1、Designation: D 4221 99 (Reapproved 2005)Standard Test Method forDispersive Characteristics of Clay Soil by DoubleHydrometer1This standard is issued under the fixed designation D 4221; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method, when used in conjunction with a testperformed by Test Method D 422 on a duplicate soil
3、 sample,provides an indication of the natural dispersive characteristicsof clay soils (1).21.2 This test method is applicable only to soils with aplasticity index greater than 4 as determined in accordancewith Test Method D 4318 and more than 12 % of the soilfraction finer than 5-m as determined in
4、accordance with TestMethod D 422 (2).1.3 This test method is similar to Test Method D 422, exceptthat this method covers the determination of percent of soilparticles smaller than 5-m in diameter in a soil-water suspen-sion without mechanical agitation and to which no dispersingagent has been added.
5、1.4 The amount of particles smaller than 5-m determinedby this method compared with the total amount of particlessmaller than 5-m determined by Test Method D 422 is ameasure of the dispersive characteristics of the soil.1.5 This test method may not identify all dispersive claysoils. Pinholes (Test M
6、ethod D 4647 and crumb tests, or both,(3-5)or the analysis of pore water extract (4-7) may beperformed to help verify dispersion.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish
7、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 422 Test Method for Particle-Size Analysis of SoilsD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 2216 Test Method for Labora
8、tory Determination of Water(Moisture) Content of Soil and RockD 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionD 4318 Test Method for Liquid Limit, Plastic Limit, andPlasticity Index of SoilsD
9、4647 Test Method for Identification and Classification ofDispersive Clay Soils by the Pinhole TestD 4753 Specification for Evaluating, Selecting, and Speci-fying Balances and Scales for Use in Testing Soil, Rock,and Related Construction MaterialsE1 Specification for ASTM ThermometersE11 Specificatio
10、n for Wire-Cloth Sieves for Testing Pur-posesE 100 Specification for ASTM HydrometersE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 dispersive clayssoils that disperse (deflocculate)easily and rapidly without significant mechanical assistan
11、ce inwater of low-salt concentration.3.1.1.1 Such soils usually have a high proportion of theiradsorptive capacity saturated with sodium cation althoughadsorbed lithium and magnesium may also play a role (6).Such soils also generally have a high shrink-swell potential,have low resistance to erosion,
12、 and have low permeability in anintact state.3.2 For other definitions relating to this standard, refer toTerminology D 653.4. Summary of Test Method4.1 The percent passing the 5-m size is determined usingtest procedures in Test Method D 422.4.2 The percent passing the 5-m size is determined usingth
13、e test procedures in this test method. This test method differsfrom Test Method D 422 primarily in that no mechanicalagitation nor chemical dispersants are used.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.06 on
14、 Physico-ChemicalProperties of Soils and Rocks.Current edition approved June 1, 2005. Published December 2005. Originallyapproved in 1983. Last previous edition approved in 1999 as D 4221 99.2The boldface numbers in parentheses refer to the list of references appended tothis standard.3For referenced
15、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
16、hohocken, PA 19428-2959, United States.4.3 The percent dispersion is calculated by dividing thepercent passing the 5-m size using this test method by thepercent passing the 5-m size obtained using Test MethodD 422 and by multiplying the result by 100.5. Significance and Use5.1 Dispersive clays are t
17、hose which normally deflocculatewhen exposed to water of low-salt concentration, the oppositeof aggregated clays that would remain flocculated in the samesoil-water system (3, 4, 7). Generally, dispersive clays arehighly erosive, possibly subject to high shrink-swell potential,may have lower shear s
18、trength, and have lower permeabilityrates than aggregated clays.5.2 Available data (1) indicates that the test method hasabout 85 % reliance in predicting dispersive performance(85 % of dispersive clays show more than 35 % dispersion).5.3 Since this test method may not identify all dispersiveclays,
19、design decisions based solely on this test method maynot be conservative. It is often run in conjunction with thecrumb test (4, 7), the pinhole test given in Test Method D 4647,or the analysis of pore water extract (4, 7), or combinationthereof, to identify possible dispersive clay behavior.NOTE 1No
20、twithstanding the statement on precision and bias con-tained in this test method; the precision of this test method is dependenton the competence of the personal performing it, and the suitability of theequipment and facilities used. Agencies that meet the criteria of PracticeD 3740 are generally co
21、nsidered capable of competent and objectivetesting. Users of this test method are cautioned that compliance withPractice D 3740 does not in itself ensure reliable testing. Reliable testingdepends on several factors; Practice D 3740 provides a means of evalu-ating some of those factors.6. Apparatus6.
