2.3.2. Plasticity Index (PI)

Try these first

1. 1.

   What is the formula for calculating the Plasticity Index?

   Hint

   Think about what two limits are being compared.

2. 2.

   Is a higher Plasticity Index usually desirable for pavement construction?

   Hint

   Consider the behavior of soil with moisture changes.

3. 3.

   What does a high Plasticity Index indicate about soil?

   • It is stable
   • It is expansive
   • It is dry

   Hint

   Think about how moisture affects soil volume.

4. 4.

   True or False: Low Plasticity Index soils are ideal for pavement construction.

   • True
   • False

   Hint

   Reflect on the role of stability in construction.

5. 5.

   A civil engineer has two soil samples: one with LL of 45% and PL of 20% and another with LL of 30% and PL of 15%. Calculate the PI for both and discuss their implications for road construction.

   Hint

   Remember, a higher PI often indicates more problems for subgrade support.

6. 6.

   Considering a specific region prone to heavy rainfall, suggest modifications for construction practices if high PI soils are detected.

   Hint

   Focus on methods to enhance soil performance under moisture stress.