What is the boundary moisture content between semisolid and solid states of consistency called?

The boundary moisture content that differentiates between semisolid and solid states of consistency is known as the shrinkage limit. This is the point at which a soil transitions from a plastic state, where it can be molded and shaped, to a solid state, where it no longer deforms under stress.

Understanding the shrinkage limit is crucial for applications in geotechnical engineering and soil science because it helps determine the compressibility and stability of soil for construction purposes. At moisture content levels above the shrinkage limit, the soil can still be molded, but as it approaches this limit, it will begin to shrink and harden, indicating a transition to rigidity.

In contrast, the liquid limit refers to the moisture content at which soil changes from a plastic state to a liquid state, while the plastic limit marks the boundary between the plastic and semi-solid states. The plasticity index is a measure of the range of moisture content over which the soil remains plastic and is calculated by subtracting the plastic limit from the liquid limit. However, none of these directly represent the transition from semisolid to solid states as defined by the shrinkage limit.