Ch. 25] PLASTICITY 467 



TABLE 2 

 The Plastic and Liquid Limits and Plastic Index of Some Clay Minerals 



[After White (1947)] 



1 The plastic limit is the water content at which the clay can just be rolled into 

 a thin thread. The liquid limit is the water content at which the mass just begins 

 to flow. The water content is based on water loss at 110° C. For details of the test 

 see Casagrande (1932). 



TABLE 3 



Water of Plasticity x for Various Clay Minerals 



[After White (1947)] 



Clay Minerals 

 Kaolinite 

 Illite 



Montmorillonite 

 Halloysite 

 Attapulgite 



Water of Plasticity 



8.89- 56.25 



16.95- 38.5 



82.9 -250.0 



33 - 50 



92. 6± 



1 The water of plasticity is the percent of water based on water loss at 110° C 

 required to develop a workable plastic state. 



