Plasticity Index and Plastic Limit of Soil

no but here are the links

http://www.google.co.uk/search?q=plasticity+index+of+soil&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&redir_esc=&ei=lJW8S465AobAmQOt2ri3CA

the most obvious answer is that any fine soil contaminate will alter the way the soild behaves, as silt will not have any sharp endges it will i think make the soil it is mixed with, more fluid under certain conditions