THE COOPER UNION
Albert Nerken School of Engineering
SOIL MECHANICS LABORATORY
Experiment No. 4 - Liquid and Plastic Limits of a Soil
Name:

Date:

Group No.:
Members:

Location: Depth:
Boring: Elevation:
Sample: Description:
Grooving Tool:

Variables:

wl = Liquid Limit, %

wp = Plastic Limit, %

wn = Natural Moisture Content, %


Formulae:

     1.     Plastic Index  =  Ip  =  wl - wp

     2.     Flow Index   =  If  =  slope of flow curve

     3.     Liquidity Index  =  Il  =  wn - wp / Ip

     4.     Activity = A = Ip / (% finer than two microns in the -40 sieve fraction)


TABLE 1. - Liquid Limit

Trial No. 1 2 3 4 5 6 7 8
Weight of Container, gm.
Weight of Container & Wet Soil, gm.
Weight of Container & Dry Soil, gm.
Weight of Moisture, gm.
Weight of Dry Soil, gm.
Moisture Content, %

No. of Blows

TABLE 2. - Plastic Limit

Trial No. 1 2 3 4 5 6 7 8
Weight of Container, gm.
Weight of Container & Wet Soil, gm.

Weight of Container & Dry Soil, gm.
Weight of Moisture, gm.

Weight of Dry Soil, gm.
Moisture Content, %
Avg. Plastic Limit

TABLE 3. - Summary of Test Constants

Liquid Limit

Plastic Limit
Plastic Index
Flow Index
Liquidity Index
Activity