Silt Content Test for Sand (Fine Aggregate)

Sand plays the vital role in every part of the construction (concrete, plastering, brickwork, flooring).

So it is essential to ensure that we are using good quality of sand.

Why we measure the Silt Content in the sand?

Silt content is a fine material which is less than 150 micron. It is unstable in the presence of water.

It is unstable in the presence of water. If we use silty sand for bonding, it will reduce the strength and cause rework.

You may be experienced this while plastering for a roof where the mason tries to plaster the mortar where it gets continually peel off.

Excessive quantity of silt, not only reduces the bonding of cement and fine aggregates but also affects the strength and durability of work. You can check out this article for silt and clay properties.

In the field, we have to conduct silt test for every 20 Cum of sand. This may vary.

Silt Content Test for Sand

Objective250 ml Measuring Cylinder

Find out silt content in sand (fine aggregate)

Apparatus required

  • 250 ml measuring cylinder
  • Water
  • Sand & Tray

Test Procedure

  • First, we have to fill the measuring cylinder with 1% solution of salt and water up to 50 ml.
  • Add sand to it until the level reaches 100 ml. Then fill the solution up to 150 ml level.
  • Cover the cylinder and shake it well (as shown in video)
  • After 3 hours, the silt content settled down over the sand layer
  • Now note down the silt layer alone volume as V1 ml (settled over the sand)
  • Then note down the sand volume (below the silt) as V2 ml
  • Repeat the procedure two more times to get the average

Silt Content Formula

The permissible Silt content in sand percentage is only 6%.

Silt Content test sand report

1Volume of Sample (V1) ml
2Volume of Silt (V2) ml
3Percentage of Silt
(V2/V1) * 100

You can also download this observation sheet in PDF Format

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