Figure 15-30.-Hand-operated sieve shaker.
The hand-operated shaker is shown in figure
15-30.
SIEVE ANALYSIS, DRY.— The minimum
sample weight required for a sieve analysis is
dependent upon the maximum particle size in the
sample as follows:
Maximum particle size Minimum dry weight
(sieve opening)
of test specimen
3 in.
6,000 g
1 1/2 in.
3,000 g
3/4 in.
1,500 g
3/8 in.
600 g
No. 4
200 g
Samples that contain cohesive soil, which
forms hard lumps, must be prewashed. This pro-
cedure is described later. Other samples are
analyzed DRY by the following procedure:
1. Oven-dry the sample.
2. Break up lumps. For coarse material, use
a rolling pin on a clean, hard, smooth surface.
For fine material, use a mortar and pestle (usually
a part of the laboratory apparatus). Take care not
to crush individual grains. The object is to
separate aggregations of clustering grains.
3. Weigh the sample.
4. Select and weigh the sieves and pan to be
used in the test. The sieve selection varies
according to the type of soil being tested. The
following is a selection commonly used:
3 in. (76.2 mm)
No. 10 (2.00 mm)
1 1/2 in. (38.1 mm) No. 20 (1.21 mm)
1/2 in. (12.7 mm)
No. 40 (0.42) mm
3/8 in. (9.52 mm)
No. 100 (0.149 mm)
No. 4 (4.76 mm)
No. 200 (0.074 mm)
Stack (nest) the sieves one on top of the other
such that the largest sieve is on top. The coarsest
sieve actually recorded is the next above the first
one that retains any material. The weight recorded
as retained on this sieve is 0 g; the weight
recorded as passing it is the total weight of the
sample.
5. Place the sieve pan under the stack of
sieves; place the total sample in the top sieve and
shake. The shaking interval depends on the
amount of fine material. Five minutes is usually
enough for most coarse-grained soils, and 15 min
is enough for most fine-grained soils.
6. Remove the sieves from the shaker. Start-
ing with the first to retain any material, carefully
weigh each sieve with the retained material. Sub-
tract the weight of the sieve from the combined
weight of the sieve and material to determine the
weight of the material retained on each sieve.
Finally, determine the weight of the material that
reached the pan; that is, that passed the No. 200,
or finest, sieve.
Enter the results on a data sheet like the one
shown in figure 15-31. In this analysis, all the
material (359. 1 g) passed the 3/8-in. sieve; none
was retained on this one. The No. 4 retained
51.0 g. This means that 308.1 g (359.1 – 51.0)
passed this sieve. You can see how the weight pass-
ing was determined from the weight retained in
each subsequent case. In column d, the percent
passing is computed for each sieve by multiply-
ing the weight passing by 100 and dividing the
result by the total weight of the sample.
15-22
