dig at it at all it feels like strongly packed sand until it breaks apart. Then its just powdery. So you feel I used too much water?

As far as the location, I am seeing Michigan listed next to location under my user name in upper left corner of thread. Is it not shown for you? I live in Reed City, Michigan.

RWolff 06-09-2013 12:11 PM

Quote:

This is the first poured concrete that Ive done and so I wasnt aware that I should have kept it wet. So is it too late to get it wet and lay plastic over it?
It's too late if that much time has gone by, you may have added too much water initially, or because you didn't cover and keep it damp it dried out before it could cure, small patches like that can dry out real quick.

The patching concrete might work well ( doesn't look like a large area) and it doesnt need wetting down.
I did this threshhold repair at work on the garage door threshhold about 6 years ago, the old original concrete was elevated about 2" as a curb against water coming in, and it was all chipped and cracked. I applied the patching concrete and the aluminum threshhold with tapcons and it's held up well.

It doesn't see vehicle traffic since the floor slopes down steep to the basement, but it has seen plenty of steel and plywood slid or banged on it.
It was a vinyl concrete patching product but I don't remember the name of it, got it in a 10# bag at the local hardware store.

http://i.imgur.com/hDy33P7l.jpg

jruppert 06-09-2013 12:30 PM

2 Attachment(s)
I started chiseling away the loose concrete and after about an inch I got to some rather hard or harder concrete. It wasnt easy to chip away. Do you think I can get away with the patch stuff at this point and make it level? Do you think I need to put a certain amount in there and then use a self leveler to finish off? When I did my pour, I used 2 bags at the same time. I poured that in then realized I needed more. I stopped over at my dads and he had an extra bag. I took that bag and mixed it then finished it off. This was the part that was loose. So I must have had too much water in that part.

concretemasonry 06-09-2013 01:47 PM

jruppert -

The last bag you got from your dad may have been old or had been opened before and lost chemical reactivity.

Dick

oh'mike 06-09-2013 02:18 PM

Quote:

Originally Posted by concretemasonry (Post 1198081)
jruppert -

The last bag you got from your dad may have been old or had been opened before and lost chemical reactivity.

Dick

Yep---bad product---I can't save any powders at my house---I'm near the river and the humidity kills the powders in short order--so I always dump leftover powders and buy fresh for each job.

Mort 06-09-2013 03:43 PM

Boy, if it were me, I'd probably start all over again, but I've never used any of the patch stuff, so these guys that live on the other end of the chute would know better.

On the bright side, if you do redo the whole thing, you know exactly how many bags it takes.

jruppert 06-09-2013 05:08 PM

I took my bad concrete down to a section that was rock hard. I had to go roughly 2 inches and 3 at one end, which is exactly how my third bag was laid. I couldn't break loose the hard stuff. I went to lowes and bought a bag of quikrete patch. I put 3/4 of the bag into the cavity. We will see how this works.

stadry 06-09-2013 07:57 PM

dontcha just love these threads ? ? ? the longer we guess, advise, & wait, the more information we finally get :censored:

jruppert 06-09-2013 08:17 PM

So far my work is looking good or at least better than what I had before. :laughing:

I put some plastic over it and we shall see. The bag said to wait 1 day for foot traffic. Not sure if 1 day is sufficient for setting a door on it.

RWolff 06-09-2013 08:55 PM

Usually when the bags of Portland go bad from being stored and absorb humidity, you get lumps in it. If you can EASILY break up the lumps to powder with your bare fingers it can still be usable and will set, but once you get lumps that take effort to break up or cant be broken up with finger pressure, it's a gonner.
I've had a few bags at different times that were stored for a few months and they had lumps in them, I screened the lumps out (they were soft) and the concrete set fine, but then one time I ordered a pallet of 60# bags locally anticipating using it fairly quickly but didn't, and I wound up throwing out about 30 bags and they had been carefully stacked up in a dry indoor location, and it only took a few months or so and they had loads of hard lumps in them.

The hydrocal gypsum cement I use for casting seems to have a decent lifespan, I've had bags bought 3 and 4 years previously that were perfectly usable. Even with the bag open for months it doesn't tend to absorb moisture enough to ruin it and create lumps.

jruppert 06-09-2013 09:19 PM

Yeah this third bag that I got from my dad was laying on his basement floor. It did have some clumps in it that I had to break up. It wasnt too difficult to break up though. Maybe the bag had gone bad after all.

RWolff 06-09-2013 10:33 PM

Quote:

Originally Posted by jruppert (Post 1198279)
Yeah this third bag that I got from my dad was laying on his basement floor. It did have some clumps in it that I had to break up. It wasnt too difficult to break up though. Maybe the bag had gone bad after all.

If you were able to break up the lumps with light finger pressure to powder, it should have still be okay enough to set properly, but storing the bags on the bare concrete floor is a bad idea to begin with.
It's possible you got a bunch of lumps in the mix that didn't dissolve or break up, and you may have used too much water too, and it dried out too quickly.
I have noticed that Portland cement in this condition with soft lumps will usually take longer to set and cure, and doesn't get as warm, but in my case when I've used it, it always set.

Fresh stuff usually sets up quickly and in a thick pour it starts giving off heat from the chemical reaction pretty soon.

The stuff I used on the threshhold was not made by quickcrete, it was a vinyl concrete patching product that I bought it at Hardware Hank and it came in a bag not a pail. It was very smooth and nice to work with and can be used for filling thin/feathered patching. I believe that as long as your concrete is solid that it will go over, this should do fine for what you are doing there. As the photo shows it's held up well on the threshhold.

They only had 10# bags here, I couldn't say any other brand/type will work the same as what I used or not.


All times are GMT -5. The time now is 04:55 PM.