6.2. Plasticity Chart

Try these first

1. 1.

   What is plasticity in soil?

   Hint

   Think about how clay behaves when wet.

2. 2.

   Define the plasticity index.

   Hint

   Consider it as the difference between liquid and plastic limits.

3. 3.

   What is the formula for the 'A' line on the plasticity chart?

   • I_P = 0.73(W_L - 20)
   • I_P = 0.5(W_L + 10)
   • I_P = 0.3(W_L - 30)

   Hint

   Think about how we derived it during class.

4. 4.

   True or False: A higher plasticity index indicates a more plastic soil.

   • True
   • False

   Hint

   What does plasticity index measure in terms of soil behavior?

5. 5.

   Given a soil sample measured: Liquid Limit = 62%, Plastic Limit = 32%, and moisture content = 48%. Determine its classification and liquidity index.

   Hint

   Don’t forget to apply the index formulas correctly to classify the soil.

6. 6.

   A researcher finds a soil with 45% liquid limit, 25% plastic limit, and 80% clay content. Calculate its activity and suggest possible implications if used for construction.

   Hint

   Use the ratios properly to assess the suitability of the soil.