1、Designation: D4318 10Standard Test Methods forLiquid Limit, Plastic Limit, and Plasticity Index of Soils1This standard is issued under the fixed designation D4318; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the determination
3、of the liquidlimit, plastic limit, and the plasticity index of soils as definedin Section 3 on Terminology.1.2 Two methods for preparing test specimens are providedas follows: Wet preparation method, as described in 10.1. Drypreparation method, as described in 10.2. The method to beused shall be spe
4、cified by the requesting authority. If nomethod is specified, use the wet preparation method.1.2.1 The liquid and plastic limits of many soils that havebeen allowed to dry before testing may be considerablydifferent from values obtained on non-dried samples. If theliquid and plastic limits of soils
5、are used to correlate orestimate the engineering behavior of soils in their natural moiststate, samples should not be permitted to dry before testingunless data on dried samples are specifically desired.1.3 Two methods for determining the liquid limit are pro-vided as follows: Method A, Multipoint t
6、est as described inSections 11 and 12. Method B, One-point test as described inSections 13 and 14. The method to be used shall be specifiedby the requesting authority. If no method is specified, useMethod A.1.3.1 The multipoint liquid limit method is generally moreprecise than the one-point method.
7、It is recommended that themultipoint method be used in cases where test results may besubject to dispute, or where greater precision is required.1.3.2 Because the one-point method requires the operator tojudge when the test specimen is approximately at its liquidlimit, it is particularly not recomme
8、nded for use by inexperi-enced operators.1.3.3 The correlation on which the calculations of theone-point method are based may not be valid for certain soils,such as organic soils or soils from a marine environment. It isstrongly recommended that the liquid limit of these soils bedetermined by the mu
9、ltipoint method.1.4 The plastic limit test is performed on material preparedfor the liquid limit test.1.5 The liquid limit and plastic limit of soils (along with theshrinkage limit) are often collectively referred to as theAtterberg limits. These limits distinguished the boundaries ofthe several con
10、sistency states of plastic soils.1.6 The composition and concentration of soluble salts in asoil affect the values of the liquid and plastic limits as well asthe water content values of soils (see Method D4542). Specialconsideration should therefore be given to soils from a marineenvironment or othe
11、r sources where high soluble salt concen-trations may be present. The degree to which the salts presentin these soils are diluted or concentrated must be given carefulconsideration.1.7 The methods described herein are performed only onthat portion of a soil that passes the 425-m (No. 40) sieve.There
12、fore, the relative contribution of this portion of the soil tothe properties of the sample as a whole must be consideredwhen using these tests to evaluate properties of a soil.1.8 The values stated in SI units are to be regarded as thestandard, except as noted below. The values given in parenthe-ses
13、 are for information only.1.8.1 The standard units for the resilience tester covered inAnnex A1 are inch-pound, not SI. The SI values given are forinformation only.1.9 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1
14、.9.1 For purposes of comparing a measured or calculatedvalue(s) with specified limits, the measured or calculatedvalue(s) shall be rounded to the nearest decimal or significantdigits in the specified limits1.9.2 The procedures used to specify how data are collected/recorded or calculated, in this st
15、andard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures do not consider material variation, purpose for obtainingthe data, special purpose studies, or any considerations for the1This standard is und
16、er the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.03 on Texture, Plasticityand Density Characteristics of Soils.Current edition approved Jan. 15, 2010. Published March 2010. Originallyapproved in 1983. Last previous edition approved in 200
17、5 as D4318 05. DOI:10.1520/D4318-10.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.users objectives; and it is common practice to increase orreduce significant digits
18、 of reported data to be commensuratewith these considerations. It is beyond the scope of thisstandard to consider significant digits used in analysis methodsfor engineering design.1.10 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresp
19、onsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C702 Practice for Reducing Samples of Aggregate to Test-ing SizeD75 Practice for Sampling A
20、ggregatesD420 Guide to Site Characterization for Engineering De-sign and Construction PurposesD653 Terminology Relating to Soil, Rock, and ContainedFluidsD1241 Specification for Materials for Soil-Aggregate Sub-base, Base, and Surface CoursesD2216 Test Methods for Laboratory Determination of Wa-ter
21、(Moisture) Content of Soil and Rock by MassD2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System)D3282 Practice for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction PurposesD3740 Practice for Minimum Requirements for Agenci
22、esEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4542 Test Method for Pore Water Extraction and Deter-mination of the Soluble Salt Content of Soils by Refrac-tometerD4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses
23、for Use in Soil, Rock, andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaborat
24、ory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 For common definitions of terms in this standard, referto Terminology D653.3.1.2 Atterberg LimitsOriginally, six “limits of consis-tency” of fine-grained soils were defined by Albert Atterberg:the upper limit of
25、viscous flow, the liquid limit, the sticky limit,the cohesion limit, the plastic limit, and the shrinkage limit. Incurrent engineering usage, the term usually refers only to theliquid limit, plastic limit, and in some references, the shrinkagelimit.3.1.3 consistencythe relative ease with which a soi
26、l can bedeformed.3.1.4 liquid limit (LL, wL)the water content, in percent, ofa soil at the arbitrarily defined boundary between the semi-liquid and plastic states.3.1.4.1 DiscussionThe undrained shear strength of soil atthe liquid limit is considered to be approximately 2 kPa (0.28psi).3.1.5 plastic
