1、Designation: D4318 171Standard 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 r
2、evision. 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 U.S. Department of Defense.1NOTEEditorially updated units of measurement stat
3、ement in April 2018.1. Scope*1.1 These test methods cover the determination of the liquidlimit, plastic limit, and the plasticity index of soils as definedin Section 3 on Terminology.1.2 Two procedures for preparing test specimens are pro-vided as follows: Specimen Preparation Procedure 1 (WetPrepar
4、ation), as described in 11.1 and Specimen PreparationProcedure 2 (Dry Preparation), as described in 11.2. Thespecimen preparation procedure to be used shall be specifiedby the requesting authority. If no specimen preparation proce-dure is specified, use the wet preparation procedure. (SeeSection 6,
5、Interferences.)1.3 Two methods for determining the liquid limit are pro-vided as follows: Liquid Limit Method A (Multipoint Method),as described in Sections 12 and 13, and Liquid Limit Method B(One-Point Method), as described in Sections 14 and 15. Themethod to be used shall be specified by the requ
6、estingauthority. If no method is specified, use Method A. (SeeSection 6, Interferences.)1.4 The plastic limit test, Method for Plastic Limit,isperformed on material prepared for the liquid limit test. Whendetermining the plastic limit, two procedures for rolling por-tions of the test specimen are pr
7、ovided as follows: Plastic LimitRolling Procedure 1 (Hand Rolling), and Plastic Limit RollingProcedure 2 (Using the Rolling Device).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 th
8、e boundaries ofthe several consistency states of plastic soils.1.6 The plasticity index, Method for Plasticity Index,iscalculated using results from liquid limit and plastic limittesting.1.7 The methods described herein are performed only onthat portion of a soil that passes the 425-m (No. 40) sieve
9、.Therefore, the relative contribution of this portion of the soil tothe properties of the sample as a whole must be consideredwhen using these methods to evaluate the properties of a soil.1.8 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units
10、areprovided for information only and are not considered standard.1.8.1 The converted inch-pound units use the gravitationalsystem of units. In this system, the pound (lbf) represents a unitof force (weight), while the unit for mass is slugs. Theconverted slug unit is not given, unless dynamic (F = m
11、a)calculations are involved.1.8.2 It is common practice in the engineering/constructionprofession to concurrently use pounds to represent both a unitof mass (lbm) and of force (lbf). This implicitly combines twoseparate systems of units; that is, the absolute system and thegravitational system. It i
12、s scientifically undesirable to combinethe use of two separate sets of inch-pound units within a singlestandard. As stated, this standard includes the gravitationalsystem of inch-pound units and does not use/present the slugunit for mass. However, the use of balances or scales recordingpounds of mas
13、s (lbm) or recording density in lbm/ft3shall notbe regarded as nonconformance with this standard.1.8.3 The “alternative” sieve size designations listed inSpecification E11 for the 425-m and 2.00-mm sieves aregiven in parentheses following the “standard” designations,that is, 425-m (No. 40) and 2.00-
14、mm (No. 10).1.8.4 The standard units for the resilience tester covered inAnnex A1 are inch-pound, not SI. The SI values given in Fig.A1.1 are for information only.1.9 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.
15、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 limits.1.9.2 The procedures used to specify how data are collected/recorded or calculated, in this st
16、andard are regarded as the1These test methods are under the jurisdiction of ASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.03 on Texture,Plasticity and Density Characteristics of Soils.Current edition approved June 1, 2017. Published July 2017. Originally ap
17、provedin 1983. Last previous edition approved in 2010 as D4318 101. DOI: 10.1520/D4318-17E01.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard w
18、as developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1industry st
19、andard. 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 theusers objectives; and it is common practice to increase or
20、reduce significant digits 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 wi
21、th its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.11 This international standard was developed in accor-dance with internationally recognized
22、 principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C702 Practice for Reducing
23、 Samples ofAggregate to TestingSizeD75 Practice for Sampling AggregatesD420 Guide for Site Characterization for Engineering De-sign and Construction PurposesD653 Terminology Relating to Soil, Rock, and ContainedFluidsD1241 Specification for Materials for Soil-AggregateSubbase, Base, and Surface Cour
24、sesD2216 Test Methods for Laboratory Determination of Water(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
25、 PurposesD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4542 Test Methods for Pore Water Extraction and Deter-mination of the Soluble Salt Content of Soils by Refrac-tometerD4753 Guide for Evalua
26、ting, Selecting, and Specifying Bal-ances and Standard Masses 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 i
