What Does Atterberg Limits Mean?
Atterberg limits were found by Albert Atterberg and defined the limits of soil consistency for the classification of fine-grained soils. Soil can be in four states depending on its water content, namely solid, semi-solid, plastic and liquid.
The American Society for Testing and Materials (ASTM) D 4318 outlines the methods used to determine the liquid limit (LL), plastic limit (PL), and shrinkage limit (SL) of soil using the Atterberg limits test.
Trenchlesspedia Explains Atterberg Limits
The Atterberg limits test is a classification test and is performed to aid in the classification of soil and its plasticity characteristics. It evaluates the shrink/swell potential of near-surface soil and can be used to distinguish between silt and clay and its different types.
It gives the shrinkage limit, plastic limit, and liquid limit of the soil sample. An Atterberg limits test is performed only on the soil fraction that passes through sieve No. 40.
The Atterberg limits test provides the following limits:
Liquid limit (LL) - the moisture content at which fine-grained soil ceases to slow like a liquid.
Plastic limit (PL) - the moisture content at which a fine-grained soil c.annot be remolded without cracking
Shrinkage limit (SL) - the moisture content at which a fine-grained soil does not change the volume on drying; the moisture loss is compensated by air that enters its pores.