- 1. ATTERBERG LIMITSLiquid limit test: A soil is place in the
grooving tool whichconsists of a brass cup and a hard rubber base.
Agroove is cut at the center of the soil pat using astandard
grooving tool. The cup is then repeatedlydrooped from a height of
10 mm until a grooveclosure of 12.7 mm. The soil is then removed
and itsmoisture content is determined. The soil is said tobe at its
liquid limit when exactly 25 drops arerequired to close the groove
for a distance of 12.7mm ( one half of an inch)
2. Plastic limit test: A soil sample is rolled into threads
until itbecomes thinner and eventually breaks at 3 mm. it isdefined
as the moisture content in percent at which thesoil crumbles when
rolled into the threads of 3.0 mm. Ifit is wet, it breaks at a
smaller diameter; if it is dry itbreaks at a larger diameter.
Shrinkage limit test: It is performed in the laboratory with a
porcelaindish approximately 45 mm in diameter and about 12.7mm
high. The dish is completely filled with wet soil. Themass and
volume of the wet soil is then recorded. Thedish is then oven
dried, then the mass and volume ofthe oven dried soil is also
recorded.