2. Test for water of plasticity.
This test finds out the amount of water required to make the clay plastic and workable. The more water the clay requires to become plastic, the finer its grain structure and hence apt to shrink more on drying.
a) Thoroughly dry the clay sample and pulverize it so that it will pass through a 30-mesh screen.
b) Weigh out 500 grams of clay onto a glass slab.
c) Fill a 500cc glass beaker with water and add the water to the clay a little at a time, mixing well after each addition.
d) Knead the clay, adding more water if necessary until it becomes smooth and of right consistency for modeling.
e) Note the amount of water which has been added to the clay.
f) Calculate the water of plasticity by using the following formula.
Percent water of plasticity = (Weight of water/ Weight of dry clay) X 100
To be contd……
