There are three important Atterberg limits: shrinkage limit (SL), plastic limit (PL), and liquid limit (LL). The shrinkage limit is the water content at which the volume of the soil starts to increase.
Why Atterberg test is done?
The Atterberg limits test is a classification test used to determine the moisture content at which fine-grained clay and silt soils transition between the different phases. The test for Atterberg limits is performed on the fraction of soil that will pass through a No. 40 or 425µm or 0.425mm sieve as per ASTM D 4318-00.
What are Atterberg limits used for?
Atterberg limits tests establish the moisture contents at which fine-grained clay and silt soils transition between solid, semi-solid, plastic, and liquid states.
How do you perform an Atterberg test?
Liquid Limit
Place a soil paste in the cup.Cut a groove at the center of the soil paste with the standard grooving tool.Lift the cup and drop it from a height of 10mm, using the crank-operated cam. Repeat the procedure at least three times for the same soil at varying moisture contents.
What is Atterberg apparatus?
The Atterberg Limits of soils are determined with a series of laboratory tests that classify the properties of silt and clay soils at different moisture contents. Geotechnical engineers use Atterberg limits to design foundations for structures and predict the behavior of soils for fills, embankments, and pavements.
Why is plastic limit important?
Importance of Plastic Limit Test of Soil
The value of the plastic limit is used to classify the fine-grained soils and evaluating the activities of clayey soil. 2. It indicates the toughness index of soil.
What are limit tests?
Limit testing is a very general term that refers to the testing of any component substance to a defined limit – usually required on a case-by-case basis that are niche to one client. Why do we do it? A limit test may be required with a specific industry regulatory requirement.
Why is liquid limit important?
The liquid limit of a soil is an indicator of the compressibility of a soil. The compressibility of the soil generally increases with an increase in liquid limit. The shrinkage index is directly proportional to the percentage of clay-size fraction present in the soil. It can be used as an indicator of clay.
What is the degree of saturation at shrinkage limit?
A point is eventually reached where this volume change stops, even though the degree of saturation is still essentially 100%. The moisture content at which this occurs is defined as the shrinkage limit (wSL), which, as noted above, is one of the Atterberg limits.
What does high liquid limit mean?
A high liquid limit normally indicates a high compressibility and a high shrinkage/swelling potential. A high-plasticity index Ip generally results in a low shear strength. A low Ip means that a soil used as foundation will change significantly in consistency even with a small change in water content.
