Table 8. Frost susceptibility test results.
1st Freeze cycle
2nd Freeze cycle
CBR test
Hv rate
Hv rate
CBR
Overall
Rating††
Material
(mm/day) Rating
(mm/day)
Rating
(%)
rating
Subgrade
1206
9.3
High
16
High
<1
V. high
V. high
1232
1
V. low
7.5
Medium
2
High
High
Class 3 special
stockpile*
10.5
High
14.5
High
5.5
Medium
High
Class 4 special
TAS†
10.7
High
12.4
High
3.5
High
High
Class 5 special
DGS†
3.7
Low
4.5
Medium
10
Low
Medium
Class 6 special
blended**
<1
Negl.
<1
Negl.
29
Negl.
Negl.
* "Stockpile" materials were furnished from stockpiles manufactured for Mn/ROAD
† Substitute material for modeling: TAS: taxiway A subbase; DGS: dense graded stone
** "Blended" materials were created by mixing separate size fractions
†† Frost susceptibility rating
8 hours of each cycle. The 8-hr heave rate is then
magnetic resonance (NMR) technique (Tice et
converted to an equivalent heave rate in millime-
al. 1982). The cooling curve data are presented
ters/day. The heave rate from the two cycles can
in Figure 13. The figure also include curves of
vary significantly, especially if the soil contains
calculated values used to represent the data in
large amounts of clay. At the completion of the
test, a CBR test is run on the thawed sample to
determine an index of the thaw weakening of the
soil. The sample's frost susceptibility classifica-
Table 9. Constants for unfrozen mois-
ture content equations (expressed as a
tion is then determined using the criteria shown in
percentage).
Chamberlain (1987). Results from these tests are
used as a relative index rather than a quantitative
α
β
Material
predictor of behavior.
Subgrade
Table 8 summarizes the frost susceptibility test
1206
11.085
0.274
results on the Mn/ROAD materials. The heave rate
1232
8.121
0.303
value listed for the base materials is an average
Class 3
determined from multiple samples. Of the two
stockpile*
1.497
0.709
clay subgrades, the 1206 sample had an overall
Class 4
frost susceptibility ranked as very high; the 1232
TAS †
3.0**
0.25**
subgrade ranked as high. The base materials had
Class 5
test results with a range in frost susceptibility.
DGS †
2.0**
0.4**
Class 6 special ranked as negligible and class 3
Class 6
special ranked as high in frost susceptibility. Dense
stockpile
+ No. 30
0.232
1.461
graded stone, used as a substitute for the class 5
No. 30
0.567
1.115
special ranked as medium, and Albany taxiway A
subbase, the substitute for the class 4 special,
* "Stockpile" materials were furnished from
ranked high in frost susceptibility.
stockpiles manufactured for Mn/ROAD
† Substitute material for modeling: TAS:
Unfrozen water content
Taxiway A subbase; DGS: Dense graded
The variation of unfrozen moisture content with
stone
**Estimated; no data available
temperature was determined using a pulsed nuclear
16
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