27、 limit (PL, wp)the water content, in percent,of a soil at the boundary between the plastic and semi-solidstates.3.1.6 plastic soila soil which has a range of water contentover which it exhibits plasticity and which will retain its shapeon drying.3.1.7 plasticity index (PI)the range of water content
28、overwhich a soil behaves plastically. Numerically, it is the differ-ence between the liquid limit and the plastic limit.3.1.8 liquidity indexthe ratio, expressed as a percentage of(1) the water content of a soil minus its plastic limit, to (2) itsplasticity index.3.1.9 activity number (A)the ratio o
29、f (1) the plasticityindex of a soil to (2) the percent by mass of particles having anequivalent diameter smaller than 2 m.4. Summary of Test Method4.1 The specimen is processed to remove any materialretained on a 425-m (No. 40) sieve. The liquid limit isdetermined by performing trials in which a por
30、tion of thespecimen is spread in a brass cup, divided in two by a groovingtool, and then allowed to flow together from the shocks causedby repeatedly dropping the cup in a standard mechanicaldevice. The multipoint liquid limit, MethodA, requires three ormore trials over a range of water contents to
31、be performed andthe data from the trials plotted or calculated to make arelationship from which the liquid limit is determined. Theone-point liquid limit, Method B, uses the data from two trialsat one water content multiplied by a correction factor todetermine the liquid limit.4.2 The plastic limit
32、is determined by alternately pressingtogether and rolling into a 3.2-mm (18-in.) diameter thread asmall portion of plastic soil until its water content is reduced toa point at which the thread crumbles and can no longer bepressed together and re-rolled. The water content of the soil atthis point is
33、reported as the plastic limit.4.3 The plasticity index is calculated as the differencebetween the liquid limit and the plastic limit.5. Significance and Use5.1 These test methods are used as an integral part of severalengineering classification systems to characterize the fine-grained fractions of s
34、oils (see Practices D2487 and D3282) andto specify the fine-grained fraction of construction materials(see Specification D1241). The liquid limit, plastic limit, andplasticity index of soils are also used extensively, eitherindividually or together, with other soil properties to correlate2For refere
35、nced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.D4318 102with engineering behavior such as compressibility, hydrauliccon
36、ductivity (permeability), compactibility, shrink-swell, andshear strength.5.2 The liquid and plastic limits of a soil and its watercontent can be used to express its relative consistency orliquidity index. In addition, the plasticity index and thepercentage finer than 2-m particle size can be used t
37、odetermine its activity number.5.3 These methods are sometimes used to evaluate theweathering characteristics of clay-shale materials. When sub-jected to repeated wetting and drying cycles, the liquid limitsof these materials tend to increase. The amount of increase isconsidered to be a measure of a
38、 shales susceptibility toweathering.5.4 The liquid limit of a soil containing substantial amountsof organic matter decreases dramatically when the soil isoven-dried before testing. Comparison of the liquid limit of asample before and after oven-drying can therefore be used as aqualitative measure of
39、 organic matter content of a soil (seePractice D2487.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740, generally, are consid
40、ered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Ap
41、paratus6.1 Liquid Limit DeviceA mechanical device consistingof a brass cup suspended from a carriage designed to control itsdrop onto the surface of a block of resilient material that servesas the base of the device. Fig. 1 shows the essential featuresand critical dimensions of the device. The devic
42、e may beoperated by either a hand crank or electric motor.6.1.1 BaseA block of material having a resilience re-bound of at least 77 % but no more than 90 %. Conductresilience tests on the finished base with the feet attached.Details for measuring the resilience of the base are given inAnnex A1.6.1.2
43、 Rubber Feet, supporting the base, designed to providedynamic isolation of the base from the work surface.6.1.3 Cup, brass, with a mass, including cup hanger, of 185to 215 g.6.1.4 CamDesigned to raise the cup smoothly and con-tinuously to its maximum height, over a distance of at least180 of cam rot
44、ation, without developing an upward ordownward velocity of the cup when the cam follower leavesthe cam. (The preferred cam motion is a uniformly acceleratedlift curve.)NOTE 2The cam and follower design in Fig. 1 is for uniformlyaccelerated (parabolic) motion after contact and assures that the cup ha
45、sno velocity at drop off. Other cam designs also provide this feature andmay be used. However, if the cam-follower lift pattern is not known, zerovelocity at drop off can be assured by carefully filing or machining thecam and follower so that the cup height remains constant over the last 20to 45 of
46、cam rotation.6.1.5 Carriage, constructed in a way that allows convenientbut secure adjustment of the height-of-drop of the cup to 10mm (0.394 in.), and designed such that the cup and cup hangerassembly is only attached to the carriage by means of aFIG. 1 Hand-Operated Liquid Limit DeviceD4318 103rem
47、ovable pin. See Fig. 2 for definition and determination ofthe height-of-drop of the cup.6.1.6 Motor Drive (Optional)As an alternative to thehand crank shown in Fig. 1, the device may be equipped witha motor to turn the cam. Such a motor must turn the cam at2 6 0.1 revolutions per second and must be
48、isolated from therest of the device by rubber mounts or in some other way thatprevents vibration from the motor being transmitted to the restof the apparatus. It must be equipped with an ON-OFF switchand a means of conveniently positioning the cam for height-of-drop adjustments. The results obtained
49、 using a motor-drivendevice must not differ from those obtained using a manuallyoperated device.6.2 Flat Grooving ToolA tool made of plastic ornoncorroding-metal having the dimensions shown in Fig. 3.The design of the tool may vary as long as the essentialdimensions are maintained. The tool may, but need not,incorporate the gauge for adjusting the height-of-drop of theliquid limit device.NOTE 3Prior to the adoption of this test method, a curved groovingtool was specified as part of the apparatus for performing the liquid limittest. The curved tool is not
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