The liquid limit test, defined in astm standard d4318, determines the water content at which the behavior of a clayey soil changes from plastic to liquid. Turn the crank of the liquid limit at the rate of 2 revolution per second, the sample will rise and drop through a vertical distance of 10mm, the soil from the to sides of the cup begin to flow toward the center, count the number of blow n,to to close the distance of 12. The plasticity index is the size of the range of water contents where the soil exhibits plastic properties. Pdf standard test methods for liquid limit, plastic limit, and. The liquid and plastic limits of soils are often referred the as the atterberg limits. The plastic limit of a soil is the moisture content. The liquid, plastic and shrinkage limits are therefore quantified in terms of the water content at which a soil changes from the liquid to the plastic state. It begins to crumble when rolled into threads of 3mm dia. Determination of plastic limit of soil the constructor. When the plastic limit is equal to or greater than the liquid limit, the plasticity index is reported as zero. The liquid limit ll it is defined as the percentage moisture content at which a soil changes with decreasing wetness from liquid to plastic consistency or with increasing wetness from plastic to liquid consistency. It is strongly recommended that the liquid limit of these soils be determined by the multipoint method. Atterberg limit objective to determine the liquid limit.
Liquid limit is the water content at which soil changes from a plastic to a liquid state, when the soil specimen is just fluid enough for a groove to close when jarred in a specified manner. Liquid limit ll or wl the water content, in percent, of a soil at the arbitrarily defined boundary between the semi liquid and plastic states. In coarse textured soils it is usually difficult to control water content for the liquid limit test and those soils may not even have a plastic limit. Liquid limit, plastic limit, and plasticity index of soils1.
In other words, it is the percentage moisture content at which a soil changes with decreasing wetness from the plastic to the semi solid consistency or with increasing wetness. For determining both plastic and liquid limits, the soil sample must first be sieved through a 0. This test is done to determine the plastic limit of soil as per is. This test is much less commonly used than the liquid and plastic limit tests. Pdf soil liquid limit and plastic limit treating system based on. Three kinds of soil specimens were tested with liquid and plastic limit combined test and the test data was treated with graphic method, excel. California test 226 determination of moisture content by oven drying.
The liquid limit ll or w ll, also known as the upper plastic limit, is the water content at which the soil changes from the liquid state to a plastic state. Plastic limit is the water content at which a soil changes from the plastic state to the semisolid state. Liquid limit, plastic limit, and plasticity index of soils abstract atterberg limits are a basic measure of the critical water contents of a finegrained soil, such as. Atterbergs limits are liquid limit, plastic limit, and plasticity index. Determination of plastic limit is as important as liquid limit so as to ascertain plasticity index, i p of the soil. The liquid limit of soils can be determined by any one of the following two methods. After receiving the soil sample it is dried in air or in oven maintained at a temperature of 60 0 c. Find the relationship between water content and number of blows. However, the transition from plastic to liquid behavior is gradual over a range of water contents, and the shear strength of the soil is not actually zero at the liquid limit. Engineering properties of soils based on laboratory testing. The liquid limit and plastic limit tests are the most commonly used of the atterberg limits tests. Liquid limit ll or is defined as the arbitrary limit of water content at which the soil is just about to pass from the plastic state into the liquid state. If clods are there in soil sample then it is broken with the help of wooden mallet. Chapter 3 standard test procedures classification tests may 2001 page 3.
The difference between the liquid limit and plastic limit is the plasticity index. The liquid limit, plastic limit, and plasticity index of soils are also used extensively, either individually or together. May 14, 20 for determination of the plastic limit of soil. Mar 07, 2015 liquid limit is defined as the minimum water content at which a pat of soil cut by a groove of standard dimension will flow together for a distance of 12 mm 12 inch under an impact of 25 blows in the device. The value of liquid limit helps in classification of fine grain soil. The plastic limit pl is determined by rolling out a thread of the fine portion of a soil on a flat, nonporous surface. Determination of plastic limit, liquid limit and plasticity index a. Atterberg limits soil classification liquid limit, plastic. As the moisture content of a soil decreases the soil passes from the liquid state to the plastic state to the solid state. Atterberg limits test equipment, astm d4318 gilson co. Sep 05, 20 determination of liquid limit and plastic limit of soil. In 1911, the swedish agriculturist atterberg divided the entire range of soil state from liquid to solid state into four stages, which is known as atterberg. Gilson carries all the equipment needed to perform liquid limit, plastic limit, and shrinkage limit tests in accordance with astm d4318 and astm d4943 standards, and other associated test methods. Place a portion of the prepared sample in the cup of the liquid limit device at the point where the cup rests on the base and spread it so that it is 10mm deep at its deepest point.
