Hi I am using a digital moisture meter as a "pre-check" to the flooring contractors checks jsut to get an approximate moisture content of the concrete floor prior. I am getting .50% to 1.01 % values .5 reading low and 1.01 reading very high. 1% does not seem high what am I missing? By the way this is an Amprobe MT-10 moisture meter with a setting for concrete. Let me know what you know.
A digital moisture meter is ONLY appropriate to establish where to place your moisture tests. They only show you something as high or higher than the other thing. You use that to establish a good range of places to place tests per ASTM and then place your RH probes.
Yep, some guys down here do that before their RH testing ("some"= not many- I should, but don't see the economics in buying a MC meter just for that purpose).
I suppose it's a reasonable theory that if the MC is high (knowing that it's only the first 15mm of concrete or so, and knowing that some new concrete additives can skew the figures a little by interfering with the electrical resistance, etc..) then it's a good spot to place an RH sensor to get worst case scenario. But we are still none the wiser as to what relationship, if any, MC% has to RH%.
I see what you're asking- those numbers seem a bit low. Perhaps they're accurate and the MC is actually low. That's the issue. I recently did a test with a colleague where the specifiers requested a drilled resistance test as well as the RH test. Two resistance tests read around 5.0%, but the RH was 99% and 77% respectively.
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