How to calculate bulking of sand

If dry sand comes in contact with the atmospheric moisture, bulking in sand happens. If moisture content exists, a thin layer is developed around sand particles.

This layer produces the force to shift particles a side each other. It leads to increasing the volume of sand.

If too much moisture content is present in the sand, the functionality of concrete is raised but the strength and longevity of concrete is reduced significantly.

According to IS code, existence of 4% of moisture content in sand enhances 25% of its volume.

The expanse of sand bulking is based on the grading of sand. Finer sand has more bulking as compared to the medium and coarse sand. Therefore, bulking in sand is greater for fine sand and less for coarse sand. If bulking is raised in sand, concrete mix is affected and behaves roughly at the time of placement.

Moisture content under 5% is recommended for construction purposes.

To work out the bulking of sand, percentage of moisture content in the sand, some water is added to raise the moisture content of sand. Because of this, the sand particles stuff nearer to each other and the bulking of sand is reduced slowly. So, it allows for determining the genuine volume of sand (dry sand). Therefore, the dry sand and completely saturated sand contains the same volume.

With the help of following procedure, percentage of bulking is obtained:-

1. Choose a simple container and include 2/3 part of sand in it.
2. Calculate the perfect height of sand with the scale and note it down. (H1)

3. Now pack the container upto 2/3 part with water. (similar height of sand)
4. Now include the measured sand to the container and wait for some time to settle down.
5. Now compute the height of Sand in water. (H2)

Article Source: civilread.com