1. To find the water content corresponding to the behavior change between the liquid and the plastic state of a silt or clay. 2. To find the water content corresponding to the behaviour change between the plastic and semisolid states of a silt or clay. APPARATUS
Test sieve of size 425um and 2 mm, receiver, sharp knife, 2 palettes knife, an airtight container, glass plate, wash bottle containing distilled water, glass breaker, glass stirring rod and length of rubber tubing for connection to the water supply. Theory
The term plasticity is applied to silt and clay indicates an ability to be rolled and molded without breaking apart. The Atterberg Limit is defined as the water content corresponding to the different behaviour condition of silt clays. Atterberg Limit is defined as the water content corresponding to the different behaviour condition of silt clays. Atterberg Limits only refer to the liquid limit (LL), plastic limit (PL) and shrinkage limit (SL). Liquid Limit is defined as the water content at which pat soil, cut by a groove of standard dimensions, will flow together for distance of 12.7 mm (0.5 in) under a impact of 25 blows in standard liquid limit device (ASTM D 4318-98, 2000). Plastic Limit is defined as the water content at which a silt or clay will just begin to crumble when rolled into a thread approximately 3.2 mm ( 1/8 in ) in diameter ( ASTM D 4318-98,2000 ). Shrinkage Limit is defined as the water content at which any further reduction in water content will not result in a decrease in volume of soil mass ( ASTM D 427-98 or D 4943-95,2000 ). For the liquid test, we have 2 method of testing which are : 1. Cone penetration method
2. Casagrande method
A) Liquid limit test :
1. Take a sample of the soil of sufficient size to give a test specimen weight at least 400g which passed the 425 um test sieve. 2. Transfer the soil to a flat glass plate. Add distilled water and mix thoroughly with 2 palettes...