The plastic limit signifies the percentage of moisture at which the soil changes, with decreasing wetness, from a plastic to a semisolid state, or with increasing wetness, from the semisolid to the plastic state. In this article test methods used for determination of soil plastic limit in accordance with astm d4148 will be presented. Astm 2009 standard test methods for particlesize distribution gradation of soils using sieve analysis. The plastic limit is one of the measured parameters of the atterberg limits test astm, 2010. Liquid limit ll is defined as a limiting water content separating the viscous liquid state and plastic state of soil consistency. The water content at which soil sample change from plastic state to semisolid state. Learn more about the elastic limit in this article. 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.
When stresses up to the elastic limit are removed, the material resumes its original size and shape. It is the moisture content at which a thread of soil can be. Plastic limit of soil the plastic limit signifies the percentage of moisture at which the soil changes, with decreasing wetness, from a plastic to a semisolid state, or with increasing wetness, from the semisolid to the plastic state. The plastic limit, given by the rolling test, has a long.
These limits are expressed as percent water content. Williams, in gold ore processing second edition, 2016. In each state, the consistency and behavior of a soil is different and consequently so are its engineering properties. Elastic limit, maximum stress or force per unit area within a solid material that can arise before the onset of permanent deformation. Definition liquid limit is defined as the water content at which the soil changes from liquid state to plastic state. The value of the atterberg limits of a cohesive soil.
Atterberg limits testing is widely used in the design stage of construction to ensure that the. The plastic limit analysis of a statically indeterminate reinforced concrete. Liquid limit is defined as the minimum water content at percent on dry bases at which the soil changes its state from liquid to plastic state. The swedish soil scientist albert atterberg originally defined seven limits of consistency to classify finegrained soils, but in current engineering. The atterberg limits which are most useful for engineering purposes are the liquid limit, plastic limit, and shrinkage limit. This method covers the determination of the plastic limit of a soil as defined hereunder by measuring the lowest moisture content at which the soil can be rolled.
The following moisture conditions liquid limit, plastic limit, along with shrinkage limit are referred to as the atterberg limits, after the originator of the test procedures. The plastic limit of a soil is the moisture content at which soil begins to behave as a plastic material. At this water content plastic limit, the soil will crumble when rolled into threads of 3. In current engineering usage, the term usually refers only to the liquid limit, plastic limit, and in some references, the shrinkage limit. Soil consistency is defined as the relative ease with which a soil can.
Atterberg limit definition is a measure of a soil samples capacity for containing water used to determine the soils structural characteristics usually plural. Plastic limit is defined as the minimum water content at percent on dry bases at which a soil enters from semisolid state to plastic state. They have been used in soil mechanics for over 50 years, providing a measure of the moisture content at which a soil tailings changes from a liquid, to a plastic, to a. What is the plastic limit and liquid limit of soil. Shrinkage limit is defined as, the maximum water content at which a reduction in water content will not cause a. Plastic limit is defined as the water moisture content at which a thread of soil with. The determination of the plastic limit and plasticity index of soils. The soil moisture content at which any increase in the moisture content will cause a. The liquid and plastic limits of a soil define the range within which a cohesive soil behaves in a plastic state. Plastic limit and other consistency parameters by a bending method and interpretation of plasticity classification in soils. Standard test methods for liquid limit, plastic limit, and. Liquid limit ll or wl the water content, in percent, of a soil at the arbitrarily defined boundary between the semiliquid and plastic states. Ruwan rajapakse pe, ccm, cce, avs, in geotechnical engineering calculations and rules of thumb second edition, 2016.
The atterberg limits liquid limit, plastic limit, and shrinkage limit provide a very useful indication of the properties of the tailings. The atterberg limits are a basic measure of the critical water contents of a finegrained soil. Atterberg, a wellknown scientist, suggested three values namely upper plastic limit, lower plastic limit and plasticity. Atterberg limits are used extensively by soil scientists. Atterberg limit definition of atterberg limit by merriam. Atterberg, a wellknown scientist, suggested three values namely upper plastic limit, lower plastic limit and plasticity number or plasticity index and so they are called atterberg limits.
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