(1981) design method is selected for use by the U.S.
Army, estimates of stress through a variety of
aggregates, not just crushed rock, should also be
AASHTO-AGC-ARTBA Joint Committee: Sub-
completed so the design method can be adjusted
committee on New Highway Materials, Task
accordingly. More rounded material such as sand
Force 25 (1990) Guide specifications and test pro-
and gravel has been shown to concentrate stresses
cedures for geotextiles. American Association of
over a significantly smaller area on the subgrade
State Highway and Transportation Officials, Wash-
than crushed rock. Due to the likelihood that the-
ater of operations construction will be completed
Austin, D.N., and D.M. Coleman (1993) A field
with limited sources of high-quality aggregate, this
evaluation of geosynthetic-reinforced haul roads
would be an important addition to the current
over soft foundation soils. In Proceedings,
Geosynthetics 93, Industrial Fabrics Association In-
Finally, even though soils are usually only tem-
ternational, St. Paul, Minn., p. 6580.
porarily in a weakened state when they thaw, they
ASTM D 4595-86 (1998) Standard test method for
will sometimes have to carry more than 100 ve-
hicles during thawing. Thus, a method that ac-
strip method. 1998 Annual book of ASTM Stan-
counts for repeated traffic loading is desirable, and
dards, Vol. 4.09, Soil and Rock (II): D4943latest;
this should also be included in future development
Barenberg, E.J. , J. Hales, and J. Dowland (1975)
Evaluation of soilaggregate systems with MIRAFI
fabric. University of Illinois Report No. UILU-
ENG-75-2020, prepared for Celanese Fibers Mar-
SUMMARY AND CONCLUSIONS
Table 1 may be used with the design curves pre-
Bender, D.A., and E.J. Barenberg (1978) Design
sented in TM5-818-2 for convenience in using the
and behavior of soilfabricaggregate systems.
current Army geotextile reinforcement design
Transportation Research Record 671, p. 6475.
method. However, if 10- or 20-ton trucks are ex-
Fannin, R.J., and O. Sigurdsson (1996) Field ob-
pected to exert the maximum wheel loads on thaw-
servations on stabilization of unpaved roads with
ing or other low-bearing-capacity subgrade soils,
geosynthetics. American Society of Civil Engineers
Figure 16 or 17 (top) may be used, respectively.
Journal of Geotechnical Engineering, July, 122(7): 544
These methods both require the use of high qual-
ity aggregate. If the thawed layer is less than 0.4
FM5-430-001/AFJPAM 32-8013, Vol. 1 (1994) Plan-
m (16 in.) thick, these methods are likely to be con-
ning and design of roads, airfields, and heliports
servative. However, a geotextile separator will
in the theater of operations--Road design. Head-
probably still provide benefit to lengthen times be-
quarters, Department of the Army, Department of
tween maintenance of the gravel surface.
the Air Force, Washington, D.C.
If further research proves that the Giroud and
Foss, C.F. (1983) Jane's Military Vehicles and Ground
Noiray (1981) design method is adequate, consid-
Support Equipment. Fourth edition, Alexandria, Va.
erable aggregate savings for the U.S. Army would
Giroud, J.P. (1992) Biaxial tensile state of stress in
be realized by using it. However, since the Giroud
and Noiray (1981) design method may be
11, p. 319325.
unconservative, it should not be used by the U.S.
Giroud, J.P., and L. Noiray (1981) Geotexile-rein-
Army until further study is completed. A hybrid
forced unpaved road design. Proceedings, of the
method, combining a Boussinesq stress distribu-
American Society of Civil Engineers Journal of the
tion through the aggregate layer with a membrane
Geotechnical Engineering Division, September,
support mechanism as presented by Giroud and
Noiray (1981) might be an optimum design tech-
Kinney, T.C. (1982) Discussion of geotextile-rein-
nique. When this approach is further developed,
forced upaved road design. Journal of the
it should also include determination of represen-
Geotechnical Division, American Society of Civil En-
tative modulus values, the use of a variety of ag-
gineers, December, 108(GT12): 16571658.
gregates, the shape of the wheel load, and repeated
Herner, R.C. (1955) Effect of base course quality
on load transmission through flexible pavement.