Procedure For Determination Of Grain Size Analysis

STANDARD

OBJECTIVE

APPARATUS

Balance of capacity 15 Kg and sensitivity 1 gram.
Sieves 75 mm, 19 mm, 4.75 mm, 2 mm, 425 micron and 75 micron conforming to IS: 460 (Part -1)1978.
Non-corrodible trays.
Bucket no.

PROCEDURE
Sieve analysis of soil fraction retained on 4.75 mm IS sieve
Dry Analysis

Prepare the soil sample received from the field in accordance with IS: 2720 (Part 1)1983.
Take the sample portion retained on 4.75 mm sieve for the analysis.
The quantity of sample to be taken shall depend upon the maximum particle size contained in the soil as shown in Table.

Table: Quantity of sample required for grain size analysis

Maximum size of particle present(mm)	Weight of sample to be taken (kg)
75	60
40	25
25	13
19	6.50
12.50	3.50
10	1.50
6.	0.75
4.75	0.40

Separate the sample in to various fractions by sieving through the 100 mm, 75 mm, 19 mm and 4.75 mm IS sieves.
While sieving through each sieve agitate the sieve so that the sample rolls in irregular motion over the sieve.
Any particle may be tested to see if they will fall through but they shall not be pushed through.
Rub the material from the sieve, if necessary, with the rubber covered pestle in the mortar taking care to see that the individual particles are not broken.
Re sieve to make sure that only individual particles are retained.
The quantity taken each time for sieving on each sieve shall be such that the maximum weight of material retained on each sieve at the completion of sieving does not exceed the values shown in table.

Table: Minimum quantity of material to be retained on each sieve

Record the mass of the material retained on each sieve.
If the soil appears to contain over 5% moisture, determine the water content of the material in accordance with IS: 2720 (Part 2)1973 and correct the masses accordingly.
When the sample contains less than 5% of moisture it is not necessary to determine the moisture content for dry weight computations and make all determinations on the basis of wet weight only.
If the soil contains more than 20% of gravel particles and the fines are very cohesive with considerable amounts adhering to the gravel after separation, wash the gravel on 4.75 mm sieve using Sodium Hexarneta phosphate if necessary.

Sieve analysis of soil fraction passing 4.75 mm and retained on 75 microns IS sieve
Wet Analysis

Oven dry the portion of material passing 4.75 mm IS sieve at the temperature of 105 to 110°C.
Riffle the oven dried material so that a fraction of convenient mass of about 200 gm is obtained.
Spread out the riffled and weighed fraction in a large tray or bucket and fill with water.
Add 2 gm of Sodium Hexametaphosphate gram of Sodium hydroxide and 1 gram of Sodium carbonate per liter of water.
Thoroughly stir the sample and leave it for 24 hours soaking.
After the specified period of soaking, wash the sample thoroughly over 75 microns IS sieves.
Continue washing until the water passing sieve is substantially clear.
Care shall be taken to see that the sieves are not over loaded in the process.
Oven dry at 105 to 110°C the sample and entry the fraction retained on each sieve which is 4.75 mm, 2 mm, 425 micron , 75 micron

Dry Analysis

Conduct sieving as per the procedure described in the sieve analysis of soil fraction retained on 4.75 mm sieve except the sieves and the size of the sample.

CALCULATIONS

Calculate the percentage of soil retained on each sieve on the basis of total mass of the soil sample taken.
From these results calculate the percentage passing through each of the sieves.

REPORT

PRECAUTION

Any particle may be tested to see if they will fall though but they shall not be pushed though

DETERMINATION OF GRAIN SIZE ANALYSIS
15:2720 (Part 4/Section 3&4)1985 :

Gravel : Silt :

Sand : Clay :

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