Ruwan rajapakse pe, ccm, cce, avs, in geotechnical engineering calculations and rules of thumb second edition, 2016. A soil with high clay content usually has high liquid and plastic limits and a less cohesive soil gives low figures. Liquid limit is significant to know the stress history and general properties of the soil met with. Liquid limit of soil is a very important property of fine grained soil or cohesive soil. The plastic limit expressed as the water content in percentage of the weight of the oven dry soil using weights as obtained in section 3 c shall be calculated in accordance with section 4. Liquid limit ll is defined as a limiting water content separating the viscous liquid state and plastic state of soil consistency. It is the water content at which a soil changes from plastic to liquid behavior. The tensions of the water at the lower plastic limit and upper plastic limit are equivalent to. The liquid limit astm d4318 is defined as the water content at which the behavior of a clayey soil changes from plastic to liquid. Liquid limit ll or wl the water content, in percent, of a soil at the arbitrarily defined boundary between the semiliquid and plastic states.
Aug 06, 2017 appendix i3 is the laboratory form of liquid limit, plastic limit and plasticity index determinations. Appendix i3 is the laboratory form of liquid limit, plastic limit and plasticity index determinations. Or it is the minimum moisture content at which a soil flows upon application of very small shear force. Ppt atterberg limits of soil powerpoint presentation. Take care to eliminate air bubbles from the soil specimen. Atterberg limits, liquid limit, plastic limit of soil. Infiltration, permeability, liquid limit and plastic limit of. Atterberg limits testing is a group of tests used to define the properties of cohesive soils at different moisture contents. This test method covers the determination of the liquid limit, plastic limit and plasticity index of soils. May 07, 2017 plastic limit test is one of the laboratory tests used internationally to differentiate or classify soils into groups. What is the plastic limit and liquid limit of soil. They are as follows, solid semi solid liquid plastic nearly sixty years ago a chemist known as a. This test method describes the procedures for determining the liquid limit, plastic limit, and plasticity index of a soil including cement or lime treated soils.
From liquid limit test, the compression index may be estimated, which is used in settlement analysis. The pi is the difference between the liquid limit and the plastic limit pi llpl. The moisture content corresponding to n 25, determined from the curve, is the liquid limit of the soil. 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. In 1911, the swedish agriculturist atterberg divided the entire range of soil state from liquid to solid state into four stages, which is known as atterberg limits or consistency limits. Plastic limit test of soilis2720part51985 civilblog. Limitations of liquid limit test procedure for determination of the plastic limit. It flows to close the groove in just 25 blows in casagrandes liquid limit device.
In the upper plastic limit the film of oriented water molecules becomes so thick that cohesion is decreased and the entire soil water mass flows freely under an applied force. Determination of liquid and plastic limit second revision. The liquid limit of a soil is the water content at which the soil behaves practically like a liquid, but has small shear strength. Definition the liquid limit ll of a soil is the water content at which the soil passes from a plastic state to a liquid state. It is the minimum moisture content at which a soil flows upon application of very small shear force. The group performed standard practice in determining the liquid limit, plastic limit, and plasticity index of a soil sample in accordance to astm d 4318. 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.
The plastic limit of finegrained soil is the water content of the soil below which it ceases to be plastic. The plastic limit of a soil is the moisture content, expressed as a percentage of the weight of the ovendry soil, at the boundary between the plastic and semisolid states of consistency. Apr 07, 20 liquid limit of soil, determination of liquid limit plastic limit, atterberg limit test procedure,ll duration. Because the liquid limit and plastic limit are the two most commonly used atterberg limits, the following. Significance of consistency tests if the timeconsuming hydrometer test is not performed on the fine fractions of a soil, reliance is placed upon the limit tests to tell whether the materials passing the 0. These limits distinguished the boundaries of the several consistency states of plastic soils. There soil can be classified into four states depending on the water content of soil. Liquid limit of soil, determination of liquid limit plastic limit, atterberg limit test procedure,ll duration. Article pdf available in geotechnical testing journal 331.
