Finding Out Free Swell Index Of Soil
IS: 2720(Part 40)-1985
1.Oven(1000C to 2200C minimum)
2.Balance 500 grams with 0.01 g accuracy
3.Sieve 425 micron
4.Two glass cylinder having 100 ml capacity
PREPARATION OF SAMPLE
The soil passing through 425 micron IS sieve is used in this test.
1.Take 2 nos sample of 10 g oven dried soil sample passing through 425 micron IS sieve .
2.Each soil sample is poured into each of the two glass graduated cylinders having 100 ml. capacity.
3.Fill kerosene oil into one glass graduated cylinder and fill distilled water up to the 100 ml mark into another cylinder.
4. Remove entrapped air, if any , by stirring with suitable means.
5.Allow about 24 hours time to soil sample to attain equilibrium state of volume without any further change in the volume of the soils.
6. Take the reading of each cylinder , after completion of 24 hours the final volume of soils .
Formula for free swell index of the soil is :
Free swell index of soil, percent = ((Vd-Vk) / Vk)*100
Vd = The volume of soil specimen reading from the graduated cylinder containing distilled water.
Vk = The volume of soil specimen reading from the graduated cylinder containing kerosene oil
The free swell index of soil is reported to the nearest whole number.