What Is GSA Test

Particle size distribution, which refers to the proportion of grains of varying sizes within a specific soil sample, is a crucial characteristic of soil. Coarse soils are typically analyzed using sieve analysis or mechanical analysis, while fine-grained soils are examined through hydrometer analysis.

Typically, a comprehensive analysis is conducted since soils usually consist of a mixture of coarse and fine particles. This combined analysis involves initially sieving the dry soil, followed by analyzing the very fine particles using either a hydrometer or pipette method after mixing them with water.

Uses Of GSA Test

To determine the Grain size analysis of soils.

GSA Test Code

IS: 2720 (Part 4 Section 3&4) 1985

Equipment & Apparatus Required

* Balance ( Capacity 15 Kg and accuracy 1 gram ( 0.1%))

* Sieves ( 75 mm, 19 mm, 4.75 mm, 2 mm, 425 micron and 75 micron ) 

* Sieve shaker

* Non-corrodible trays


After collecting soil sample it must dried in air otherwise in Hot Oven . ( The Hating Temperature must be 600C). In the presence of clods in the soil sample, they are crushed using a wooden mallet.

Particle Size Distribution of Soil

Procedure For GSA Test

  • 1000g Site Soil sample is taken in a tray. and Filled with Distilled water .Then Wash The soil sample Properly
  • Then Soil sample is Properly washed through 4.75mm IS Sieve with Distilled water till the substantially clean water comes out.
  • Retained Soil sample on IS Sieve 4.75mm should be oven-dried for 24hrs.
  • The collected soil sample is dried to constant Value of mass in the Hot oven at a temperature of 110±5C and all the IS Sieves Must be cleaned And without Damage.
  • After 24hrs Sieves The soil According To the Is 460-1962
  • The Following Sieves Are used For GSA Test 100 mm, 63 mm, 20 mm, 10 mm and 4.75 mm sieves.
  • The Taken IS sieves are arranged in descending Order sizes from top to bottom.
  • Then take dry soil sample is put onto the top of the IS sieve. 
  • Typically, a 1000 gram sample is analyzed.
  • Then The top sieve is must be covered with lid ( Closer pan )
  • Then the Bottom Sieve has a pan ( Closed pan )
  • The complete assembly is subsequently agitated either by hand with cautious vertical and circular movements or by employing a device called a sieve shaker. Typically, shaking for a duration of 10 minutes is satisfactory.
  • Then Note All All Sieve Retained Soil Weights
  • Note All The Value in Format Book
  • The Format Book Given Below


Percent retained on each sieve = Weight of retained sample in each sieve / Total weight of sample

Format Book


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