Casagrande method in mechanical form is known as liquid limit Method and has been in use for soil mechanics for a number of years. The liquid limit data of soils is useful to correlate mechanical properties of soil such as compressibility and lower sheaaar strength. Liquid Limit is the water content at which soil passes from zero strength to an infinitesimal strength, hence the true value o fliquid limit can not be determined. For determination purpose, liquid limit is that water content at which a part of soil, cut by a groove of standard dimensions, will flow together for a distance of 1.25cmunder an impact of 25 blows in a standard liquid limit apparatus. The soil at the water content has some strength which is about 0.17 N/cm.sq.(17gms/sq.cm.) At this water content water just passes from liquid state to plastic state.
Specifications: It consists of a brass cup held on an adjustable basket. The cup can be adjusted for a fall of 1 cmand can be raised or dropped on a rubber baseof standard hardness by cam acion. Complete with one casagrande grooving tool, one ASTM Grooving tool and a heigh gauge block.