Question

If 24 students run 24 Casagrande Tests and 24 Thread Rolling Tests, how many different Plasticity Indexes will we most likely see and why?

Answer 1

We will get 24 different plasticity indexes.

Casagrande test is used to find the Liquid limit of the soil. Each student will get a different value of liquid limit as no two students have the same accuracy. So we have 24 distinct liquid limits.

Thread rolling test is used to find the plastic limit of soil. Plastic limit is defined as minimum water content at which 3 mm diameter thread can be formed without cracks. Similarly we will have 24 distinct plastic limits.

Now, Plasticity index = Liquid limit - Plastic limit . Each student will find a different plasticity index from the liquid and plastic limit values calculated by him/her from the two tests above.

So we will have 24 plasticity indexes.