What Is Silt Content Test of Sand?
Silt Content Test of Sand is conducted to find out the amount of silt present in the sand. Sand is one of the most important and essential building construction materials. It plays a vital role in making concrete, mortar, and another mix for construction work. Therefore, its quality and properties testing is a must before using it.
The permissible silt content in the sand must not exceed the values as specified in the IS standards. This methodology is only applicable to natural sand; it should not be used for crushed rock sand.
A good quality generally has particle size between 150 microns to 4.75 mm is sieve size and if the particle size in sand is less than this size, it is known as silt in sand. If silt content in sand exceed more than 8% which may result in reduction in bonding capacity of mix materials, also affect strength and durability of final product.
IS Code for Silt Content Test of Sand: IS 2386-2 (1963)
Silt Content of Sand Test
- 250 ml glass measuring cylinder
Procedure of Silt Content Test of Sand
- The measuring cylinder is filled with the salt-water solution (concentration of the solution will teaspoon full of common salt for every 570 ml) up to the 50 ml mark on the cylinder.
- Add sand until the level of the sand is reached up to the 100 ml mark.
- Add further salt-water solution till the 150 ml mark is reached.
- Place the palm on the mouth of the glass cylinder and shake it vigorously.
- Place the measuring cylinder on a hard leveled surface and tap it all round so that sand is leveled.
- Wait for three hours for the silt to settle on top of the sand.
- Measure the thickness of the silt layer and the height of the sand.
DETERMINATION OF SILT CONTENT
|Sr. No:||Description||Sample – 1||Sample – 2|
|1||Thickness of Sand Layer|
|2||Height of Sand + Silt|
If silt content is exceeding 3% by weight, then the washing of sand is necessary. After performing a few tests, a co-relation can be developed for silt layer thicknesses at various intervals of time. The silt content after a time interval of 10 minutes can be fixed as inspection criteria.
If the following observations taken from silt content of sand test,
Silt Layer Thickness = 1 cm
Sand + Silt Layer Height or Thickness = 10 cm
Silt Content of Sand = (1 cm / 10 cm) x 100 %
Silt Content of Sand = 1%
So, from above Test and calculations we can say that this sand has 1% silt content.
Silt content limit in sand as per IS code is 8%, so this sand we can use for construction purpose.
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