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Kapow! Low RH by Sundt

#1
Heck YEA!!!!!!!!!!

I have to find out from the GC how they did this. The GC is SUNDT. I don't know what magic they have but I want some. Amazing results. All these results are by an [ICRI] certified 3rd party tester.

All I can say is it has to be the rooms internal RH. Must have allowed the slab to dry. HVAC has only been on two weeks but building was closed up all winter.

Slab Grade On
Slab Construction Closed, drying from the top only
Slab Thickness (inches) 6 Inches

Data provided by contractor/owner
Slab Age Less than 1 year
Drill Depth (per ASTM standard) 2.4 Inches
Was HVAC Operational? End of April, 2013
Anticipated Floor Installation Date Mid-May, 2013

Interior Ambient Conditions
Ambient Temperature : 67 F
Interior RH (RH): 29 %
Tramex Concrete Encounter Meter: 4.5 - 5.25
Subfloor Surface Temperature : 71 F


Test No. / Probe No. / Probe RH % / Probe Temperature / Surface pH
1 / S431943 / 76% / 70F / 10
2 / S432311 / 75% / 71F / 10
3 / S432359 / 75% / 70F / 11
4 / S432020 / 75% / 71F / 10
5 / S432055 / 75% / 70F / 10
6 / S431980 / 76% / 70F / 10
7 / S431960 / 75% / 70F / 10
8 / S432420 / 77% / 70F / 10
9 / S432410 / 79% / 70F / 10
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#2
I'm assuming your incredulous that a Tramex concrete meter could achieve RH readings.
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#3
The tramex is used to find high low points pre test. Helps find issue spots to put probes into. Pretty stanard operating procedure for icri certified testing corps.
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#4
Opps they do require mc scans thus tramex. This is not even close the spreadsheet format they follow. I guess you are saying the tester did not do this thru IFTI.
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#5
Yep I miss typed. I have edited original post to point to ICRI.

I am talking about ICRI which is a real organization. ICRI is the International Concrete Repair Institute and they certify testing people to do testing. I try to always work with ICRI people. Some are good, some not. I called one in Nevada and he didn't even have a RH testing kit (let alone wagner). So you have to always check people out first.

Also, yea I just copy pasted the results. I'm not about to embed a spreadsheet into this forum. What a headache. But I've edited those results to try to be more clear.

...

...

Now lets get back to the point of the post. What great test results! I am still amazed. I have to figure out what they did. I wonder if they somehow used something like Airidus without telling me.
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#6
Maybe they used "spray and pray" and didn't tell you!

We all know that works... Confused
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#7
that is the point of doing the RH. Spray and Pray wouldn't give me a low result.
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#8
Here is what else I have learned:
1) Placement March 2012
2) Roof on for the Winter.
3) Wasn't rained on.

4) a/c has been on for over a month
5) heat was fired week of tests
6) crack repair done by Ardex Level Master Elite. After doing crack repair (some time ago) he hit the crack areas with a light grinding.

I got the mix submittal, any commentary would be appreciated:

Sand per ASTM C-33

Type II-V General Cement per ASTM C-150
- w/ BASF RHEOMIX 235 Admixture (specifically called out)

#57 1" Aggregate per ASTM C-33

Air Entrainer WR Grace Darvair 1000 per ASTM C-260

Type A Water Reducer WR Grace WRDA 64 per ASTM C-494

Potable Water

Air

4000 psi
3-5" slump
5% Min Air to 6% max (specifically called out)
Unit Weight: 146.4 #/cu.ft
W/C +P Ratio: 0.45
Designated volume: 27 cu.ft
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#9
Concrete slabs will dry at the rate of about 1" per month. So your 6" slab could dry in six months. We used to get those results consistently if we followed the guidelines.

Why is there air in the slab??? Is it outdoors? Subject to freezing?

I really like the LOW cement content of this slab.
When they spec less cement, they also use less water. Less water in = less water to dry out. Wink
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#10
Nope it is an indoor gym slab. Why would it have air is beyond my expertise (thus why I'm posting)

I'm not sure how you know what the cement % is. I have the Weight (lb) / Volume numbers for each part. Should I post that?

I also have a column called "specific gravity" but I don't think that is relevant.
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