To measure the plasticity of clays, several criteria have been developed, of which the one developed by Atterberg is mentioned, who first said that plasticity is not a permanent property of clays, but circumstantial and dependent on its water content. A very dry clay can have the consistency of a brick, with zero plasticity, and that same clay, with a high water content, can present the properties of a semi-liquid mud or even those of a liquid suspension. Between both extremes, there is a range of water content in which the clay behaves plastically.

The plastic limit is defined as the lowest humidity with which soil can be formed into cylinders of 3 mm diameter, rolling said soil between the fingers of the hand and a smooth surface, until the cylinders present cracks.

This property manifests itself when a loss of humidity does not lead to a change in volume. It is the moisture content between the semisolid and solid states of consistency. To obtain it in the laboratory, a portion of soil (initial humidity and initial volume known) is dried at 105 °C/110 °C and the lost humidity is calculated according to the following calculation:

Where:

W= Moisture content of the sample under test.

V= Volume of the wet sample.

Vo= Volume of the dry sample.

ɤW= Specific weight of water (1 gr/cm)

Wo= Dry weight of the sample.

To measure the plasticity of clays, several criteria have been developed, of which the one developed by Atterberg is mentioned, who first said that plasticity is not a permanent property of clays, but circumstantial and dependent on its water content. A very dry clay can have the consistency of a brick, with zero plasticity, and that same clay, with a high water content, can present the properties of a semi-liquid mud or even those of a liquid suspension. Between both extremes, there is a range of water content in which the clay behaves plastically.

The plastic limit is defined as the lowest humidity with which soil can be formed into cylinders of 3 mm diameter, rolling said soil between the fingers of the hand and a smooth surface, until the cylinders present cracks.

This property manifests itself when a loss of humidity does not lead to a change in volume. It is the moisture content between the semisolid and solid states of consistency. To obtain it in the laboratory, a portion of soil (initial humidity and initial volume known) is dried at 105 °C/110 °C and the lost humidity is calculated according to the following calculation:

Where:

W= Moisture content of the sample under test.

V= Volume of the wet sample.

Vo= Volume of the dry sample.

ɤW= Specific weight of water (1 gr/cm)

Wo= Dry weight of the sample.