TM 5-852-4/AFM 88-19, Chap. 4
Table 2-3. Moisture Distribution in Cellular Glass after 20 Years Burial in the Annual Frost Zone, Fairbanks, Alaska"
Test
0 - 1"
1 - 2"
2 - 3"
3 - 4"
4 - 5"
5 - 6"
Area
%
%
%
%
%
%
RN-5
117.0
0.7
1.4
85.0
0.1
5.8
RN-6
115.5
2.1
2.1
103.2
104.3
1.8
76.5
4.4
5.3
26.0
0.3
0.6
RN-11
55.5
1.4
12.4
35.5
1.8
1.3
64.7
2.2
5.3
5.0
1.5
4.4
Notes on Tests Performed at 20 Years;
1.
Each test section was 50 ft square, asphalt-surfaced with the insulating layer in the middle of a 4 to 4.5-ft-thick
gravel layer on a silt subgrade. The insulation in RN-5 consisted of one 3-in. layer of 12-in. by 15-in. blocks, coated with
tar top and bottom, and with joints sealed by tar. The insulation in RN-6 and RN-11 was made up of two 3-in. layers. of
12-in. by 15-in. blocks, coated with tar between layers, and with Joints staggered and sealed by tar.
2.
Two samples of insulation from each test section were tested for moisture content as percent of dry weight. Data
are shown for each of the two samples.
3.
Before moisture measurement, sand and tar were trimmed from the samples. Samples were sliced into
approximately 1-in.-thick layers. 0-1 in. is the first 1-in. horizontal layer of cellular glass from the top; 1 to 2 in. the second
and so on.
4.
Large discrepancies are noted between values for the top inch of the bottom (3 - 4 in.) layer of cellular glass in
RN-6 and RN-11 and for the 4 to 5 in. layer in RN-6. This was possibly caused by water passing through the joints
between blocks and lying between layers where the tar bond is broken.
5.
It was noted that cell walls had deteriorated in the upper 1/4 in. to 1/2 in. of the blocks to the extent that the cell
walls could be easily broken by finger pressure.
2-40
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