27、nASTM Test MethodsE691 Practice for Conducting an Interlaboratory 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. The definitions below appear in D653and are shown here for convenience. Th
28、e italic capital letter“D” indicates that the applicable units used to express the termare dimensionless.3.1.2 Atterberg Limitsin cohesive soils, originally, six“limits of consistency” of fine-grained soils were defined byAlbert Atterberg: the upper limit of viscous flow, the liquidlimit, the sticky
29、 limit, the cohesion limit, the plastic limit, andthe shrinkage limit. In current engineering usage, the termusually refers only to the liquid limit, plastic limit, and in somereferences, the shrinkage limit.3.1.3 liquid limit, LL, wLDin cohesive soils, the watercontent, in percent, of a soil at the
30、 arbitrarily defined boundarybetween the semi-liquid and plastic states.3.1.3.1 DiscussionThe undrained shear strength of soil atthe liquid limit is considered to be approximately 2 kPa (0.28psi).3.1.4 plastic limit, PL, wpDin cohesive soils, the watercontent, in percent, of a soil at the boundary b
31、etween the plasticand semi-solid states.3.1.5 plastic soila soil which has a range of water contentover which it exhibits plasticity and which will retain its shapeon drying.3.1.6 plasticity index, PIin cohesive soils, the range ofwater content over which a soil behaves plastically.Numerically, it i
32、s the difference between the liquid limit andthe plastic limit.3.1.7 consistencythe relative ease with which a soil can bedeformed.3.1.8 relative consistency, Ic,CrDin cohesive soils, theratio of: (1) the liquid limit minus the water content at a givencondition/state, to (2) the plasticity index.3.1
33、.9 liquidity index, ILDin cohesive soils, the ratio of:(1) the water content of a soil at a given condition/state minusits plastic limit, to (2) its plasticity index.3.1.10 activity number, Ain cohesive soils, the ratio of (1)the plasticity index of a soil to (2) the percent by mass ofparticles havi
34、ng an equivalent diameter smaller than 2 m.4. Summary of Test Methods4.1 The specimen is processed to remove any materialretained on a 425-m (No. 40) sieve.4.2 The liquid limit is determined by performing trials inwhich a portion of the specimen is spread in a brass cup,divided in two by a grooving
35、tool, and then allowed to flowtogether from the shocks caused by repeatedly dropping thecup in a standard mechanical devicefollowing either LiquidLimit Method A (Multipoint Method),orLiquid Limit MethodB (One-Point Method).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta
36、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.D4318 17124.3 The plastic limit is determined by alternately pressingtogether and rolling into a 3.2-mm (18-in.) diameter thread asmall po
37、rtion 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 reported as the plastic limit.4.4 The plasticity index is calculated as the differencebetween the liquid l
38、imit 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 soils (see Practices D2487 and D3282) andto specify the fine-grained fraction of construction materials(see
39、 Specification D1241). The liquid limit, plastic limit, andplasticity index of soils are also used extensively, eitherindividually or together, with other soil properties to correlatewith engineering behavior such as compressibility, hydraulicconductivity (permeability), compactibility, shrink-swell
40、, andshear strength. (See Section 6, Interferences.)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 todetermine its activit
41、y 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 shales susceptibility
42、 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 organic matter conten
43、t 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 considered capable of compe
44、tentand 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. Interferences6.1 The li
45、quid 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 are used to correlate orestimate the engineering behavior of soils in their natural moiststate, samples s
46、hould not be permitted to dry before testingunless data on dried samples are specifically desired. For thisreason Specimen Preparation Procedure 1 (Wet Preparation) isused unless Specimen Preparation Procedure 2 (Dry Prepara-tion) is specified by the requesting authority.6.2 The Liquid Limit Method
47、A (Multipoint Method) isgenerally more precise than the one-point method. It isrecommended that the Liquid Limit Method A (MultipointMethod) be used in cases where test results may be subject todispute, or where greater precision is required.6.3 Because the Liquid Limit Method B (One-Point Method)re
48、quires the operator to judge when the test specimen isapproximately at its liquid limit, it is particularly not recom-mended for use by inexperienced operators.6.4 The correlation on which the calculations of the LiquidLimit Method B (One-Point Method) are based may not bevalid for certain soils, su
49、ch as organic soils or soils from amarine environment. It is strongly recommended that the liquidlimit of these soils be determined by the Liquid Limit MethodA (Multipoint Method).6.5 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 Test Method D4542).Special consideration should therefore be given to soils from amarine environment or other sources where high soluble saltconcentrations may be present. The degree to which the saltspresent in
