TM
5-822-14/AFJMAN
32-1019
Table 3-7. Emulsified asphalt requirements
Pounds of Emulsified Asphalt per 100 pound of Dry Aggregate at Percent Passing No. 10 Sieve
Percent Passing
No. 200 Sieve
<50
60
70
80
90
100
0
6.0
6.3
6.5
6.7
7.0
7.2
2
6.3
6.5
6.7
7.0
7.2
7.5
4
6.5
6.7
7.2
7.7
7.0
7.5
6
6.7
7.0
7.2
7.5
7.7
7.9
8
7.0
7.2
7.7
7.9
8.2
7.5
10
7.2
7.5
7.7
7.9
8.2
8.4
12
7.5
7.7
8.4
8.6
7.9
8.2
14
7.2
7.5
7.7
7.9
8.2
8.4
16
7.2
7.0
8.2
7.5
7.7
7.9
18
6.7
7.0
7.2
7.5
7.7
7.9
20
6.5
6.7
7.0
7.2
7.5
7.6
22
6.3
6.5
7.5
6.7
7.0
7.2
24
6.0
6.3
6.7
7.2
6.5
7.0
25
6.2
6.4
6.9
7.1
7.3
6.6
modified or another type of bituminous material
desired results. The design cement content is
arrived at following procedures for cement stabi-
should be used. Poorly graded materials may be
lized soils presented in paragraph 3-1.
improved by the addition of suitable tines contain-
b. Lime-asphalt. Lime can be used as an initial
ing considerable material passing the No. 200
additive with asphalt as the primary stabilizer.
sieve. The amount of bitumen required for a given
The main purpose of lime is to improve workabil-
soil increases with an increase in percentage of the
ity characteristics and to act as an anti-stripping
liner sizes.
agent. In the latter capacity, the lime acts to
3-5. Stabilization with Lime-Cement and Lime-
neutralize acidic chemicals in the soil or aggregate
Bitumen. The advantage in using combination
which tend to interfere with bonding of the as-
phalt. Generally, about 1-2 percent lime is all that
stabilizers is that one of the stabilizers in the
is needed for this objective. Since asphalt is the
combination compensates for the lack of effective-
primary stabilizer, the procedures for asphalt sta-
ness of the other in treating a particular aspect or
bilized materials as presented in paragraph 3-4
characteristics of a given soil. For instance, in clay
shall be followed.
areas devoid of base material, lime has been used
jointly with other stabilizers, notably portland
3-6. Lime Treatment of Expansive Soils. Ex-
cement or asphalt, to provide acceptable base
pansive soils as defined for pavement purposes are
courses. Since portland cement or asphalt cannot
those that exhibit swell in excess of three percent.
be mixed successfully with plastic clays, the lime
Expansion is characterized by heaving of a pave-
is incorporated into the soil to make it friable,
ment or road when water is imbibed in the clay
thereby permitting the cement or asphalt to be
minerals. The plasticity characteristics of a soil
adequately mixed. While such stabilization prac-
often are a good indicator of the swell potential as
tice might be more costly than the conventional
indicated in table 3-8. If it has been determined
single stabilizer methods, it may still prove to be
that a soil has potential for excessive swell, lime
economical in areas where base aggregate costs
treatment may be appropriate. Lime will reduce
swell in an expansive soil to greater or lesser
are high. Two combination stabilizers are con-
sidered in this section: lime-cement and lime-
degrees depending on the activity of the clay
minerals present. The amount of lime to be added
asphalt.
a. Lime-cement. Lime can be used as an initial
is the minimum amount that will reduce swell to
acceptable limits. Procedure for conducting swell
additive with portland cement or the primary
stabilizer. The main purpose of lime is to improve
tests are indicated in MIL-STD 621 Method 101 or
workability characteristics mainly by reducing the
ASTM D 1883. The depth to which lime should be
plasticity of the soil. The design approach is to add
incorporated into the soil is generally limited by
enough lime to improve workability and to reduce
the construction equipment used. However, 2 to 3
feet generally is the maximum depth that can be
the plasticity index to acceptable levels. The de-
treated directly without removal of the soil.
sign lime content is the minimum that achieves
3-8
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