Plastic Index

Plastic index, abbreviated as PI, also called plasticity index, a dimensionless number, is the water content at which the soil changes from semi-solid state to solid state.

 

plastic Index formula
\(\large{ PI =  LL - PL   }\)
Symbol	English	Metric
\(\large{ PI }\)  =  plastic index	\(\large{dimensionless}\)
\(\large{ LL } \) = liquid limit	\(\large{dimensionless}\)
\(\large{ PL } \) = plastic limit	\(\large{dimensionless}\)