640-mm Tilcon common granular fill subbase
mean heave for the Raymark site during a single
layer for both the in-situ and saturated moisture
freezethaw cycle was approximately 68 mm.
conditions are presented in Appendices B and C
The predicted amount of heave could be classi-
in Internal Report 1179.* The upper layers of this
fied as high when the soil was modeled under
pavement structure included 100 mm of asphalt,
fully saturated conditions.
200 mm of graded aggregate base, and 640 mm of
Predictions of frost penetration into the soil
Tilcon common granular fill. The output from
during the freezing season reached 500 mm with
FROST provides daily cumulative minimum,
a moist soil, and 320 mm with a saturated soil
maximum, and mean estimates for frost heave, as
(Fig. 15). The frost depth penetrates to a maxi-
well as estimates for both the frost and thaw
mum depth of 200 mm into the Tilcon material
depth. Results for frost heave are shown in Figure
layer, less than halfway through the layer, and
14. When the water table was placed 2740 mm
does not extend down to the geosynthetic liner.
below the surface, simulating a pavement with a
low moisture content, the cumulative heave was
460-mm Tilcon material thickness
3.8 mm. This may be considered a low amount
At the request of NED, a computer simulation
of frost heave. When the water table was located
using 100 mm of asphalt concrete, 200 mm of
100 mm below the pavement surface, simulating
graded aggregate base and 460 mm of the Tilcon
a fully saturated soil, the maximum cumulative
common granular fill was run. This scenario was
70
Water Table Depth
60
Below Pavement Surface:
100 mm
50
2740 mm
40
30
20
10
0
1 Nov
1 Dec
31 Dec
30 Jan
1 Mar
31 Mar
Figure 14. FROST prediction of cumulative mean heave--640-mm subbase layer.
0
Asphalt Concrete
Graded
Aggregate
200
Base
400
Tilcon Common
600
Granular Fill
Material
Water Table Depth
Below Pavement Surface:
800
100 mm
Geosynthetic Liner Materials
2740 mm
1000
1 Dec
31 Dec
30 Jan
1 Mar
31 Mar
1 Nov
Figure 15. FROST prediction of frost penetration--640-mm subbase layer.
* Internal Report 1179 is available from the authors.
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