Few days ago, a Regional QAQC Manager was having a discussion with his fellow subordinates in regards to Atterberg liquid and plastic limit of soil samples. I was there to pass some documentation and he then popped out the question; "why do we roll the soil samples into 3.2mm or 1/8 inch diameter until it breaks into chunks?"

There are so many journals out there which give in-depth explanations to this event but it is hard to understand, therefore i simplified it as follows;
"Similar to steel, soil too have its plastic properties. How can we know the steel yielded its plastic limit? At the point when the steel thread losses it ductility and break. That is the main concept of plastic limit state. Simple!"