Table of Contents
The plastic limit (PL) is the water content, in percent, at which a soil can no longer be deformed by rolling into 3.2 mm (1/8 in.) Those limit of soil are very important property of fine grained soil and its Value is used to classify fine grained soil and calculate activity of clays and toughness index of soil.
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.
What is significance 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.
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 the liquid limit of soil?
Liquid limit is the water content where the soil starts to behave as a liquid. Liquid limit is measured by placing a clay sample in a standard cup and making a separation (groove) using a spatula. The cup is dropped till the separation vanishes. The water content of the soil is obtained from this sample.
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 high plastic limit?
The plastic limit (PL) is the water content, in percent, at which a soil can no longer be deformed by rolling into 3.2 mm (1/8 in.) Those limit of soil are very important property of fine grained soil and its Value is used to classify fine grained soil and calculate activity of clays and toughness index of soil.
What is the plastic limit of soil?
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?
Consistency limits are very significant in the study of clays and other fine-grained soils. Important deductions can be made based on the relative values of consistency limits and the index properties as follows: 1. The liquid limit and plasticity index are extremely useful for the classification of soils.
What is plastic limit in elasticity?
Elastic limit is defined as the maximum stress that a material can withstand before the permanent deformation. It is the highest limit of the material before the plastic deformation of the material can occur. Once the stress or force is removed from the material, the material comes back to its original shape.
How can you tell if plastic is clay?
As with other types of materials, a compression test can be used to evaluate the plasticity of clays. Baran et al. formulated their workability concept for clays using compression tests in cylindrical samples, allowing to determine the optimum amount of moisture for each clay studied.
Is plastic limit a percentage?
The plastic limit (PL) The percentage moisture content at which a soil changes with decreasing wetness from the plastic to the semi- solid consistency or with increasing wetness from the semi-solid to the plastic consistency. A small increase in moisture above the plastic limit will destroy the cohesion* of the soil.
Why is there 25 blows in liquid limit?
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 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.
What is the plastic limit?
The plastic limit is the water content at which a soil-water paste changes from a semisolid to a plastic consistency as it is rolled into a 3.175-mm (1/8-inch) diameter thread in a standard test.
What is the practical significance of determining plastic limit of the soil?
Significance and Use The liquid limit, plastic limit and plasticity index of soils are also used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, permeability, compactibility, shrink‑swell and shear strength.
At what diameter will a soil thread starts to crumble when it reaches the plastic limit?
The plastic limit is when a thread of soil rolled out on a nonporous surface begins to crumble when it reaches 1/8 in in diameter.
What is the importance of liquid limit and plastic limit in soil classification?
Those limit of soil are very important property of fine grained soil and its Value is used to classify fine grained soil and calculate activity of clays and toughness index of soil. Moreover, it also gives us information regarding the state of consistency of soil on site.
What is plastic soil?
“Plastic soil” generally means the soil is predominantly clay – and the more plastic the soil, the more expansive it will likely be. The soil’s plasticity is measured by two tests: the Plastic limit and the Liquid limit.
What are the various consistency limits?
2. Historical background Swedish agriculture engineer ATTERBERG was the one who mentioned that a fine grained soil can exist in four states: liquid plastic semi-solid solid So consistency limits are also known Atterberg’s limits. 4.
What does plasticity index indicate?
The difference between liquid and plastic limits is called the plasticity index, and it represents the range of water content over which the soil is plastic. The plasticity index, in combination with water content at liquid limit (wL), indicates how sensitive the soil is to the changes in moisture content.
What is Atterberg limit test?
Atterberg limits is a basic measure of the critical water content of fine-grained soils. These tests include shrinkage limit, plastic limit, and liquid limit, which are outlined in ASTM D4318. Depending on the water content of a soil, it may appear in four states: solid, semi-solid, plastic and liquid.
