Uses OF Free swell index test

To determine free swell index of nature soil

Reference Standard

FREE SWELL INDEX TEST OF SOIL (IS-2720-PART-40-1970)

i) IS Sieve of size 425µm

ii) Oven

iii) Working Balance, with an accuracy of 0.01g

iv) 100ml capacity Graduated glass cylinder- 2 nos.,

Take two sample of 10g oven dried soil specimens, it must be passing through 425 micron Sieve
sieve.
Put each soil sample into one of the two 100 ml glass graduated cylinders.
Fill one cylinder with kerosene oil & another cylinder with Distilled water up to the 100
ml mark.
After eliminating trapped air (through gentle shaking or stirring with a glass rod), permit the sediments in both the cylinders to settle.
Ensure that the suspension reaches a state of equilibrium, maintaining it for a minimum of 24 hours.
The volume of soil in each cylinder must be measured at the end.

The free swell index of the soil is Can be calculatedby using The Following Formula :

Free swell Index, percent = [(Vd-Vk)/Vk] x100

Where

Vd = The volume of soil specimen read from the graduated cylinder containing distilled water.

Vk = The volume of soil specimen read from the graduated cylinder containing kerosene