SILT TEST : AGGREGATE (FINE AND COURSE AGGREGATES)
Relevant IS Code – IS: 2386 (Pt. – III) – 1963
1. Take a 250 ml jar and fill clean water up to about ¾th height of the
bottle.
2. Add a pinch of salt (Only a tea spoonful not a table spoonful) &
stir & shake vigorously so that salt dissolves.
3. Add sand up to about half the height of the bottle.
4. Shake vigorously so that silt goes into suspension.
5. Rotate cylinder till FA is level.
6. Keep aside ensure that the cylinder is level.
7. Take readings X & Y after 10 minutes & 3 hours.
8. Establish co-relationship between 10 minutes & 3 hours.
9. Silt content > 3% by weight (IS: 383 – 1970)
> 8%
by Volume
10. Generally if the silt content comes to 20% or less after 10 minutes
if settles down 8% or less after 3 hours by volume. This has been decided by
initially carrying out number of trials. Acceptable limits for sand are as
follows.
a
|
Silt
|
8% after 3 hours
|
20% after 10 min
|
||
b
|
Shingle
(Particles > 4.75 mm size)
|
28%.
|
There should be no clay lumps & shale material in the sand.
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