TM 5-830-3/AFM 88-17, Chap. 3
b. Silts or clays (low liquid limit). The moderately
overruns, and parking areas of airfields.
-Runways, taxiways, taxi-hover lanes, and landing
permeable, low to medium plasticity, fine-grained soils
and parking pads of heliports.
encompass USCS types ML, CL ML-CL, and OL.
c. Sands or gravels (with fines). The moderately
-Tank trails.
Economic analysis of the cost to maintain an unsurfaced
permeable, coarse-grained soils contain an appreciable
road versus the costs associated with a paved surface
amount of fines encompassing USCS types SM, SC,
road indicates the break-even point occurs at a traffic
SM-SC, GM, GC, GM-GC, and GW-GM. CL Sands (with
level of approximately 100 vehicles per day. A durable
little or no fines). The highly permeable sands or gravelly
riding surface such as an asphalt mixture or portland
sands contain little or no fines encompassing USCS
cement concrete should be considered when unpaved
types SW-SM, SP, and SW.
roads are trafficked by 100 or more vehicles per day.
e. Gravels (with little or no fines). The highly
Where these areas are considered permanent, they
permeable gravels or sandy gravels contain little or no
should be treated as specified in existing Army and Air
fines encompassing USCS types GP and GW.
Force publications.
2-5. Soil surface feature
2-3. Topography
Soil surface features refer to both the state of
a. Distinction between flat and hillside areas. The
compaction and degree of saturation of the soil in the
overall topography of the area should be considered as
area being considered.
either flat or hillside. Flat is defined as an average
a. Loose and dry or slightly damp. The surface
ground surface slope of 5 percent or less while hillside
consists of a blanket, 1/4 to 2 inches thick, of unbound or
refers to an average ground surface slope steeper than 6
uncompacted soil overlying a relatively firm subgrade
percent. Emphasis is placed on the fact that the entire
and ranging in moisture content from dry to slightly
topography of the area to be treated must be considered
damp.
and not specific spot localities. Spot areas can be given
b. Loose and wet or slurry. A surface condition
special attention as needed.
consists of a blanket, 1/4 to 2 inches thick, of unbound or
b. Dust control for flat and hillside areas. Dust
uncompacted soil overlying a soft to firm subgrade and
control depends on the type of traffic expected, etc.;
ranging in moisture content from wet to slurry
however, the final dust palliative selected may be
consistency. Soil in this state cannot be treated until it is
affected by the slope. For example, liquid dust control
dried to the condition defined in either paragraph above
materials may tend to flow instead of penetrate or form a
or below.
protective cover over the dusty area.
c. Firm and dry or slightly damp. The surface
condition consists of less than 1/4-inch-thick layer of
loose soil ranging in moisture content from dry to slightly
2-4. Soil type
damp overlying a bound or compacted firm soil
The soil type is one of the key features used to
subgrade.
determine which method and material should be used for
d. Firm and wet. This surface condition is similar
dust control. Soils to be treated for dust control have
to that defined in paragraph c but has a wet surface. Soil
been placed into five general descriptive groupings
in this condition cannot be treated until it is dried to the
based On the Unified Soil Classification System (USCS),
condition defined.
MIL-STD-619B.
e. Treatment ability. The soil surface feature
a. Silts or clays (high liquid limit). The relatively
described in paragraph a is acceptable for treatment for
impervious, plastic, fine-grained soils encompass USCS
dust control where no traffic or only occasional traffic is
types CH, OH, and MH.
expected.
The soil surface feature described in
paragraph c is acceptable for treatment for dust control
2-2
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