Silt Content Test For Sand

Sand is considered as the fine aggregate in the construction field. Sand is one of the component of concrete which is essential for binding the other contituents like coarse aggregates,cement. Being a civil engineer, i always recommend that sand should be screened first before mixing it with coarse aggregates and cement to form a solid concrete mass. But it will involve some extra cost in screening of sand.Screened sand should be used for construction works for better quality works.

Silt Analysis is very important for testing the presence of silt in the sand. Fine material less than 150 microns is found in sand is called silt. Excessive amount of silt reduces the strenght of concrete.The high amount of silt in the sand can be harmful to the strength and durability of the concrete. The presence of greater silt content (> 6%) in the sand reduces the bonding capacity of the raw material and affects the strength and durability of the work. Silt content testing is recommended for every 20 - 25 mof sand.

Apparatus and Equipments:

1. Graduated cylindrical jar.

2. Water

3. Pinch of salt

4. Sand Specimen.


1.100 ml of the measuring jar is filled with sand.

2. Water is poured until it reaches 150 ml of the jar.

3. Then a pinch of salt is added.

4. The jar is shaken vigorously by closing the mouth of the jar with pam of your hand and rotating it up and down repeatedly.

5. The mixture is then allowed to settle for about 3 to 4 hours by placing the jar on a stable and flat surface.

6. Silt in the sand will settle over the sand in the jar.

7. Then pay attention to the amount of silt layer in millimeters as V1.

8. Note the amount of sand as V2 in millimeters below.

9. Repeat the process by taking two more samples and enter their value in the observation sheet.

10. The average of the three readings is taken as the final result.

Permissible value :

The permissible Silt content in sand percentage is only 6%,hence the sand sample is ok and can be used for construction purposes. 

Percentage of Silt Content = (V1/V2) x 100

V1 – Volume of silt layer

V2 – Volume of sand layer


Measurement Jar

Note: For better understanding,i will provide you with some reading that i have conducted at construction site.These reading will vary depending upon the quality of sand. 

so, you can see the reading here:-


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