22、1 SieveA 2.00-mm (No. 10) sieve conforming to therequirements of Specification E11. The physical condition ofsieves should be checked at least every 12 months.6.2 ContainersAirtight, for storing moist sample.6.3 Balance, meeting the requirements of Class GP2 inSpecification D 4753. Measurements shou
23、ld be verified every12 months.6.4 Filtering FlaskA 500-mL filtering flask with a rubberstopper and a side tube capable of withstanding a vacuum.6.5 Vacuum Pump, for evacuating entrapped air from thesamples, and capable of pulling at least 20 to 25 in. Hg. Checkpressure every 12 months.6.6 Sedimentat
24、ion CylinderA glass cylinder approxi-mately 460 mm (18 in.) in height and 63.5 mm (2.5 in.) indiameter and marked 360 6 20 mm from the bottom of theinside for a volume of 1000 mL.6.7 HydrometerAn ASTM hydrometer conforming to therequirements for Hydrometers 151H or 152H of SpecificationE 100. Zero p
25、oint should be checked every 12 months.6.8 Thermometer, accurate to 0.5C and conforming toSpecification E1. Zero point should be checked every 12months.6.9 Timing DeviceA watch or clock capable of being readto the nearest second.6.10 Distilled Water, with a pH 5.57.NOTE 2Trace minerals may be presen
26、t in some Type IV water.However, since this is a qualitative test, such minerals should not affect thetest results.6.11 Drying Oven, conforming to the requirements of Speci-fication E 145. The oven should be thermostatically controlled,preferably of the forced-draft type, and capable of maintaininga
27、 uniform temperature of 110 6 5C throughout the dryingchamber. The temperature should be verified every fourmonths.7. Sample Preparation7.1 Sieve approximately 200 g of soil through a 2.00-mm(No. 10) sieve. If materials are quite moist, this may requirehand rubbing or use of a rubber-tipped pestle t
28、o force materialthrough the sieve. It is recommended that this test be per-formed at natural water content. When samples are very moist,they should be dried to about the plastic limit before proceed-ing with the test.7.2 Collect a representative sample of about 100 g ofmaterial passing the No. 10 si
29、eve for water content determi-nation and retain the remainder of the minus No. 10 material inan airtight container.7.3 Determine the water content of the minus No. 10material in accordance with Test Method D 2216.8. Procedure8.1 Obtain 50 g of oven-dried soil in accordance with 7.3.Determine the per
30、cent passing 5 m in accordance with TestMethod D 422.8.2 Place approximately 125 mL of distilled water in thefiltering flask.8.3 Obtain from the container of minus No. 10 moist soil, arepresentative sample equivalent to 25.0 g of oven-dry soil, bysplitting or other appropriate means, and place into
31、the filteringflask with the distilled water.8.3.1 Determine the mass of moist soil equivalent to 25.0 gof dry soil as follows:Wm5 Wd3S1.0 1w100D(1)where:Wm= mass moist soil, g,Wd= mass oven-dried soil, g, andw = water content of sample, %.8.4 Place a rubber stopper into the mouth of the filteringfla
32、sk and connect the flask to the vacuum pump. If the soil isdry, it should be soaked for a minimum of 2 h before thefiltering flask is connected to the vacuum pump. Under mostconditions, 20 to 23 in. Hg is sufficient to de-air the sample.8.5 Start vacuum pump and apply full vacuum. If bubblesdo not a
33、ppear, the vacuum is insufficient.8.6 At 3 min, 5 min, and 8 min after application of vacuum,swirl the flask several times in a rotating manner to assist inremoving entrapped air.8.7 Disconnect the flask from the vacuum after a totalevacuation time of 10 min.8.8 Wash the soil-water suspension from t
34、he flask into thesedimentation cylinder and add Type IV water until the totalvolume is 1000 mL.D 4221 99 (2005)28.9 Using the palm of the hand over the open end of thecylinder (or a rubber stopper in the open end), shake thecylinder end over end for a period of 1 min (see Note 3).At theend of 1 min,
