Mitigation eliminates the alkalinity.
It's the alkaline solution that attacks the glue.
No study required! Take a pH test when you remove a failed floor.
Cover a wet slab with plastic and take a pH test after several days.
And let's be clear that all slabs will have emissions... Low maybe, but the moisture is moving through them.
Sealing the slab is not the answer, either, Stephen.
However, allowing for a slowed-down transmission of vapor that doesn't react adversely with the adhesive or coating is the answer. Those suppression systems, either epoxy or urethane, are proven to work, depending on the RH level derived. We all know who manufacturers those. Added cost? Yes. Proven results? Yes. Within all applicable ASTMs currently on the books? Yes.
Frankly, I'm not sealing the slab.
My three questions to consider before drinking the kool-aid of sealers:
Have those sealers been officially tested with, and are they in compliance with, the manufacturer's adhesive warranties?
Do those sealers comply with the science we already have? (e.g. silicates are the best examples.)
Has Ardex, Mapei, or Koster weighed-in and accepted the sealer strategy yet? If not, why not?
There are a lot of companies rushing to market with the latest and greatest "fix" to seal the slab and eliminate the need for an RH test to be performed. They offer iron-clad warranties of total performance. Only the naive in this business will take the bait and switch without a full jury of investigative proof that they work. I'll call the CTL Group and/or the PCA before I ever subscribe to any of those tactics. Cut and run marketing has screwed this industry for years. I'm a bit more sophisticated than those approaches; I'm not signing on until I'm cleared by the scientists who I trust.
CTL does some great science. But, I cannot get any results from their testing on this matter of emission rates coinciding with rh levels in the slab.
Plus, if I were an attorney I'd have to say they have a vested interest in having the test results say what they want them to say. Doesn't CTL and Kanare have a vested interest in Wagner Rapid Rh?
That said I still believe it is the best rh device out there but the emissions part is not clearly answered.
As JD correctly stated, there is no correlation. Never has been. The reasons are many, but I'll state a few here:
1. Ambient temperature & humidity.
2. Water-Cement Ratio.
3. Use of lightweight aggregate.
4. The presence of curing compound.
5. How hard a floor is troweled.
6. How the test site is prepared.
The in-situ RH test method results are not contingent on any of the above criteria. On the other hand, the MVER test result using CaCL is totally and completely dependent on all of the items above because it is ONLY a surface test. This speaks to the utter unreliability of the CaCL test method because of the variability of those 6 items. Here are a few other major points that substantiate no correlation:
1. The CaCl₂ test determines only a portion of the free moisture near the surface of a slab, generally the upper ½” to ¾” only (12%-18% depth in a 4” pour slab). It is at best an estimate because it is based on no absolute parameters existing; changing aggregates, consistently changing ambient conditions, inconsistent w/c ratios, etc. Since nothing is standardized, how can a correlation exist between a lack of absolute variables in MVER and a totally controlled in-situ environment?
2. The CaCl₂ test provides no information about moisture conditions deeper in the slab where it has yet to migrate to the surface. There has never been one ounce of performance data that substantiates either a 3.0 lb or a 5.0 lb limit. The CaCL test also neglects the fundamental fact that adhesives play a major role in flooring performance.
3. Since there is no practical way to calibrate an MVER test kit, and since no standard reference concretes are available with controlled MVER levels, there can be absolutely no correlation.
4. The in-situ RH method is calibrated, equilibrated, and completely standardized. The very computation method by which MVER was established is still hotly debated; no historical data even exists for its initial implementation. This test was "winged" before winging it was ever in vogue. The Armstrong and Kentile Tech Wizards had the masses buffaloed until the Euros started asking the tough questions 56 years later.
By the way, the CaCL test has NEVER been used...NEVER...by any nation other than the United States. We were the only takers of the kool-aid since the day the clay putty ring and watch glass were first rammed down our throats in 1941.
I must have gotten you off track. I'm not arguing about wether or not which test to use but the surface structure of the power troweled surface's ability to breathe and have emissions or lack of. I been on plenty with no visable signs of any alkalinity issues, many of these even have a coating on top in commercial buildings/warehouses.
We understand that the surface conditions can affect moisture emissivity, but our point is readings emissions at one brief instant in time is really meaningless.
We need to know the potential the slab has, and RH tells us that quickly and easily.
I want to keep pointing out that Nora Rubber, the largest rubber flooring producer in the world doesn't care at all about MVER, but will not allow one square inch of flooring to go down without first conducting Rapid RH tests.
Just stop and think about what that means! What do they know, what testing on millions of square feet a year have they done, and what warranties are they carrying worldwide? That fact alone has to make you stop and consider why we should trust RH testing.
It is my goal to make you a believer Stephen.... I need to exorcise the Bob out of you.... MVER doesn't really matter anymore, not like RH does!