Parameters for Liquid Limit, Plastic Limit and Plasticity Index

Typical parameters for liquid limit (w_L), plastic limit (w_P) and plasticity index (I_P) of several soil types, can be found in the table.

The plasticity index I_P is illustrated in the plasticity diagram subject to the liquid limit w_L.

Table:

Typical parameters for w_L, w_P and I_Pof selected types of soil [Schmi96]

Soil type	Liquid limit wL [%]	Plastic limit wP [%]	Plasticity IP
Fine sand	20 to 40	15 to 20	5 to 25
Silt	25 to 50	20 to 23	4 to 20
Clay, highly plastic	60 to 85	20 to 35	33 to 55
Silt and Clay, organic	45 to 70	30 to 45	10 to 30

Image:

Plasticity diagram according to Casagrande with soil groups to DIN 18196 [DIN18196:1988] [DIN18196:2004]