Atterberg limits are a set of measures used to determine the consistency and nature of fine-grained soils, such as clay and silt. These limits are based on specific moisture content values, and can be used to distinguish between different types of clay and silt

 Atterberg limits are a set of measures used to determine the consistency and nature of fine-grained soils, such as clay and silt. These limits are based on specific moisture content values, and can be used to distinguish between different types of clay and silt. 

The Atterberg limits include: 

Liquid limit (LL)

The maximum amount of water a soil can contain before it turns into mud

Plastic limit (PL)

The minimum amount of water a soil can contain before it behaves in a plastic manner, meaning it can be molded

Shrinkage limit (SL)

The water content at which further loss of moisture will not cause any more volume reduction

Plasticity index (PI)

The range of moisture contents at which the soil remains plastic, calculated by subtracting the plastic limit from the liquid limit (PI = LL - PL)

Atterberg limits are used to classify fine-grained soils, and can also be used to predict the engineering properties of these soils. For example, the plasticity index is a useful indicator of a soil's potential to resist liquefaction. 

The Atterberg limits were developed by Albert Atterberg in 1910 and refined by Arthur Casagrande in 1927.