35、 set the cylinder in a convenient location andrecord the time. This is the start of the sedimentation period.The time interval between step 8.5 and step 8.9 should notexceed 1 h.NOTE 3The number of turns during the minute should be approxi-mately 60, counting the turn upside down and back as two tur
36、ns. Any soilremaining in the bottom of the cylinder during the first few turns shouldbe loosened by shaking the cylinder while it is in the inverted position.8.10 Take hydrometer and temperature readings necessaryto determine the percent of material finer than 5-m insuspension using procedures and c
37、alculations described in TestMethod D 422.NOTE 4It should be recognized that the hydrometer compositecorrection described in Test Method D 422 must be made using Type IVwater instead of a solution of dispersing agent.9. Calculation9.1 Calculate percent dispersion from:% Dispersion 5% passing 52m in
38、this test% passing 52m in Test Method D 4223 100(2)10. Report10.1 Report results as percent dispersion of the 5-m (5micron) fraction.NOTE 5When the percent dispersion equals 100, it indicates acompletely dispersive clay-sized fraction. When the percent dispersionequals 0, it indicates completely non
39、dispersive.11. Precision and Bias11.1 Precision:11.1.1 Single-Operator PrecisionThe single-operator co-efficient of variation has been found to be 3.9 %. Therefore,results of two properly conducted tests by the same operatorwith the same equipment should not be considered suspectunless they differ b
40、y more than 11.1 % of their mean.11.1.2 Multilaboratory PrecisionAn interlaboratory testprogram is being conducted to determine a multilaboratoryprecision statement.As soon as this data has been collected andanalyzed, this test method will be revised to include a precisionstatement for multilaborato
41、ry precision.11.2 BiasThere is no accepted reference value for this testmethod; therefore, bias cannot be determined.12. Keywords12.1 clays; deflocculation; dispersion; dispersive clay; ero-sion; gradation; hydrometer analysis; jugging; particle size;pipingREFERENCES(1) Decker, R. S., and Dunnigan,
42、L. P.,“ Development and Use of the SoilConservation Service Dispersion Test,” Dispersive Clays, RelatedPiping, and Erosion in Geotechnical Projects, ASTM STP 623, 1977,pp. 94109.(2) Ryker, N. L., “Encountering Dispersive Clays on Soil ConservationService Projects in Oklahoma,” Dispersive Clays, Rela
43、ted Piping, andErosion in Geotechnical Projects, ASTM STP 623 , 1977, pp. 370389.(3) Volk, G. M., “Method of Determination of Degree of Dispersion of theClay Fraction of Soils,” Proceedings, Soil Science Society ofAmerica,Vol II, 1937, p. 561.(4) Sherard, J. L., Decker, R. S., and Ryker, N. L., “Pip
44、ing in Earth Damsof Dispersive Clay,” Proceedings of the Speciality Conference onPerformance of Earth Supported Structures,American Society of CivilEngineers, 1972.(5) Holmgram, G.C.S., and Flanagan, C.P., “Factors Affecting Spontane-ous Dispersion of Soil Materials as Evidenced by the Crumb Test,”S
45、ymposium on Dispersive Clays, Related Piping, and Erosion inGeotechnical Projects, ASTM STP 623, ASTM, 1977, p. 218-239.(6) Bell, J.G., and Maude, R.R., “Dispersive Soils: A Review from theSouthAfrica Perspective,” Quarterly Journal of Engineering Geology,Vol 27, 1994, pp. 195-210.(7) Sherard, J. L.
46、, Dunnigan, L. P., and Decker, R. S., “Some EngineeringProblems with Dispersive Clay,” Dispersive Clays, Related Piping,and Erosion in Geotechnical Projects, ASTM STP 623, 1977, pp. 312.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any
47、item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical c
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49、a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e
