The liquid limit test is carried out using Casagrande Apparatus. It is used for determining the liquid limit of the soil.
Equipment for Liquid Limit Test on Soil
1.Casagrande’s liquid limit device
2.Grooving tools of both standard and ASTM types
4.Evaporating dish or glass sheet
6.425 micron IS sieve
7.Weighing balance having an accuracy of 0.01g.
– The liquid limit device is used for determining the liquid limit.
– Take a soil sample passing through the sieve of 0.425 mm sieve. Make a paste of soil.
– Place it on the metal brass cup of liquid limit device and level horizontally using a knife or spatula.
– Divide the soil into two portions using the grooving tool.
– Rotate the liquid limit device at the rate of 2 revolutions per second.
– Record the number of blows to close the bottom of the groove through a distance of 13 mm.
– Determine the water content using Oven Drying Method.
– Water content at 25 no. of blows is taken as the liquid limit device.
– The test should be done for at least 4 times.
Datasheet for Liquid Limit Test
|Sl. No.||Observations and Calculations||Determination No.|
|1||Number of blows (N)|
|2||Water content can No.|
|3||Mass of empty can (M1)|
|4||Mass of can + wet soil (M2)|
|5||Mass of can + dry soil (M3)|
|6||Mass of water = M2 – M3|
|7||Mass of dry soil = M3 – M1|
|8||Water content = w = [(6) / (7)] x 100|
Result of Liquid Limit Test
Draw a flow curve between log N and w.
Liquid limit (for N=25) =