1、Designation: D4221 11Standard 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 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.1. Scope*1.1 This test method, when used in conjunction with a testperformed by Test Method D422 on a duplicate soil sample,provides an i
3、ndication 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 D4318 and more than 12 % of the soilfraction finer than 5-m as determined in accordance with TestMe
4、thod D422 (2).1.3 This test method is similar to Test Method D422, 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.1.4 The amount of partic
5、les smaller than 5-m determinedby this method compared with the total amount of particlessmaller than 5-m determined by Test Method D422 is ameasure of the dispersive characteristics of the soil.1.5 This test method may not identify all dispersive claysoils. Pinholes (Test Method D4647 and crumb tes
6、ts, or both,(3-5)or the analysis of pore water extract (4-7) may beperformed to help verify dispersion.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.7 The values stated in SI units are to be regarded as thesta
7、ndard. The values given in parentheses are for informationonly.1.8 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 appro-priate safety and health practices and determine the applic
8、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D422 Test Method for Particle-Size Analysis of SoilsD653 Terminology Relating to Soil, Rock, and ContainedFluidsD2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by
9、MassD2251 Test Method for Metal Corrosion by HalogenatedOrganic Solvents and Their AdmixturesD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4318 Test Methods for Liquid Limit, Plastic Limit, andP
10、lasticity Index of SoilsD4647 Test Method for Identification and Classification ofDispersive Clay Soils by the Pinhole TestD4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD6026 Practice for Using Significant Di
11、gits in GeotechnicalDataE1 Specification for ASTM Liquid-in-Glass ThermometersE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE100 Specification for ASTM HydrometersE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 dispersive cl
12、ayssoils that disperse (deflocculate)easily and rapidly without significant mechanical assistance inwater of low-salt concentration.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.06 on Physical-ChemicalInteraction
13、s of Soil and Rock.Current edition approved March 1, 2011. Published March 2011. Originallyapproved in 1983. Last previous edition approved in 2005 as D422199(2005).DOI: 10.1520/D4221-11.2The boldface numbers in parentheses refer to the list of references appended tothis standard.3For referenced AST
14、M 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.1*A Summary of Changes section appears at the end of this standard.Copyright AST
15、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 ha
16、ve a high shrink-swell potential,have low resistance to erosion, and have low permeability in anintact state.3.2 For other definitions relating to this standard, refer toTerminology D653.4. Summary of Test Method4.1 The percent passing the 5-m size is determined firstusing test procedures in Test Me
17、thod D422.4.2 Then the percent passing the 5-m size is determinedusing the test procedures in this test method. This test methoddiffers from Test Method D422 primarily in that no mechanicalagitation nor chemical dispersants are used.4.3 The percent dispersion is calculated by dividing thepercent pas
18、sing the 5-m size using this test method by thepercent passing the 5-m size obtained using Test MethodD422 and by multiplying the result by 100.5. Significance and Use5.1 Dispersive clays are those which normally deflocculatewhen exposed to water of low-salt concentration, the oppositeof aggregated
19、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 strength, and have lower permeabilityrates than aggregated clays.5.2 Available data (1) indicates that the t
20、est 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, design decisions based solely on this test method maynot be conservative. It is often run in conjunction wi
21、th thecrumb test (4, 7), the pinhole test given in Test Method D4647,or the analysis of the pore water extract (4, 7), or combinationthereof, to identify possible dispersive clay behavior.NOTE 1Notwithstanding the statement on precision and bias con-tained in this test method; the precision of this
22、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 PracticeD3740 are generally considered capable of competent and objectivetesting. Users of this test method are cautioned that complian
23、ce withPractice D3740 does not in itself ensure reliable testing. Reliable testingdepends on several factors; Practice D3740 provides a means of evaluat-ing some of those factors.6. Apparatus6.1 SieveA 2.00-mm (No. 10) sieve conforming to therequirements of Specification E11. The physical condition
