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**EXPERT Advice Needed** - VERY Moist Slab With LOTS of Vapor! What to do?

#31
JD,

Thank you for your kind words.

I have a call into our consultant re ASTM 309-07. As I pointed out to you silicates cannot be divorced from concrete, as concrete itself depends on silicate reactions CSH to produce the binder paste.

The issue is how they are employed and what is the end result. We all know Meta Silicates (unreacted silicate) create bonding difficulties for coatings. Why? because the upper densified layer, although harder and favoured as a warehouse floor hardener, does not control moisture transmission but can encourage it. But these have their use.

I am trying to get my mind arround your comments on VT as to why a technology that achieves in concrete, after the fact, what could and should be standard during batching is considered detremental by the adhesive manufactures. Seems they are allowing past poor silicate practice to dominate their thinking.

I have over the years tried (as flooring contractors who we solved their VT issue encouraged us to) to get this accross to their suppliers but I stopped trying. I have my clients who refuse concrete without the assistence of ICD hydration (we just had 3 days of suspended slab meetings and are now on the spec). Will not drop names.

Think of a floor concrete as a hard sponge, water or vapour can freely pass through its pore structure (thats what sponges are for) but why should this be so for concrete. Standard OPC concrete is pourous, even with low W/c and during the drying stage, the exiting excess mix water (which can be controlled by good hydration) is anything over 0.2 W/c. This will exit and carry with it not only residual Ca(HO)2 but if on grade (with or without a VB) other deleterious salts/contaminants. Yes there are all kinds or drying processes but the concrete can manage this itself if allowed.

None of our industrial slabs have VB's under them nor do we need drying assistence.

Now we havn't really changed the concrete, we have advanced the utilization of the two key ingredients, the cement and water so as to naturally enhance the hydration process. Yes we have used a silicate based solution ( Roman and modern engineers use pozzolans) to react with the cement. ICD takes the hydration reaction to a level that simply using powders cannot. I sent you SEM's of this fact.

Surface applied ICD silicate solutions are no different than the admixture ICD solutions except they have additional assistence for migration deep (not 1/8 to 1/4") into the substrate. Testing confirms that no residual meta silicates were evident after SEM evaluation. This promted the president of the testing lab to write " This is a fundamental advance in the science of concrete"

We have no harm testing and letters (unsolicited) from the Engineer who got his masters designing the concrete for the Kobe bridge in Japan and the ex QC engineer LaFarge now an independant where he summed up his dismay at how the industry has prefered inefficient admixtures over hydration technology.

Should not have said it was my last post.

Best regards.

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#32
John, I am glad you are back! I have much to learn, and you will be an excellent teacher.
I do not wish to come across as closed minded or a know-it-all. Concrete has been around for thousands of years and can be made using a number of ingredients and still we learn something new about it every day.

All I can go by, and this is it, the bottom line, is what the principal players in the game believe. If we have Ardex patch and Armstrong glue, the concrete must meet their ACI and ASTM parameters, and there can be no surface applied products for the purpose of moisture vapor suppression. If there is a failure of any kind I promise a concrete core will be pulled and analyzed and manufacturers will look for something they can use as a get-out-of-jail free card.

Where I do my work, a 20'x20' room may cost $250,000 to replace. When those kinds of risks are involved you can bet things have to be by the book (and there are a lot of books!). So as long as the players involved don't like surface applied silicates, hardeners and vapor reducers, then I can't promote them either, or I get left holding the bag....
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#33
As expected straight forward and to the point. Thank you. I believe I have to re-address how and what is needed to get to the heart of solving this excess MVT to comply with the "principal players".

And it is not technical because ICD does this right from the pour but it looks like it may be political. When we developed ICD there were no ASTM standards to comply with until C494 Type S came along. We were compared to water reducers, VMA's and SP's etc but non fit the ICD chemistry or functionality bill.

Got some research to to.

Best regards.

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#34
(11-04-2011, 05:51 AM)CC Solutions Wrote:  The density of the concrete doesn't concern me, as we have adhesives that can bond to non-porous substrates.

I cannot get an adhesive manufacturer to warrant their adhesive over a surface applied silicate product which is used for vapor reduction. There have been far too many costly failures with these products.

They have their place in the industry and work well on concrete that is not receiving floor covering.

Of course you're right- the same manufacturer('s rep) who first told me about their concern with "densifying/ curing compounds etc" also had a primer for non-porous surfaces. I don't think they actually knew it was the silicates causing the problems!

I look forward to seeing the unfolding outcomes of the ICD research to which John was referring...
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#35
I note no further input since last post. Unrelated to flooring but in reality it is, I have been assisting new clients with concrete domed roofs and precast walls below grade plus a new lightweight aggregate producer. What was in common with all these and flooring? How to stop water/moisture pass through the concrete right from the placement phase and if wanted to membrane application. Plus how to do this for consisently failing existing projects.

Domed roofs: Problem, shrinkage and permeability control. Solution: to know how to proportion and employ hydration enhancing (slicate) admixtures. After their first pour (gunnite application) dome was water tight and shrinkage controlled and placement time reduced.

Existing cracked dome: Problem, seepage through micro cracking (shrinkage). Solution: Rehydrate concrete matrix throughout by inducement of free water then application of silicate based (deep penitrant) solution, results cracking rehealed due to vigorous hydrate growth through 2" cover. After flooding no leakage and dome was bond ready (if wanted) for membrane.

Precast subgrade walls: Problem, dampness + dusting. Solution as above. Rehydration stimulation of CSH matrix production and in doing so consumed Ca(HO)2 to control and reduce dissolution of this hydrate and transportation through matrix. Dried below grade space.

Lightweight concrete (not shale): Problem, lack of strength and need to reduce VT. Solution introduction of cement enhancing admixture. Result, 30% increase in strength (applicable also to OPC standard concrete) with dramatic VT control and breathable membrane application achieved next day without delamination as mix water chemically locked. No delamination after coating after 3 months.

Only posted this to allow those who confuse meta silcate solutions to correctly blended and administered silicate technology that will produce no detrimental longterm charitaristics for concrete, verticle or horizontally placed or the [/size][/font]recurrence of moisture transference.

Best regards to all.
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