In other words, the liquid limit is the minimum moisture. About 120 gm of airdried soil from thoroughly mixed portion of material passing 425 micron i. As it is difficult to get exactly 25 blows in a test, 3 to 4 tests are conducted and the number of blows n required in each test. The plastic limit test is performed by repeated rolling of an. The range of moisture contents over which the soil is plastic is used as a measure of the. The liquid limit, also known as the upper plastic limit, is the water content at which soil changes from the liquid state to a plastic state. Determine the plastic limit of soil civil engineering. The tensions of the water at the lower plastic limit and upper plastic limit are equivalent to pf values 2.
This test attempts to deform a soil specimen below the moisture by. When determining the plastic limit, two procedures for rolling portions of the test specimen are provided as follows. Permeability test of soil by falling, constant head permeameter. Determination of liquid limit and plastic limit of soil youtube. Standard test methods for liquid limit, plastic limit, and. The plastic limit pl or w pl, also known as the lower plastic limit, is the water content at which a soil changes from the plastic state to a semisolid state. This also applies if the plastic limit is equal to or greater than the liquid limit. Aashto t 87 dry preparation of disturbed soil and soil aggregate samples for test. Add sufficient water to produce a consistency that will require 25 to 35 drops of the cup to cause closure.
Pdf determination of plastic and liquid limits using the reverse. The values for these limits are dependent on various soil parameters. The liquid and plastic limit tests attempt to fix the moisture contents at which a clay soil passes from the solid to the plastic state and from the plastic to the liquid state. With your download, get the 18 best papers relevant to this one, including 14 top related papers. The method described herein is based upon aashto designation t89 which has been modified for new york state department of transportation use. If it is possible to perform the plastic limit test, the soil is reported as non plastic np. Determination of plastic limit is as important as liquid limit so as to ascertain plasticity index, ip of the soil. Astm d 4318 standard test method for liquid limit, plastic limit, and. Liquid limit is defined as the minimum water content at which a pat of soil cut by a groove of standard dimension will flow together for a distance of 12 mm 12 inch under an impact of 25 blows in the device. Plastic limit test, procedures, sample calculations basic. The calculated liquid limit of the soil sample is 34, its plastic limit as 20, and plasticity index as 14. Atterberg defined three boundary levels between these four states.
Pdf standard test methods for liquid limit, plastic. The atterberg limits are empirical tests which are used to indicate the plasticity of fine grained soil by the differentiation between highly plastic, moderately plastic and non plastic soils. The value is also reported to the nearest whole number. Atterberg limit test soil mechanics basic civil engineering. Determine liquid limit of soil specimen by casagrande method.
Liquid limit, plastic limit, and plasticity index of soils abstract atterberg limits are a basic measure of the critical water contents of a finegrained soil, such as its shrinkage limit, plastic limit, and liquid limit. Plastic limit is the water content at the change from a plastic to a semisolid state. In this article test methods used for determination of soil plastic limit in accordance with astm d4148 will be presented. Determination of liquid limit and plastic limit of soil. They are, shrinkage limit liquid limit plastic limit. After we have done the experiment liquid limit and plastic limit tests, we found that the plastic index of the soil is equal to 27 and the liquid limit of the soil is equal to 50. If no method is specified, use the wet preparation method. The test to determine the shrinkage limit is astm international d4943. Humboldt offers the h4254 shrinkage limit set for performing this test.
If it is possible to perform the plastic limit test, the soil is reported as nonplastic np. Note 1 allow ample time for mixing and curing since variations can cause erroneous test results. The plastic limit pl is the water content, in percent, at which a soil can no longer be deformed by rolling into 3. However, the transition from plastic to liquid behavior is gradual over a range of water contents, and the shear. Plastic limit test is one of the laboratory tests used internationally to differentiate or classify soils into groups. Liquid limit is defined as the water content at which the soil changes from liquid state to plastic state. At this water content plastic limit, the soil will crumble when rolled into threads of 3. Plastic limit test, procedures, sample calculations. Jul 04, 2015 the amount of water in the soil determines the type of soil. Liquid limit and plastic limit tests lab experiments. The plastic limit of a soil is the moisture content at which soil begins to behave as a plastic material. At this limit, the soil possesses a small value of shear strength, losing its ability to flow as a liquid.
526 326 54 707 518 1210 1211 415 581 338 1396 1245 506 1335 1339 1290 125 1156 248 1230 806 831 839 67 1293 80 196 802 887 1503 667 443 252 1514 259 857 285 705 922 214 347 849 690 1409 858 1398 172 362 225