What is the Plastic Limit?

The plastic limit is defined as the moisture content at which a soil becomes plastic. It is the boundary between a soil’s solid and plastic states. ASTM D4318 is the standard test procedure for determining the plastic limit. Of course, a soil doesn’t go from solid to plastic all at once, but the standard test […]


What is the Liquid Limit?

The liquid limit of a soil is the moisture content at which: a soil changes to a liquid state. the boundary between the plastic and liquid states occurs. a soil loses its shear strength. Clearly a soil will not lose its shear strength all at once as water is being added, but there is a […]

What is the Shrinkage Limit?

The shrinkage limit of a soil is the moisture content at which: the soil is considered saturated. any loss of moisture will not result in any volume changes. The shrinkage limit is much less commonly used than the other Atterberg limits, the plastic limit and liquid limit. I have never seen the shrinkage limit reported […]