Previous in Forum: apology didn't mean to offend   Next in Forum: chainsaw oiler question
Close
Close
Close
13 comments
Anonymous Poster

fresh concrete floor giving off gases

12/30/2009 5:15 PM

We poured a new concrete floor 1 month ago and have made ice on it since then but there are air pockets developing between the ice and the concrete. Does the fresh concrete give off gas for a period?

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
3
Commentator

Join Date: Aug 2008
Location: Kennedy Space Center
Posts: 87
Good Answers: 6
#1

Re: fresh concrete floor giving off gases

12/31/2009 1:25 PM

Concrete, new or aged is subject to vapor emissions forever unless you make the extra effort to seal the capillary or gel pore system found in all concretes. Sometimes referred to as " Outgassing ". Not only is a concrete expelling gases, but also moisture and chemicals within the matrix. Most common is Alkali found in all Portland Cement products. If you have heard the term " Alkali Burn " used in regard to a coating failure, this is nothing more than alkali coming to a surface, collecting at the coating interface causing disbondment, bubbles and peeling of the coating. You see terribly expensive epoxy applications to a concrete floor that will trap moisture under that coating and form bubbles where the moisture condenses. These type conditions are exacerbated when dealing with a low humidity air conditioned space, as the moisture in the concrete seeks the low R/H side of a concrete. StableCrete is a product used to penetrate the gel pore/capillary system, where it forms a solid inside the concrete to inhibit transfer of contaminates or moisture in or out of a concrete matrix.

__________________
Cost Effective Answer to Concrete Corrosion
Reply Good Answer (Score 3)
Power-User

Join Date: Aug 2009
Posts: 100
Good Answers: 8
#2

Re: fresh concrete floor giving off gases

12/31/2009 10:32 PM

The previous answer is quite correct. Without knowing exactly what was in the concrete you poured it is futile to speculate what is precisely occurring. If it is not out of the question to strip the ice, dry the floor and seal it I would heartily recommend it. Another very good product is Xypex. I would talk to your contractor and the ready-mix supplier before I decided on any course of action.

Good luck

Reply
Guru
Hobbies - DIY Welding - New Member Hobbies - Target Shooting - New Member Engineering Fields - Civil Engineering - New Member United States - Member - New Member

Join Date: May 2009
Location: Red Hook, New York (Mid-Hudson River Valley)
Posts: 4364
Good Answers: 177
#6
In reply to #2

Re: fresh concrete floor giving off gases

01/01/2010 11:23 AM

Hello Sourdough,

If my memory doesn't fail me, I believe that Xypex can only be applied either as an admixture (fresh concrete) or mopped onto the exposed surface of the new concrete during a short period of time (window of opportunity) after intial setup. I don't think you can apply it to a concrete surface that has cured for a period of time, unless that manufacturer has developed a newer product than I am aware of. Best to recheck their technical specs and application notes....

A very good product that I've used many a time in the past!

__________________
"Veni, Vidi, Vici"; hendiatris attributed to Gaius Julius Caesar, 47 B.C.
Reply
Power-User

Join Date: Aug 2009
Posts: 100
Good Answers: 8
#7
In reply to #6

Re: fresh concrete floor giving off gases

01/01/2010 3:56 PM

Greetings Captain.

I have actually seen some pretty amazing results from folks using Zypex on old basement walls that were weeping. I think it work fine in this application as long as there are no unusual reactions going on in the concrete. It would be interesting to know exactly what the mix was and under what conditions it was put down and cured in. It would also be good to know what the current conditions are. Is this in a bulk freezer or a skating rink or is it undergoing some sort of temperature swings? It would also be interesting to know what is underneath it.

So much to ponder

Reply
Anonymous Poster
#3

Re: fresh concrete floor giving off gases

01/01/2010 12:15 AM

They put exotic products in concrete now too. I often use broken concrete behind retaining walls as cheap backing. Rocks are sometimes expensive or hard to get. Sometimes the concrete chunks are a bit big and it would make your eyes water wheen you bust it smaller. Acrylic! Absolutely horrible smell.

