The Shrinkage Limit of a soil is defined as the moisture content after which any further reduction of moisture does not cause volume reduction. The shrinkage of clayey soil can be very significant. A fully saturated soil specimen is allowed to dry in free air and its volume is measured repeatedly by immersing in a mercury bath. From the data obtained from this test, Shrinkage Limit, Shrinkage Ratio, Shrinkage Index and Volumetric Shrinkage can be calculated. The choice of puddle-clay material is often governed by the results obtained from this test.
Ref. Standards IS: 2720 (Part 6), 10077, ASTM : D 427, BS : 1377, AASHTO T-92