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04.09
product manual
H-2755
Concrete Air Indicator
Directions for Use—(Ref. AASHTO T199-00, English Units)
Fill metal cup with cement mortar, excluding particles larger than
No. 10. Use a narrow blade to pick up mortar. Rod material in the cup
to compact mortar. Strike off excess even with the top of the cup. Clean
any mortar from cup and stopper.
Hold finger over stem opening and fill large end with isopropyl alcohol
to line on glass (alcohol may be inserted in the stem opening after
stopper is inserted, with syringe or dropper if desired).
Insert stopper in tube, invert indicator and adjust liquid level to top
line of stem making sure that all air bubbles are removed and that the
stopper is firmly inserted.
Place finger over stem opening to prevent loss of any liquid and
gently roll the indicator from vertical to horizontal several times while
tapping using a finger from the other hand until all the mortar has
been dissolved out of the cup into the alcohol.
With the indicator in a vertical position carefully remove finger from
the opening and count the number of spaces to the nearest 1/2
graduation from the top to the new liquid level. Use the number
indicated to compute the mortar-corrected air content as follows:
Example
For purpose of this example, we will use 6-1/2 as the number of
gradations from the top to the new liquid level. Assume for purposes
of this example, a mix with mortar content of 15ft3/yd3. Refer to
Table 1 on the other side of this document, which indicates for 15
the multiplier we would use is 1.22. Multiply 1.22 by 6.5 to obtain 7.9
percent mortar-corrected air content in a cubic yard of concrete for
this mix.
To compute the % air content in the mix, add the number obtained
for mortar-corrected air content to the curve correction factor found in
Table 2 on the other side of this document. In the case of our example
the result would be 7.9 + 1= 8.9.
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www.humboldtmfg.com
HUMBOLDT
Testing Equipment for
Construction Materials
Humboldt Mfg. Co.
875 Tollgate Road
Elgin, Illinois 60123 U.S.A.
U.S.A. Toll Free: 1.800.544.7220
Voice: 1.708.456.6300
Fax: 1.708.456.0137
Email: hmc@humboldtmfg.com
Table 1—Conversion Table for
Stem (Chace) Factor of 2.2
Table 2—% Air Content Curve
Correction Factor
Mortar Content Multiply Stem
Ft3/yd3 Reading By
10 0.81
11 0.90
12 0.98
13 1.06
14 1.14
15 1.22
16 1.30
17 1.39
18 1.47
19 1.55
20 1.63
21 1.71
22 1.79
23 1.87
24 1.95
25 2.03
26 2.12
27 2.20
Mortar Corrected Curve Correction
Air Content % %
1 -0.1
2 0
3 0.2
3.5 0.3
4 0.3
4.5 0.4
5 0.5
5.5 0.6
6 0.7
6.5 0.8
7 0.8
7.5 0.9
8 1.0
8.5 1.1
9 1.2
9.5 1.3
10 1.3
11 1.5
12 1.7
13 1.8
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