Seriously, it was worse than painting.! And that concrete was several years old when they busted it up and still potent.

They put all sorts of fibers and accalerants and retardants in it nowaddays too.

I used to think it was environmentally friendly to use busted junk concrete in the backs of walls.

Depends on where it comes from, I guess.

Brian

Reply
Guru
United Kingdom - Member - Not a new member!

Join Date: Jun 2008
Location: USA/Europe
Posts: 4547
Good Answers: 68
#4

Re: fresh concrete floor giving off gases

01/01/2010 12:44 AM

Hi Guest,

As another post said without knowing the mix there is no way we can answer that. If you know the mix and it included ash.

You can read the site below and remember concrete is a natural product. The gas could be coming direct from the actual cement the concrete was made from or any of several additives.

What effect is this gas having on the floor or you?

The way round it is to seal it with a skim of polymer resin perhaps? Paint is not a good idea as it rarely seeps deep enough into the concrete.

Below is a site with advice on screeding. I have used a Latex screed with great success several times. It is pretty thin and it will find its own level. Just pour and spread with a 'float' or floor Trowel, running your trowel just slightly above any little peeks on the floor as it was finished. If the floor was troweled flat then just run the trowel over the flat surface as if you are spreading glue.

It needs to be only a ⅛" (3 mm), or less and it really easy to lay. But you must have the floor completely clear of everything including cars, shelving etc. Vacuum the floor before application of the latex to lift any bobbles of concrete that are larger that the depth of the Latex. I cannot recall how long it takes before you can walk on it but to be safe leave it a couple of days. You will then have a nice smooth finish which will stop any dust from the concrete floor and seal it. The instructions are on the tin, OK?

The first link is for Latex and other professional screeds

Latex+screeding+a+concrete+floor

screeding+a+concrete+floor

http://www.howtodothings.com/home-and-garden/a4631-how-to-apply-concrete-sealer-and-stain.html

http://en.wikipedia.org/wiki/Fly_ash

Happy new year and good luck!

__________________
Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]
Reply
Anonymous Poster
#5

Re: fresh concrete floor giving off gases

01/01/2010 10:46 AM

Id guess the Concrete is air-entrained.

Reply
Anonymous Poster
#8

Re: fresh concrete floor giving off gases

01/02/2010 1:35 PM

This is an ice rink. The problem is that we have an inch of ice on it and we are getting air pockets building at bottom between the ice and concrete. By the look of the replies, if we seal it in the spring, we should be good for next year. 4 feet of packed stone dust under the concrete, poured Oct 27th, temp was around 6 or 7 degrees C. Cured for 6 weeks before we made ice. Natural surface, no pipes, so no temp swings just frozen groound and then add water to make the ice.

Reply
Guru
United Kingdom - Member - Not a new member!

Join Date: Jun 2008
Location: USA/Europe
Posts: 4547
Good Answers: 68
#9
In reply to #8

Re: fresh concrete floor giving off gases

01/02/2010 4:03 PM

Hi Guest,

I appreciate you replying to the queries.

Is the air or gas pushing the ice up? It sounds to me as if there was some other agent in the rubble or the concrete or the ground under the two that may be producing this gas?

Is this a brand new site which has been reclaimed from a 'brown field site' previously? You can find out by asking the local Council.

If this is the case and the gas is escaping from the soil and not the rubble and or concrete you may need to get this checked out to see if there is any toxicity, and if there is anywhere else on the Rink, like the seating area, canteen etc, as well as around the edge of the ice that this gas is escaping.

On an old infill used for a rubbish tip and then left for maybe up to 20 years before the Rick was built, on such as a rubbish tip gas can continue to escape for many years. Usually a slab of concrete you would think would stop it but it does not. There is six sites near me where they were never able to build because there was too much continuous gas release. This is from the rotting process of food, card, paper etc, anything that can break down will and the gas, as I know as I see it most days is allowed to escape through many drainage pipes which only just break the surface grass. Even though it has been over thirty years since these tips closed the gas is still escaping.

