3. Applications
Gradation of soil:
Well graded
Poorly graded
Proportioning of soil for mix design
Design of filters
4. Theory
If more than 50% of sample is retained on IS Sieve
4.75mm,
sample is gravel
If more than 50% of sample passes through IS Sieve
5. Theory
Coefficient of Curvature :
Cc = D30
2
D10 x D60
Between 1 -3 : Well graded gravel and sand
6. Theory
Uniformity Coefficient :
Cu = D60
D10
More than 4 - Well graded gravel
More than 6 – Well graded sand
(IS 1498 - 1970)
7. Theory
Fineness modulus (FM) :
sum of total percentage of
the
FM = sample retained on each
sieve
100
2 – 4 : fine soil
8. Apparatus
Two set of sieves:
Set1:
IS sieves of size 300mm, 80mm, 40mm, 20mm, 10mm,
4.75mm
Set 2 :
IS sieves of size
2mm,0.85mm,0.425mm,0.15mm,0.075mm
Mechanical Shaker
Brush
Oven
9. Procedure
For sample retaining on 4.75mm sieve ,
Use set 1 – 5kg sample
For sample passing through 4.75mm sieve,
Use set 2 – 1kg sample
10. Procedure
Clean all the sieves and pan properly with
brush.
Arrange the sieves according to size, with pan
at bottom and size increasing upwards.
Put the sample in top sieve and Place it in the
shaker.
Ensure that the sieves are held tightly in the
shaker.
11. Procedure
Operate the shaker for 5-10 minutes.
Weight the material retained on each sieve to
nearest 1 gram.
12.
13. Precautions
While drying, the temperature of oven should
not be more than 105°C because higher
temperature may cause permanent change in
0.075mm material.
During shaking, soil sample should not be
allowed to come out.
For plotting, percent finer should be
determined with respect to total soil taken for
