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For determination of liquid limit in laboratory the soil sample passing through............. IS sieve is used
0.075┬аmm
0.150┬аmm
0.425┬аmm
0.600┬аmm
0.425┬аmm
The liquid limit test, defined by the Casagrande apparatus, requires the soil sample to be prepared by removing particles larger than 0.425 mm. This specific size corresponds to the IS 425 micron sieve, ensuring that only the fine-grained fraction (silt and clay) contributes to the plastic behavior measured during the test.
The liquid limit test, defined by the Casagrande apparatus, requires the soil sample to be prepared by removing particles larger than 0.425 mm. This specific size corresponds to the IS 425 micron sieve, ensuring that only the fine-grained fraction (silt and clay) contributes to the plastic behavior measured during the test.
wLтАЛ=w├Ч(N/25)0.121 тАФ Empirical relation for liquid limit at N blows
The liquid limit represents the transition point between liquid and plastic states of soil, which is a property primarily associated with clay minerals. Larger particles (sand and gravel) do not possess significant cohesive properties and would introduce errors in the determination of the groove closure mechanism; hence, they are removed via the 0.425 mm sieve.
The 0.425 mm sieve is the boundary between the sand fraction and the fine-grained (silt/clay) fraction.
The test is performed on air-dried or oven-dried soil that has passed through the 425 micron sieve.
Liquid limit is one of the Atterberg limits used for soil classification in the Unified Soil Classification System (USCS) and IS classification.
IS 2720 (Part 5) describes the standard procedure for the determination of liquid and plastic limits.
Ensures consistency in soil samples by standardizing particle size.
Focuses the test on the active clay mineral fraction.
Time-consuming if the soil contains a high percentage of gravel and sand.
Requires careful preparation to avoid breaking down particles.
Soil classification (CH, CL, MH, ML types).
Estimation of soil shear strength and compressibility.
Assessment of soil suitability for road subgrade and embankments.
The 0.075 mm sieve is used for hydrometer analysis and determining the percentage of fines.
0.425 mm is exactly 425 microns, standard for Atterberg limit testing.
Incorrect options (0.075, 0.150, 0.600 mm) do not represent the standard requirement for liquid limit preparation.
C is correct тАФ The soil sample used for the liquid limit test must pass through a 0.425 mm IS sieve to isolate the fine-grained soil particles.
Always distinguish between the 0.075 mm sieve (used for identifying fines in soil classification) and the 0.425 mm sieve (used for preparation in plasticity tests like liquid and plastic limits).