24、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 D4753. Measurements should be verified every12 months.6.4 Filtering FlaskA 500-mL filtering flask with a rubberstopper and a side tu
25、be 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 Sedimentation CylinderA glass cylinder approxi-mately 460 mm (18 in.) in height and 63.5 mm (2.5 in.) indiameter and m
26、arked 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 SpecificationE100. Zero point should be checked every 12 months.6.8 Thermometer, accurate to 0.5C and conforming toSpecification E1. I
27、n addition, thermometric devices such asResistance Temperature Detectors (RTDs), thermistors, ther-mocouples, and liquid-in-glass thermometers conforming toTest Method D2251, may be used. Zero point should bechecked every 12 months.6.9 Timing DeviceA watch or clock capable of being readto the neares
28、t second.6.10 Distilled 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 thetest results.6.11 Drying Oven, conforming to the requirements of Speci-fication E145. The oven should be thermostatica
29、lly controlled,preferably of the forced-draft type, and capable of maintaininga 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 a
30、re quite moist, this may requirehand rubbing or use of a rubber-tipped pestle to 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
31、Collect a representative sample of about 100 g ofmaterial passing the No. 10 sieve 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 D2216.8. Proced
32、ure8.1 Obtain 50 g of oven-dried soil in accordance with 7.3.Determine the percent passing 5 m in accordance with TestMethod D422.8.2 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.
33、0 g of oven-dry soil, bysplitting or other appropriate means, and place into 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 wdxS1.0 1w100D(1)D4221 112where:wm= mass moist soil, g,wd= mass oven-dried soil, g, andw = wa
34、ter content of sample, %.8.4 Place a rubber stopper into the mouth of the filteringflask 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 sufficien
35、t to de-air the sample.8.5 Start vacuum pump and apply full vacuum. If bubblesdo not appear, 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 v
36、acuum after a totalevacuation time of 10 min.8.8 Wash the soil-water suspension from the flask into thesedimentation cylinder and add Type IV water until the totalvolume is 1000 mL.8.9 Using the palm of the hand over the open end of thecylinder (or a rubber stopper in the open end), shake thecylinde
37、r end over end for a period of 1 min (see Note 3).At theend of 1 min, 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
38、 approxi-mately 60, counting the turn upside down and back as two turns. 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 p
39、ercent of material finer than 5-m insuspension using procedures and calculations described in TestMethod D422.NOTE 4It should be recognized that the hydrometer compositecorrection described in Test Method D422 must be made using Type IVwater instead of a solution of dispersing agent.9. Calculation9.
40、1 Calculate percent dispersion from:% Dispersion 5% passing 52m in this test% passing 52m in Test Method D4223 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
41、. When the percent dispersionequals 0, it indicates completely nondispersive.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 s
42、ame equipment should not be considered suspectunless they differ by more than 11.1 % of their mean.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; hydrome
43、ter analysis; jugging; particle size;pipingREFERENCES(1) Decker, R. S., and Dunnigan, 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 Disp
44、ersive Clays on Soil ConservationService Projects in Oklahoma,” Dispersive Clays, Related Piping,and Erosion 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 ofA
45、merica, Vol II, 1937, p. 561.(4) Sherard, J. L., Decker, R. S., and Ryker, N. L., “Piping 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
46、 Affecting Spontane-ous Dispersion of Soil Materials as Evidenced by the Crumb Test,”Symposium 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 theSouth Africa Perspective,
47、” Quarterly Journal of Engineering Geol-ogy, Vol 27, 1994, pp. 195-210.(7) Sherard, J. L., 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.D4221 113SUMMARY OF CHANG
48、ESCommittee D18 has identified the location of selected changes to this test method since the last issue,D422199(2005), that may impact the use of this test method. (Approved March 1, 2011)(1) Added new 1.6 referencing Practice D6026, new 1.7concerning use of SI units, and renumbered subsequent para
49、-graphs.(2) Deleted 11.1.2 on Multilaboratory Precision.(3) Added reference to Test Method D422 in Eq 2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any 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 committee and must be reviewed every
