Objective:

To determine the consistency limit of soil sample by liquid limit test.

Apparatus used:

Weighing machine, Grooving tool, Porcelain evaporating dish, Casagrande device, Container etc.

 Take air dried soil in a Porcelain evaporating dish and measure it up to 120g using weighing machine.

 Place 425µm sieve on the pan and pour weighed quantity of air dried soil to the sieve then close the lid.

 Place the set of sieves in the mechanical shaker and allow to shake for 10 minutes.

 Collect the residue left on the 425µm sieve in a separate container.

 Mix the soil sample in the evaporating dish thoroughly with distilled water to form a uniform paste.

 Place a portion of the paste in the cup of Casagrande device and spread it with a few strokes of spatula.

 Using the grooving tool, cut a groove along the centre line of soil paste in the cup, so that clean sharp groove of proper dimension is formed.

 Lift and drop the cup by turning crank at the rate of 2 revolutions per second until the 2 halves of soil paste come in contact with each other by flow only. Then note down the number of blows, N.

Stop rotating the crank and
note down number of blows

0000

 Measure the weight of empty container.

Weight of empty container, (W₁) = _________ g

 Take a representative portion of soil in a container from the cup and then measure its weight for moisture content determination.

Weight of container + wet soil, (W₂) = _________ g

 Place the container with wet soil sample in the oven for 24 hours at 115°C temperature.

After 24 hours

 Measure the weight of the dry soil sample.

0.003

Weight of container + dry soil, (W₃) = _________ g

 Observations:

 Variables used in calculation:

 Calculations:

Repeat the procedure from step 6 - 13

 Observations:

 Calculations:

Plastic limit of given soil sample