UFC 3-260-02
30 June 2001
Nonfrost Design
Frost Design Thickness, mm (in.)
Thickness, mm (in.)
Traffic Area
Design Method
PCC
Combined Base
PCC
Combined Base
A
LSFP
406 (16.0)
432 (17.0)
318 (12.5)
432 (17.0)
B
LSFP
394 (15.5)
432 (17.0)
318 (12.5)
432 (17.0)
C
LSFP
305 (12.0)
457 (18.0)
254 (10.0)
457 (18.0)
D
RSS or
292 (11.5)
292 (11.5)
203 (8.0)
292 (11.5)
LSFP
241 (9.5)
508 (20.0)
(e) The combined base course can be divided into several layers having thicknesses
as given in the following table. With F3 soils, in lieu of drainage layer under the PCC pavement, a
drainage layer between the subbase and the separation layer should be considered. The divisions
shown are one of many possibilities. Judgment must be used when layer thicknesses are selected.
Separator
Drainage
S1 or S2
NFS Base
Combined Base
Layer
Layer
Subbase Layer
Layer
Thickness
mm (in.)
mm (in.)
mm (in.)
mm (in.)
mm (in.)
Traffic Area
A
432 (17.0)
229 (9.0)
--
102 (4)
102 (4)
B
432 (17.0)
229 (9.0)
--
102 (4)
102 (4)
C
457 (18.0)
254 (10.0)
--
102 (4)
102 (4)
D
292 (11.5)
89 (3.5)
--
102 (4)
102 (4)
(f) Compute the required depth of subgrade preparation.
Depth of Subgrade
Total Pavement
Preparation1
Thickness,
Frost Penetration,
mm (in.)
mm (in.)
Traffic Area
mm (in.)
A
965 (38.0)
1,067 (42.0)
-102 (-4.0)
B
940 (37.0)
1,067 (42.0)
-127 (-5.0)
C
762 (30.0)
1,118 (44.0)
-356 (-14.0)
D
584 (23.0)
1,118 (44.0)
-533 (-21.0)
1
No subgrade preparation required.
b. Example 2. Design an Air Force heavy-load pavement airfield. The design air freezing
index at the site is 26,660-degree Celsius hours (2,000-degree Fahrenheit days). The highest
20-21
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