1、Designation: D 4318 05Standard Test Methods forLiquid Limit, Plastic Limit, and Plasticity Index of Soils1This standard is issued under the fixed designation D 4318; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 determinati
3、on 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
4、specified 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 soi
5、ls 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, Multipoin
6、t test 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 metho
7、d. 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 reco
8、mmended 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
9、 multipoint 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
10、consistency 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 D 2216). Specialconsideration should therefore be given to soils from a marineenvironment or
11、other 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.T
12、herefore, 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 acceptable metric units are to beregarded as the standard, except as noted below. The valuesgiv
13、en in parentheses are for information only.1.8.1 The standard units for the resilience tester covered inAnnex A1 are inch-pound, not metric. The metric values givenare for information only.1.9 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
14、 theresponsibility 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:2C 702 Practice for Reducing Field Samples of Aggregate toTesting SizeD75 Practice f
15、or Sampling AggregatesD 420 Guide to Site Characterization for Engineering, De-sign, and Construction PurposesD 653 Terminology Relating to Soil, Rock, and ContainedFluids1This standard is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D
16、18.03 on Texture, Plasticityand Density Characteristics of Soils.Current edition approved March 1, 2005. Published April 2005. Originallyapproved in 1983. Last previous edition approved in 2000 as D 4318 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
17、 Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.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
18、 19428-2959, United States.D 1241 Specification for Materials for Soil-Aggregate Sub-base, Base, and Surface CoursesD 2216 Test Method for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD 2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Cla
19、ssification System)D 3282 Practice for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction PurposesD 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionD 4753 Specification
20、 for Evaluating, Selecting, and Speci-fying Balances and Scales for Use in Soil, Rock, andRelated Construction Materials TestingD 6026 Practice for Using Significant Digits in Geotechni-cal DataE11 Specification for Wire-Cloth Sieves for Testing Pur-posesE 177 Practice for Use of the Terms Precision
21、 and Bias inASTM Test MethodsE 691 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 D 653.3.1.2 Atterberg LimitsOriginally, six “limits of consis-tency”
22、 of fine-grained soils were defined by Albert Atterberg:the upper limit of 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 referen
23、ces, the shrinkagelimit.3.1.3 consistencythe relative ease with which a soil 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 l
24、iquid limit is considered to be approximately 2 kPa (0.28psi).3.1.5 plastic 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 retai
25、n its shapeon drying.3.1.7 plasticity index (PI)the range of water content 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 pla
26、stic limit, to (2) itsplasticity index.3.1.9 activity number (A)the ratio of (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. 4
27、0) sieve. The liquid limit isdetermined by performing trials in which a portion 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 limi
28、t, MethodA, requires three ormore trials over a range of water contents to 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
29、 by a correction factor todetermine the liquid limit.4.2 The plastic limit 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 bepre
30、ssed together and re-rolled. The water content of the soil atthis point is 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 severalenginee
31、ring classification systems to characterize the fine-grained fractions of soils (see Practices D 2487 and D 3282)and to specify the fine-grained fraction of construction mate-rials (see Specification D 1241). The liquid limit, plastic limit,and plasticity index of soils are also used extensively, ei
32、therindividually or together, with other soil properties to correlatewith engineering behavior such as compressibility, hydraulicconductivity (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 re
33、lative consistency orliquidity index. In addition, the plasticity index and thepercentage finer than 2-m particle size can be used todetermine its activity number.5.3 These methods are sometimes used to evaluate theweathering characteristics of clay-shale materials. When sub-jected to repeated wetti
34、ng and drying cycles, the liquid limitsof these materials tend to increase. The amount of increase isconsidered to be a measure of a shales susceptibility toweathering.5.4 The liquid limit of a soil containing substantial amountsof organic matter decreases dramatically when the soil isoven-dried bef
35、ore testing. Comparison of the liquid limit of asample before and after oven-drying can therefore be used as aqualitative measure of organic matter content of a soil (seePractice D 2487).NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performi
36、ng it and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740, generally, are considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D 3740 does not in itself a
37、ssurereliable results. Reliable results depend on many factors; Practice D 3740provides a means of evaluating some of those factors.D 4318 0526. Apparatus6.1 Liquid Limit DeviceA mechanical device consistingof a brass cup suspended from a carriage designed to control itsdrop onto a hard rubber base.
38、 Fig. 1 shows the essentialfeatures and critical dimensions of the device. The device maybe operated by either a hand crank or electric motor.6.1.1 BaseAhard rubber base having a Type D Durometerhardness of 80 to 90, and resilience rebound of at least 77 %but no more than 90 %. Conduct resilience te
39、sts on the finishedbase with the feet attached. Details for measuring the resilienceof the base are given in Annex A1.6.1.2 Rubber Feet, supporting the base, designed to provideisolation of the base from the work surface, and having a TypeA Durometer hardness no greater than 60 as measured on thefin
40、ished feet attached to the base.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 rotation, without developing an upward ordownward velocity of the cup when th
41、e 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 hasno velocity at drop off. Other cam designs also provide this feature andm
42、ay 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 cam rotation.6.1.5 Carriage, constructed in a way that allows convenientbu
43、t 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 aremovable pin. See Fig. 2 for definition and determination ofthe height-of-drop of the cup.6.1.6 Motor Drive (Optional)As an a
44、lternative 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 isolated from therest of the device by rubber mounts or in some other way thatprevents vibration from the motor being trans
45、mitted 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 using a motor-drivendevice must not differ from those obtained using a manuallyoperated device.6.2 Flat Grooving ToolA too
46、l 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 gage for adjusting the height-of-drop of theliquid limit device.NOTE 3Prior to the adoption of th
47、is test method, a curved groovingtool was specified as part of the apparatus for performing the liquid limittest. The curved tool is not considered to be as accurate as the flat toolFIG. 1 Hand-Operated Liquid Limit DeviceD 4318 053described in 6.2 since it does not control the depth of the soil in
48、the liquidlimit cup. However, there are some data which indicate that typically theliquid limit is slightly increased when the flat tool is used instead of thecurved tool.6.3 GageA metal gage block for adjusting the height-of-drop of the cup, having the dimensions shown in Fig. 4. Thedesign of the t
49、ool may vary provided the gage will rest securelyon the base without being susceptible to rocking, and the edgewhich contacts the cup during adjustment is straight, at least 10mm (38 in.) wide, and without bevel or radius.6.4 Water Content ContainersSmall corrosion-resistantcontainers with snug-fitting lids for water content specimens.Aluminum or stainless steel cans 2.5 cm (1 in.) high by 5 cm(2 in.) in diameter are appropriate.6.5 Balance, conforming to Specification D 4753, ClassGP1 (readability of 0.01 g).6.6 Mixing and Storage ContainerA container
