U.S. Standard Sieve Numbers
Hydrometer
6" 4"
2"
1"
10
40
200
3/8"
100
0
P-208 Aggregate Base Course
80
20
50 mm Max
25 mm Max
60
40
37 mm Max
40
60
20
80
100
0
100
10
1
0.1
0.01
0.001
Grain Size (mm)
Gravel
Sand
Cobbles
Silt or Clay
Coarse
Fine
C'rse
Medium
Fine
b. P-208 aggregate base course.
U.S. Standard Sieve Numbers
Hydrometer
6" 4"
2"
1"
10
40
200
3/8"
100
0
P-209 Crushed Aggregate Base Course
80
20
P-208
60
40
40
60
20
80
100
0
100
10
1
0.1
0.01
0.001
Grain Size (mm)
Gravel
Sand
Cobbles
Silt or Clay
Coarse
Fine
C'rse
Medium
Fine
c. P-209 crushed aggregate base course.
Figure 1 (cont'd).
mum amount passing the no. 200 sieve for this
liquid limit of less than or equal to 25% as the
material is almost half that of the P-208. Second,
P-208 material.
both the coarse and fine portions are crushed.
Third, at least 90% of the particles by weight have
P-210 caliche base course
P-210 caliche base course is composed of cali-
two crushed faces and 100% of the particles have
one crushed face. Fourth, for cold regions, the
che, calichegravel, or calichelimestone. The
amount of material finer than 0.02 mm must be
material has a liquid limit of less than or equal to
less than 3%. The aggregates can be either clean,
35% and a PI of no more than 10%. The specified
crushed gravel, crushed stone, or crushed slag.
gradation limits for this material are shown in
This material has a lower PI (≤ 4%), with the same
Figure 1d. The P-208 gradation limits are also
3
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