What is the purpose of the Atterberg limit test?

The limits relate the determined moisture contents to empirically defined boundaries between states of consistency (liquid, plastic and solid) (Baver et al., 1972). The aim of the Atterberg limit tests is to obtain empirical information on the reaction of regolith to water.

What is the procedure for determining the plastic limit?

Calculate the plastic limit wp by dividing the “weight of moisture” by the “dry weight of sample” and multiply by 100. Plasticity Index (Ip) of a soil is the numerical difference between its Liquid Limit and its Plastic Limit.

What do Atterberg Limits tell us?

In the field, the Atterberg Limits, can be used as a guide indicating how much a soil is likely to settle or consolidate under load. If the field moisture is near the liquid limit, a lot of settlement is likely. The opposite is true if the field moisture is near or below the plastic limit.

Is code for Atterberg limit test?

STANDARD • IS: 2720 (Part 5) 1985. DEFINITION • Liquid Limit is defined as the water content at which the soil changes from liquid state to plastic state. APPARATUS • Casagrande apparatus confirming to IS: 9259-1979. Grooving tool.

What are the three 3 Atterberg limits?

7.3. 3 Atterberg Limits. 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 plastic limit test is done?

Plastic limit test is one of the laboratory tests used internationally to differentiate or classify soils into groups. When the water content or moisture content of soil increases beyond a limit then the soil starts to behave as liquid.

What is the plastic limit?

DEFINITION. 2.1 The plastic limit of a soil is the moisture content, expressed as a percentage of the weight of the oven-dry soil, at the boundary between the plastic and semisolid states of consistency. It is the moisture content at which a soil will just begin to crumble when rolled into a thread ⅛ in.

What are the significance of consistency limits?

A gradual increase in water content causes the soil to change from solid to semi-solid to plastic to liquid states. The water contents at which the consistency changes from one state to the other are called consistency limits (or Atterberg limits).

What is a good plasticity index?

Some critical values of the plasticity index for aquaculture To construct a pond dike without a clay core*, the plasticity index of the soil material should have a value between 8 and 20 percent. For best compaction, the PI should be as close to 16 percent as possible (see Section 10.3).

What is the importance of plastic limit?

Plastic Limit: The plastic limit is the minimum moisture content at which the soil can be deformed plastically. As standardized, it can be taken as the smallest water content at which the soil begins to crumble when rolled out into thin threads, approximately 3mm in diameter.

Why plastic limit test is 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. It gives an idea regarding the consistency of soil.

What is the liquid limit of the Atterberg test?

Shrinkage Limit. The liquid limit is one of the atterberg limits and this test determines the water content at which the behavior of clayey soil changes from plastic to liquid OR It is the minimum moisture content at which a soil flows upon application of very small shear force and this limit is also known as an upper plastic limit.

What is the standard operating procedure for Atterberg limits?

This Standard Operating Procedure (SOP) provides technical guidance and procedures that will be employed for Atterberg limits tests. It addresses equipment, procedures, and personnel responsibilities. Atterberg limits tests consist of two tests called Plastic Limit, PL, and Liquid Limit, LL.

How to report the results of the Atterberg test?

Your report should include the following: Analysis of test results – Complete the table provided and show one sample calculation. Calculate the value for liquid limit, flow index, plastic limit, plasticity index and shrinkage limit. Summary and conclusions – Comment on the Atterberg limit values of the given soil sample.

How is the Atterberg limit used in soil classification?

The Atterberg limit refers to the liquid limit and plastic limit of soil. These two limits are used internationally for soil identification, classification, and strength correlations. When clay minerals are present in fine-grained soil, the soil can be remolded in the presence of some moisture without crumbling.