1、Designation: D4221 11D4221 17Standard Test Method forDispersive Characteristics of Clay Soil by DoubleHydrometer1This standard is issued under the fixed designation D4221; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method, when used in conjunction with a test performed by Test Methodmethod provides an indication of then
3、atural dispersive characteristics of clay soils D422 on a duplicate soil sample, provides an indication of the natural dispersivecharacteristics of clay soils by comparing the amount of particles finer than 2-m as determined by this method compared to theamount of particles finer than 2-m as determi
4、ned by Test Method D7928(1).2 In order to do this comparison, two similarspecimens must be obtained from the sample.1.2 This test method follows the procedure given in Test Method D7928 with the exception that the soil slurry is notmechanically dispersed and no dispersing agent is added.1.3 This tes
5、t method is applicable only to soils with a plasticity index greater than 4 as determined inwhere the position of theplasticity index versus liquid limit plots (Test Methods D4318accordance with Test Method) falls on or D4318above the “A” line(Practice D2487) and more than 12 % of the soil fraction
6、is finer than 5-m2-m as determined in accordance with Test MethodD422D7928(2).1.3 This test method is similar toTest Method D422, except that this method covers the determination of percent of soil particlessmaller than 5-m in diameter in a soil-water suspension without mechanical agitation and to w
7、hich no dispersing agent has beenadded.1.4 The amount of particles smaller than 5-m determined by this method compared with the total amount of particles smallerthan 5-m determined by Test Method D422 is a measure of the dispersive characteristics of the soil.1.4 This Since this test method may not
8、identify all dispersive clay soils. Pinholes (Test Methodsoils, other tests such as, pinholedispersion (Test Methods D4647D4647/D4647M and crumb tests, or), crumb (Test Methods D6572both,) (3-5)or and the analysisof pore water extract extraction (Test Methods D4542) (4-67) may be performed individua
9、lly or used together to help verifydispersion.1.5 UnitsThe values stated in SI units are to be regarded as the standard. Reporting of test results in units other than SI shallnot be regarded as nonconformance with this test method.1.6 All observed and calculated values shall conform to the guideline
10、s for significant digits and rounding established in PracticeD6026.1.6.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industrystandard. In addition, they are representative of the significant digits that generally should be retain
11、ed. The procedures used do notconsider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the users objectives;and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations.It is be
12、yond the scope of this standard to consider significant digits used in analysis methods for engineering design.1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.7 This standard does not purport to address all of the safet
13、y concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1 This test method is under the jurisdiction of AST
14、M Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.06 on Physical-ChemicalInteractions of Soil and Rock.Current edition approved March 1, 2011July 1, 2017. Published March 2011July 2017. Originally approved in 1983. Last previous edition approved in 20052011 asD422
15、199(2005).D422111. DOI: 10.1520/D4221-11.10.1520/D4221-17.2 The boldface numbers in parentheses refer to the list of references appended to this standard.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to
16、 the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summa
17、ry 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 States11.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablis
18、hed in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D422 Test Method for Particle-Size Analysis of Soils (Withdrawn 20
19、16)4D653 Terminology Relating to Soil, Rock, and Contained FluidsD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2251D2487 Test Method for Metal Corrosion by Halogenated Organic Solvents and Their AdmixturesPractice forClassification of Soils for
20、Engineering Purposes (Unified Soil Classification System)D2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4220/D
21、4220M Practices for Preserving and Transporting Soil SamplesD4318 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of SoilsD4542 Test Methods for Pore Water Extraction and Determination of the Soluble Salt Content of Soils by RefractometerD4647D4647/D4647M Test MethodMethods for Id
22、entification and Classification of Dispersive Clay Soils by the Pinhole TestD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD6026 Practice for Using Significant Digits in Geotechnical DataE1D6572 Specification
23、 for ASTM Liquid-in-Glass ThermometersTest Methods for Determining Dispersive Characteristics ofClayey Soils by the Crumb TestE11D6913 Specification for Woven Wire Test Sieve Cloth and Test SievesTest Methods for Particle-Size Distribution(Gradation) of Soils Using Sieve AnalysisE100D7928 Specificat
24、ion for ASTM HydrometersTest Method for Particle-Size Distribution (Gradation) of Fine-Grained SoilsUsing the Sedimentation (Hydrometer) AnalysisE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 dispersive clayssoils that disperse (deflocculate
25、) easily and rapidly without significant mechanical assistance in waterof low-salt concentration.3.1.1.1 Such soils usually have a high proportion of their adsorptive capacity saturated with sodium cation although adsorbedlithium and magnesium may also play a role (7). Such soils also generally have
26、 a high shrink-swell potential, have low resistanceto erosion, and have low permeability in an intact state.3.1 For other definitions relating to this standard, refer to Terminology D653.Definitions:3.1.1 For definitions of common technical terms used in this standard, refer to Terminology D653.3.2
27、Definitions of Terms Specific to This Standard:3.2.1 dispersive clays, nsoils that deflocculate easily and rapidly without significant mechanical assistance in water of low-saltconcentration.3.2.1.1 DiscussionSuch soils usually have a high proportion of their adsorptive capacity saturated with sodiu
28、m cation although adsorbed lithium andmagnesium may also play a role (6). Such soils also generally have a high shrink-swell potential, have low resistance to erosion,and have low permeability in an intact state.4. Summary of Test Method4.1 The percent passing the 5-m size is determined first using
