Which of the following is NOT a significance of the plasticity index?

The plasticity index is a significant measure in geotechnical engineering that reflects the plasticity characteristics of fine-grained soils, particularly clays. It is defined as the difference between the liquid limit and the plastic limit of the soil. This index plays several roles in assessing the behavior of soils under various conditions.

Indicating compressibility is a key aspect of the plasticity index. A higher plasticity index typically indicates that the soil can undergo greater deformation without breaking, suggesting that it may be more compressible. This characteristic is vital when evaluating soil behavior under load.

When it comes to the shearing resistance of soil, while the plasticity index itself does not provide a direct measure, it can influence parameters related to soil shear strength, especially in clayey soils. Soils with high plasticity indices often exhibit different shear strength behaviors compared to those with low plasticity.

The plasticity index also provides insight into the clay fraction of a binder or soil material. A higher plasticity index usually indicates a greater presence of clay minerals, which can affect other properties of the soil, such as workability and bonding with other materials.

However, the plasticity index does not measure soil permeability. Permeability refers to a soil’s ability to transmit water,