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CaCl and RH correlation?

#7
These are two different tests completely. I do both and then explain what the results mean to the principals.

Be cautious when grinding floors to conduct CaCl tests!!!! This is not in the ASTM, and for good reason.

If you come upon a floor that has a mitigation barrier installed, you may very well remove it with a grinder and get erroneous readings.

You may remove a natural moisture retarder, the steel trowelled surface of the slab.

If you remove a lot of concrete, say 1/4" or more, you will get a much different reading.

My preparation is as the ASTM states, remove foreign substances to a clean slab. I also often prepare the slab as the flooring contractor will prepare the floor. If he will sand the concrete, so will I.

This is where the RH test will help you determine the potential of moisture in the floor. If you have a hard trowelled floor and get very low MVER, but your RH readings are quite high, advise the principals that the moisture will work through the hard concrete surface over time, and there is plenty of drive to make sure it does.

Conversely, you may get a high MVER and have low RH values. Perhaps the floor was flooded a few days before you placed the CaCl test, and you are reading the wet top layer. In this case you could tell the principals that the slab is actually dry but the surface should dry off for a few days with fans or dehumidifiers.

These two tests are both important!
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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Messages In This Thread
CaCl and RH correlation? - Bryan F - 09-12-2008, 05:40 PM
RE: CaCl and RH correlation? - rthompson - 09-15-2008, 04:24 PM
RE: CaCl and RH correlation? - Bryan F - 09-26-2008, 09:48 AM
RE: CaCl and RH correlation? - CMoore - 10-02-2008, 01:43 PM
RE: CaCl and RH correlation? - rthompson - 10-21-2008, 11:56 AM
RE: CaCl and RH correlation? - CC Solutions - 12-17-2009, 12:34 PM
RE: CaCl and RH correlation? - Ernesto - 01-12-2010, 09:54 AM
RE: CaCl and RH correlation? - Ernesto - 01-13-2010, 03:26 PM
RE: CaCl and RH correlation? - Ernesto - 01-16-2010, 09:16 AM
RE: CaCl and RH correlation? - Ernesto - 01-26-2010, 11:49 AM
RE: CaCl and RH correlation? - Ernesto - 01-27-2010, 12:56 PM
RE: CaCl and RH correlation? - eaadams - 07-09-2010, 11:56 AM
RE: CaCl and RH correlation? - mwoody - 08-31-2010, 10:34 AM
RE: CaCl and RH correlation? - eaadams - 08-31-2010, 10:47 AM

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