# Plasticity Index

Written by Jerry Ratzlaff on . Posted in Geotechnical

Plasticity index, abbreviated as PL, is scaling the natural moisture content of a soil sample in which soil remains in a plastic state while passing from a semisolid state to a liquid state.

## formulas that use plasticity Index

 $$\large{ PL = LL - PL }$$

### Where:

$$\large{ PL }$$ = plastic limits

$$\large{ LI }$$ = liquidity index

$$\large{ LL }$$ = liquid limits