I am not saying that is the case but, I have not heard of substantial gas leaking from and Rink that I know of.

The thing is, if you successfully seal the Rink will this gas cause a catastrophe in the seating area or some place else? It must get out some how.

Sorry for the pessimism. You will find out for sure only if a complete history of the site is known, and only if this history was kept up to date on a daily basis! It may take just a few loads tipped but not authorised to make the gas that you are having problems with at the moment.

I wish you well, truly I do but this will take some investigation by you and others before the truth come out?

Because the Rink itself does not take any of the structures weight, the concrete there where the ice is may be a lot thinner than the other structural areas of seating etc. The way round this you may find, might be to dig the actual Ice Rink up and go on digging until you hit solid ground? There can be no short cuts. All sites that I no of have not been built on in over 30 years, and there is a warning permanently on the site that gas is escaping. These sites have only soil and grass covering them, no buildings at all.

Sorry for the bad tidings!

Take care and sincere good luck.

__________________
Take it easy, bb. >"HEAR & you FORGET<>SEE & you REMEMBER<>DO & you UNDERSTAND"<=$=|O|=$=>"Common Sense is Genius dressed in its Working Clothes"<>[Ralph Waldo Emerson]
Reply
Commentator

Join Date: Aug 2008
Location: Kennedy Space Center
Posts: 87
Good Answers: 6
#10
In reply to #8

Re: fresh concrete floor giving off gases

01/05/2010 9:45 AM

Comments, suggestions and questions made thus far have merit! A review of engineering and contractor documents should provide answers concerning geo-tech possibilities and admixes or design criteria that might be affecting the slab!

"Air pockets building at the bottom between the ice and concrete" is an indicator of Vapor Emissions up through your slab, where the moisture becomes ice, leaving you with entrapped air underneath! [Air Pockets or Bubbles]. Suggestions of a crystalline waterproofing product as an answer probably won't work for you. A surface troweled/brushed crystalline product purports to work on the premise; when moisture is reintroduced to this type product the crystals swell, thus providing a waterproofing affect? This does not stop vapor!

I would recommend ASTM 2170 testing when the ice is removed to determine what the internal relative humidity of the concrete is and go from there. Will look forward to hearing how you solve this problem. Just remember, to think of your concrete as a big sponge absorbing and giving off gases until you seal it correctly!

__________________
Cost Effective Answer to Concrete Corrosion
Reply
Anonymous Poster
#11

Re: fresh concrete floor giving off gases

02/28/2010 5:56 AM

You said, "made" ice on the slab, so safe to infer an (indoor or outdoor) ice rink using piped refrigerant to remove heat and maintain freezing point. Have you considered a sand surface on the slab (piping imbedded)...which is (or long was) the standard method of artificial ice rink construction? Perhaps such would mitigate any undesired result of bubble formation?

Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 22699
Good Answers: 410
#12

Re: fresh concrete floor giving off gases

01/12/2022 6:29 PM

Yes it does de-gas, did was there a curing agent ardent like chlorine compound?… I believe the Hoover dam is still setting.

I just saw this thread is over 10 years old

__________________
“ When people get what they want, they are often surprised when they get what they deserve " - James Wood
Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 31078
Good Answers: 1728
#13
In reply to #12

Re: fresh concrete floor giving off gases

01/13/2022 6:39 PM

I would just have somebody go around and occasionally drill through the ice and vent the bubbles, then refill with water and Zamboni it...I might sample the gas bubbles to see what the gas composition was, and if was flammable, then I would burn it off...

__________________
Break a sweat everyday doing something you enjoy
Reply
Reply to Forum Thread 13 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

Anonymous Poster (4); babybear (2); CaptMoosie (1); Glenn Summers (2); phoenix911 (1); SolarEagle (1); Sourdough (2)

Previous in Forum: apology didn't mean to offend   Next in Forum: chainsaw oiler question
You might be interested in: Concrete Mixers, Precast Concrete Products, Floor Locks

Advertisement