atterberg limits

• 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.