The Atterberg limit test is a fundamental geotechnical engineering test that measures the critical moisture content of fine-grained soils, such as clay and silt.

 The Atterberg limit test is a fundamental geotechnical engineering test that measures the critical moisture content of fine-grained soils, such as clay and silt. The test determines the liquid limit, plastic limit, and shrinkage limit of a soil, which are used to assess the soil's consistency, workability, and potential for volume change: 

Liquid limit (LL): The maximum water content a soil can have before becoming a liquid 

Plastic limit (PL): The minimum water content at which a soil can no longer be remolded without cracking 

Shrinkage limit (SL): The water content at which further loss of moisture will not result in any more volume reduction 

The Atterberg limit test is important because it helps predict how soils will perform as construction materials, and can influence everything from foundation design to project stability. 

Albert Atterberg created the Atterberg limits in 1910, and Arthur Casagrande refined them in 1927.