29、test procedures in Test Method D422.4.1 Then the percent passing the 5-m size is determined using the test procedures in this test method. This test method differsfrom This test method is used to determine the percent dispersion of a soil. In order to calculate the percent dispersion, two similarspe
30、cimens are obtained from a representative sample and then a sedimentation (hydrometer) analysis is performed on eachspecimen to determine the amount of particles finer than 2-m. The sedimentation analysis is performed following Test Method3 For referencedASTM standards, visit theASTM website, www.as
31、tm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D4221 172D422D7928 primarily in that no mechanical agitation nor chemical dispersants are used.for both specimens, except
32、that one of thespecimens is de-aired and is not mechanically or chemically dispersed.4.2 The percent dispersion is calculated by dividing the percent passing the 5-m size using this test method 2-m size fromthe de-aired, not dispersed specimen by the percent passing the 5-m size obtained using Test
33、Method2-m size from the specimenthat D422was dispersed and by multiplying the result by 100.5. Significance and Use5.1 Dispersive clays are those which normally deflocculate when exposed to water of low-salt concentration, the opposite ofaggregated clays that would remain flocculated in the same soi
34、l-water system (3, 4, 67). Generally, dispersive clays are highlyerosive, possibly subject to high shrink-swell potential, may have lower shear strength, and have lower permeability rates thanaggregated clays.5.2 When the percent dispersion equals 100, it indicates a completely dispersive clay-size
35、fraction. When the percent dispersionequals 0, it indicates completely nondispersive clay-size fraction.5.3 Available data (1) indicates that the test method has about 85 % reliance in predicting dispersive performance (85 % ofdispersive clays show more than 35 % dispersion).5.4 Since this test meth
36、od may not identify all dispersive clays, design decisions based solely on this test method may not beconservative. It is often run in conjunction with the crumb test (D6572) (4, 67) ,), the pinhole test given in Test Method(D4647D4647/D4647M,), or the analysis of the pore water extract (D4542) (4,
37、67), or combination thereof, to identify possibledispersive clay behavior.NOTE 1Notwithstanding the statement on precision and bias contained in this test method; the precision of this test method The quality of the resultproduced by this standard is dependent on the competence of the personal perfo
38、rming it, and the suitability of the equipment and facilities used.Agenciesthat meet the criteria of Practice D3740 are generally considered capable of competent and objective testing.testing/sampling/inspection/etc. Users of thistest method standard are cautioned that compliance with Practice D3740
39、 does not in itself ensureassure reliable testing.results. Reliable testingresultsdepends on severalmany factors; Practice D3740 provides a means of evaluating some of those factors.6. Apparatus6.1 SieveA2.00-mm (No. 10) sieve conforming to the requirements of Specification Section 6 of Test Method
40、E11D7928. Thephysical condition of sieves should be checked at least every 12 months. describes the equipment and tools needed for performingthe sedimentation (hydrometer) analysis portion of this standard.6.2 ContainersAirtight, for storing moist sample.6.2 Balance, Containermeeting the requirement
41、s of Class GP2 in SpecificationAn airtight, glass or equivalent inert containerwith D4753. Measurements should be verified every 12 months.enough capacity to hold the minus No. 10 (2.0-mm) specimen(s).6.3 Filtering FlaskA 500-mL filtering flask with a rubber stopper and a side tube capable of withst
42、anding a vacuum.6.5 Vacuum Pump, for evacuating entrapped air from the samples, and capable of pulling at least 20 to 25 in. Hg. Check pressureevery 12 months.6.6 Sedimentation CylinderA glass cylinder approximately 460 mm (18 in.) in height and 63.5 mm (2.5 in.) in diameter andmarked 360 6 20 mm fr
43、om the bottom of the inside for a volume of 1000 mL.6.7 HydrometerAnASTM hydrometer conforming to the requirements for Hydrometers 151H or 152H of Specification E100.Zero point should be checked every 12 months.6.8 Thermometer, accurate to 0.5C and conforming to Specification E1. In addition, thermo
44、metric devices such as ResistanceTemperature Detectors (RTDs), thermistors, thermocouples, and liquid-in-glass thermometers conforming to Test Method D2251,may be used. Zero point should be checked every 12 months.6.9 Timing DeviceA watch or clock capable of being read to the nearest second.6.10 Dis
45、tilled Water, with a pH 5.57.NOTE 2Trace minerals may be present in some Type IV water. However, since this is a qualitative test, such minerals should not affect the test results.6.4 Drying Oven, Vacuum System conforming to the requirements of Specification A vacuum pump or water aspirator E145.The
46、 oven should be thermostatically controlled, preferably of the forced-draft type, and capable of maintaining a uniformtemperature of 110 6 5C throughout the drying chamber. The temperature should be verified every four months.capable ofproducing a vacuum between 508 and 635 mm of Hg on the vacuum ga
47、uge.7. Reagents7.1 Section 7 of Test Method D7928 describes the reagents needed for performing the mechanically and chemically dispersedsedimentation (hydrometer) analysis portion of this standard.D4221 1737.2 Distilled WaterDistilled or demineralized water with a pH between 5.5 and 7 is the only pe
48、rmissible test fluid for use inthe sedimentation portion of the test. The use of tap water is not permitted.8. Sampling8.1 GeneralThis test method does not address, in any detail, procurement of the sample. It is assumed the sample is obtainedusing appropriate methods and is representative of the ma
49、terial under evaluation. The testing agency must preserve all samples inaccordance with Practice D4220/D4220M, Group B, except if the as-received sample does not meet those requirements. In whichcase, the water content of the sample does not have to be maintained. Section 9 of Test Method D6913 gives additional informationregarding sampling from different sources.8.2 Follow the steps given in 8.4 of Test Method D7928, including the mass requirements given in Table 1 of that standard, toobtain the reduced sample from which the test specimens are
