These methods are still being used to determine the Liquid Limit, Plastic Limit and Shrinkage Limit of soils, which are outlined in ASTM D4318 (Figure 1). Depending on the water content of a soil, the soil may be in one of four states: solid, semi-solid, plastic and liquid. Swedish scientist Albert Atterberg was the first person to define the limits of soil consistency for the classification of fine-grained soils and later, they were refined by Arthur Casagrande.
Thus, the boundary between each state can be defined based on a change in the clay's behavior. The consistency and behavior of a clayey soil is different as are the engineering properties at varying degrees of moisture content.
