This standard specifies the requirements for the liquid limit apparatus used for determining the liquid limit of soils. It covers the material, dimensions, and constructional details of the components, including the brass cup, hard base, cam mechanism, and grooving tools.
liquid limit apparatus for soils
Quick Reference Values
Height of fall of cup10 ± 0.2 mm
Mass of cup with suspension200 ± 20 g
Speed of cam rotation2 revolutions/second (120 rpm)
Base hardness (Shore D)Not less than 80
Cup materialBrass
Grooving tool (Casagrande) tip width2.0 mm
Practical Notes
The hardness of the ebonite base is a critical parameter for obtaining accurate results and it degrades over time. It should be checked periodically.
The 10mm height of drop must be calibrated frequently using the gauge on the grooving tool's handle or a separate block.
The point of contact between the cup and base should be kept clean and free from soil particles to ensure a consistent drop.