THEORY
The liquid limit is the moisture content at which the groove, formed by a
standard tool into the sample of soil taken in the standard cup, closes for 10 mm on being given 25 blows in
a standard manner. At this limit the soil possess low shear strength.
APPARATUS
Balance ,Liquid limit device (Casagrendes), Grooving tool, Mixing
dishes, Spatula, Electrical Oven
PROCEDURE
1. About 120 gm of air-dried soil from thoroughly mixed portion of material
passing 425 micron I.S sieve is to be obtained.
2. Distilled water is mixed to the soil thus obtained in a mixing disc to form
uniform paste. The paste shall have a consistency that would require 30 to 35
drops of cup to cause closer of standard groove for sufficient length.
3. A portion of the paste is placed in the cup of LIQUID LIMIT device and
spread into portion with few strokes of spatula.
4. Trim it to a depth of 1cm at the point of maximum
thickness and return excess of soil to the dish.
5. The soil in the cup shall be divided by the firm strokes of the grooving
tool along thediameter through the centre line of the follower so that clean
sharp groove of proper dimension is formed.
6. Lift and drop the cup by turning crank at the rate of two revolutions per
second until the two halves of soil cake come in contact with each other for a
length of about 1 cm by flow only.
7. The number of blows required to cause the groove close for about 1 cm shall
be recorded.
8. A representative portion of soil is taken from the cup for water content
determination.
9. Repeat the test with different moisture contents at least three more times
for blows between 10 and40.
OBSERVATIONS
Details of the sample:.......
Natural moisture content:........ Room temperature:..............
|
Determination Number |
1 |
2 |
3 |
4 |
|
Container number |
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Weight of container |
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Weight of container + wet |
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Weight of container + dry |
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Weight of water |
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Weight of dry soil |
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Moisture content (%) |
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No. of blows |
Draw a graph showing the relationship between water content (on y-axis) and number of blows (onxaxis) on semi-log graph. The curve obtained is called flow curve. The moisture content corresponding to 25 drops (blows) as read from the represents liquid limit. It is usually expressed to the nearest whole number.
- Physical properties of minerals
- Determination of natural moisture of soil
- Determination of specific gravity of soil
- Sand replacement method
- Sieve analysis-Grain distribution
- Hydrometer analysis of soil
- Determination of liquid limit
- Determination of Plastic limit
- Determination of Shrinkage limit
- Direct shear test
- Proctor test
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