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Calcium Carbide testing and Silicates

#11
Bill,
Let's think about this for a moment and see if we can figure the answer out ourselves.

Do the test parameters limit the concrete sample to the top treated horizon of the concrete only? I am assuming it does. The top would be the driest concrete horizon.

The next thing to consider is the test results we expect to see. Carbide testing is going to tell us the percentage of water in a sample. Flooring manufacturers want to know one of two things: The moisture vapor emission rate (MVER) or the concrete's relative humidity (RH). These tests are governed by the ASTM's associated with them for use by the flooring industry and have exact protocols that must be followed for the test to reveal usable results.

ASTM F-2170 for in-situ RH testing dictates reading the concrete slab at the 40% depth horizon for a reason. It has been determined through scientific testing that the 40% depth horizon accurately represents the moisture content of the slab while it is drying and at equilibrium. If the carbide test is only reading the top horizon of the concrete what good will that be? Likewise if we carbide tested the bottom of the slab what would that show us? The top would be drier than the bottom, but what does that mean? We have no manufacturers that recognize carbide testing at any horizon and specify a moisture acceptance level.

It could be a valid test if properly performed, which I would suspect would mean coring an entire profile piece from the concrete, full depth, and determining the moisture content of that piece. That will quantify the moisture content of that piece of concrete. But we still don't have a flooring manufacturer that recognizes the test and specifies a moisture content level.

So to answer your question, remind you I am not familiar with the test, yes you can test the free moisture content in a sample of concrete treated with a silicate. But what will it tell you?

I'd start with the question first, asking what you are supposed to find with this test, then we can determine if the test is appropriate.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#12
Question 
How did the concrete become contaminated by silicates?
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#13
(09-18-2012, 12:40 PM)Concrete1421 Wrote:  How did the concrete become contaminated by silicates?

Exactly!! Big Grin

Who would ever put silicates on a slab destined for flooring???? Huh
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#14
The only other thing we know is that Calcium Carbide testing is mainly used to test the moisture content of screeds. Far as I can tell screeds are about the only place you'll find a manufacturer warrantying on a CC test. I had a link but am too lazy to find it right now.Tongue

Whereas...not many flooring/adhesive/VB manufacturers warranty over concrete treated with silicates...
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#15
Talk about a manufacturers smoke screen.
The silicate manufacturer is attempting to use this european testing practice since the flooring material was manufactured in Europe and they publish 2% as acceptable.
This job is only 1500 sf and the silicate manufacture wont step up to the plate. This should be fair warning for any clients that are contemplating using this questionable technology.

The flooring material was installed over crumb rubber using a 1/16 x 1/16 x1/16 sq. notch. The flooring material has swelled (due to moisture) and adhesive application was not uniform which caused the bubbles to occur where not enough adhesive was applied. Some areas were bonded with tenacity while other experienced bubbling. I tried to explain to the client that it was a combination of things (moisture and inconsistent adhesive application) that caused this failure, but seeing that the GC hired the flooring contractor whom he has had a long relationship with and that he recommended the silicate) he is defending the flooring contractor and the use of the silicate."why am i not surprised"

As far as the testing goes, had to tell them a few times that we were in the USA and 2170 and 1869 applied but they don't want to hear it.

The question remains... Does the application of applying a topical silicate void the Calcium Carbide test? Does it alter the test results?
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#16
Sorry to keep bouncing away from your question Bill, but have you seen the test standard used in Europe? I haven't. I'm wondering if they test the top half of the slab or the top 1/4 or what. If you find discrepancies between test methods, it's a great place to start.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#17
It was applied to stop MVER

It was applied to stop MVER. You can google this info and see a demonstration on U tube.As far as who's doing it. Everyone that would believes some sales person who doesn't know or care what he does to his client ,only cares he makes a sale.
I should be grateful as people like this keep me in business.
Bill
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#18
I know exactly what you mean.... I'm in a pretty lengthy 'discussion' about this on LinkedIn with a silicate pusher.... Dodgy
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#19
(09-19-2012, 06:40 AM)Lepito Wrote:  The flooring material was installed over crumb rubber using a 1/16 x 1/16 x1/16 sq. notch. The flooring material has swelled (due to moisture) and adhesive application was not uniform which caused the bubbles to occur where not enough adhesive was applied. Some areas were bonded with tenacity while other experienced bubbling. I tried to explain to the client that it was a combination of things (moisture and inconsistent adhesive application) that caused this failure, but seeing that the GC hired the flooring contractor whom he has had a long relationship with and that he recommended the silicate) he is defending the flooring contractor and the use of the silicate."why am i not surprised"

Someone installed Lino on top of recycled crumb rubber? This is starting to take shape in my mind. 1/16" sounds familiar. The rubber was probably 4' wide goods. So, was the rubber was installed with say a one part moisture cured urethane or was that also with G21?

There is a reason DLW for sports requires metal/steel plates above the rubber layer in Europe... Let you jump to your own conclusions on that one.

We did some of the first sales of this sort of thing in California some time ago but with a vinyl on top not lino. We would get problems like you describe but it was because of an imperfect bond between the flooring and rubber. Those rubber products are inherently inconsistent. I have an e-mail here from the old technical manager at the PA based company their tolerances which just blew my mind as they basically say those products are recycled and thus can be inconsistent. Anyway, it was quickly discovered that you must use at minimum a double layer cross layed and glued down fiberglass screed to prevent the two materials from having the issue you describe. (usually under load areas) Those areas were not consistent. The same load at two places would cause different results. The same manufacturer with very close ties to Mapei & Armstrong are doing some interesting things in 'field tests' in the north east, I'd make sure this isn't one of those jobs.

Also, sometimes with that rubber it isn't so much a mater of enough adhesive but the rubber is variably porous. That is why the poured in place gym floor people have to seal/prime the floor before they install the urethane top coat otherwise the sub-floor can just suck up anything on top.

My heart does go out to the installer. G21 is a bear to work with. Few installers can get it right as you must have 100% focus and patience to not try to lay too much too fast. I can't imagine using it in this manner.
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#20
Hello Mr. Lepito, I am the first inspector/testing agent on that job. I am surprised to find that has not been taken care of by now. Researching the carbide testing turned up nothing on my end either other than it's use in Europe. My next step was to locate the ASTM for it but found only one for soil using the carbide testing. My question was the same as to contamination as 1870 says concrete must be cleaned with no contaminants. The other side of the whole problem is the company, to my knowledge, has not said why the Lino blew off. Ambient does not cut it. My apologies for the syntax, or lack of, this is off my iPhone.
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