What is Bulking of Sand and its effect

Dnyan Deshmukh

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Sep 7, 2017
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Bulking of Sand
Bulking of sand is nothing but the change in volume of sand due to presence of water / moisture in it.
Finer the sand more it tend to change the volume when water is present in it and vice a versa.

The properties of sand available at each local location may have different properties including its gradation.
To arrive at what bulkage happens in particular sand in your area, one should need to do some experiments with types of sand available.
In order to do that one should get the sand sample and make it oven dry before starting experiment.

Take a dry sand and loosely fill it in the cylindrical volume container of known volume (you can use any shape, not necessary to use cylindrical only)
Measure it weight and calculate dry loose bulk density.
Do add water incrementally 1%, 2%, 3% and record the loose density at each % water addition.

One time will come beyond which any addition of water will tend to decrease in volume (effect of bulkage start reducing)
After that find the saturation point above which addition of water does not have any effect in change of volume.

This test result will form a basis for checking the bulkage by finding water / moisture content in it.

Today most of the concrete produced by weight batching, so moisture correction is required for mix proportioning.

If you are receiving sand in volumetric measurements, this will help you to pay exact amount for what you are getting.

If the dispute arises between supplier and customer, best way to do measurement of truck is saturating the sand in truck by pouring water in it, this nullify the effect of bulking in sand.

Below is the sample calculation attached for your reference, it may or may not be relevant for you.

bulking of sand at various moisture content.png
 

Dnyan Deshmukh

Eternal Member
Staff member
Sep 7, 2017
2,427
4,147
Pune
It may cause failure due to change in proportion of ingredient in concrete when volume batching is done.

It will help you and your company to loose money on sand when you purchase it on volume basis and does not check bulkage of it.

In mortars, it does not affect the strength but leads to over consumption of cement.

So in concrete only when done by volume batching, it can create trouble for you.

Rest places it will increase your construction cost.
 
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