Table of Contents
The liquid limit is the moisture content at which the groove, formed by a standard tool into the sample of soil taken in the standard cup, closes for 10 mm on being given 25 blows in a standard manner. This is the limiting moisture content at which the cohesive soil passes from liquid state to plastic state.
What does liquid limit tell you?
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.
Is liquid limit a percentage?
2.1 The liquid limit of a soil is the moisture content, expressed as a percentage of the weight of the oven-dried soil, at the boundary between the liquid and plastic states of consistency.
Can liquid limit exceed 100?
Atterberg limits cannot exceed 100. d. In AASHTO, A-7-5(30) is a better subgrade material than A-7-5(15). e.
How do you solve liquid limits?
Calculate the liquid limit from only one soil sample test by dividing the number of blows by 25, raising the result to the power of 0.121 and multiplying by the percent water content.
What is the importance of liquid limit?
Value of liquid limit is used to classify fine grained soil. It gives us information regarding the state of consistency of soil on site. Liquid limit of soil can be used to predict the consolidation properties of soil while calculating allowable bearing capacity & settlement of foundation.
Why is liquid limit test important?
If the natural moisture content of soil is higher than liquid limit, the soil can be considered as soft and if the moisture content is lesser than liquid limit, the soil is brittle and stiffer. The value of liquid limit is used in classification of the soil and it gives an idea about plasticity of the soil.
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 are the three 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.
Is high plasticity clay good?
A high PI indicates an excess of clay or colloids in the soil. Its value is zero whenever the PL is greater or equal to the LL. The plasticity index also gives a good indication of compressibility (see Section 10.3). The greater the PI, the greater the soil compressibility.
What is the liquid limit of the soil?
The liquid limit is the moisture content at which the groove, formed by a standard tool into the sample of soil taken in the standard cup, closes for 10 mm on being given 25 blows in a standard manner. At this limit the soil possess low shear strength.
What are the consistency limits of soil?
The three limits are known as the shrinkage limit (WS), plastic limit (WP), and liquid limit (WL) as shown. The values of these limits can be obtained from laboratory tests.
What is plastic limit test?
Plastic limit test is one of the laboratory tests used internationally to differentiate or classify soils into groups. The boundary of soil between the plastic and solid state means, the limit at which the soil starts to behave as a plastic.
What is the shrinkage limit?
The shrinkage limit (SL) is defined as the water content at which the soil changes from a semi-solid to a solid state. At this moisture content the volume of the soil mass ceases to change with further drying of the material. The shrinkage limit is less frequently used than the liquid and plastic limits.
Why do we need Atterberg limits?
The Atterberg limits are a basic measure of the critical water contents of a fine-grained soil: its shrinkage limit, plastic limit, and liquid limit. The Atterberg limits can be used to distinguish between silt and clay, and to distinguish between different types of silts and clays.
What is the importance of Atterberg limits?
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 plastic limit?
Plastic limit is defined as the water moisture content at which a thread of soil with 3.2mm diameter begins to crumble.
How do you find Atterberg limits?
Is determined by subtracting the Plastic limit from the natural water content of the sample, then dividing by the plasticity index. Soils with a LI of 1 or more will be closer to the liquid state. A LI of 0 or lower indicates soils that are harder and more brittle.
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.
What is shrinkage limit test?
A shrinkage limit test gives a quantitative indication of how much moisture can change before any significant volume change and to also indication of change in volume. The shrinkage limit is useful in areas where soils undergo large volume changes when going through wet and dry cycles (e.g. earth dams) APPARATUS. 1.).
What is plasticity of soil?
Plasticity of soil is its ability to undergo deformation without cracking or fracturing. Engineering Properties:- The main engineering properties of soils are permeability, compressibility and shear strength. Permiability indicates facility with which water can flow through soils.
What does vinegar do to clay?
The acidity of the vinegar breaks down the clay a bit, and makes it sticky. Some artists use vinegar straight from the bottle, or add vinegar to clay instead of water to make a joining slip. All these methods work to create a join that is stronger than water or slip alone.
