Table of Contents
What is the Atterberg Limits Test? Atterberg limits tests establish the moisture contents at which fine-grained clay and silt soils transition between solid, semi-solid, plastic, and liquid states.
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 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 difference between liquid limit and plastic limit called?
The difference between the liquid limit and the plastic limit is known as the plasticity index (IP), and it is in this range of water content that the soil has a plastic consistency. The consistency of most soils in the field will be plastic or semi-solid.
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).
How do you find Preconsolidation stress?
Draw the bisector line between the previous horizontal and tangent lines, and draw the NCL; The vertical stress corresponding to the point of intersection between the bisector line and the NCL represents the preconsolidation pressure, .
What is the limit test?
Limit test is defined as quantitative or semi quantitative test designed to identify and control small quantities of impurity which is likely to be present in the substance. Limit test is generally carried out to determine the inorganic impurities present in compound.
What does the plastic limit tell you?
Plastic Limit (PL) is the water content at the change from a plastic to a semi-solid state. Shrinkage Limit (SL) is the water content where the further loss of moisture does not cause a decrease in specimen volume.
How do you calculate liquidity index?
Use the following steps to calculate the liquidity index: Multiply the ending trade receivables balance by the average collection period. Multiply the ending inventory balance by the average inventory liquidation period. Summarize the first two items and divide by the total of all trade receivables and inventory.
Is code for Atterberg limits?
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 does a low plastic limit mean?
The Plastic Limit, also known as the lower plastic limit, is the water content at which a soil changes from the plastic state to a semisolid state. OR. The soil moisture content at which any increase in the moisture content will cause a semi-solid soil to become plastic.
Is plasticity a chart?
A plasticity chart , based on the values of liquid limit (WL) and plasticity index (IP), is provided in ISSCS to aid classification. The ‘A’ line in this chart is expressed as IP = 0.73 (WL – 20). Depending on the point in the chart, fine soils are divided into clays (C), silts (M), or organic soils (O).
How do you find the liquid limit?
The tester places soil samples with varying water contents into the cup of the device, then cuts a groove through the sample. The cup is dropped multiple times until soil fills the groove. Use the number of drops along with the water content of the samples to calculate the liquid limit.
Can liquid limit be more than 100%?
For Attapulgite, the liquid limit varies from 150 to 250, which are greater than 100 and the shrinkage limit varies from 100 to 125 which are also greater than 100. Therefore, the Atterberg’s limits can be greater than 100.
What is specific gravity of soil?
Specific Gravity(G) Specific gravity is defined as the ratio of the weight of a given volume of soil solids at a given temperature to the weight of an equal volume of distilled water at that temperature, both weights being taken in air.. The specific gravity of the soil particles lie with in the range of 2.65 to 2.85.
What is the use of Casagrande apparatus?
Used to determine the moisture content at which clay soils pass from a plastic to a liquid state. Comprises: removable brass cup, adjustable crank and cam mechanism, blow counter, and base. Different versions are available conforming to the various Standards in use.
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.
How is plastic limit calculated?
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 is Atterberg apparatus?
Atterberg limit test equipment from Gilson meets ASTM D4318, ASTM D4943, and other standard test methods. Atterberg Limits/Grain Size Accessories include spatulas, wash bottles, mortar & pestles, evaporating dishes, sample containers, and graduated cylinders used for Atterberg limits and grain size testing.
What is Casagrande method?
A method for determining the liquid limit of a soil. A paste of soil and water is put in a shallow cup, the paste is cut into two parts with a deep groove and the cup is then dropped repeatedly in a standard manner until the groove has closed owing to the flow of the paste.
What is a toughness index?
Toughness index is defined as the ratio of plasticity index (IP) of the soil to the flow index (IF) of the soil. Toughness index varies between 0 to 3. This gives us an idea of shear strength of soil at its plastic limit.
