ASTM_D_4221_-_18.pdf

Designation:D422118Standard 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 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 provides an indication of the naturaldispersive characteristics of clay soils by comparing theamount of particles finer than 2-m as determined by thismethod compared to the amount of particles finer than 2-m asdetermined by Test Method D7928(1).2In order to do thiscomparison,two similar specimens must be obtained from thesample.1.2 This test method follows the procedure given in TestMethod D7928 with the exception that the soil slurry is notmechanically dispersed and no dispersing agent is added.1.3 This test method is applicable only to soils where theposition of the plasticity index versus liquid limit plots(TestMethods D4318)falls on or above the“A”line(PracticeD2487)and more than 12%of the soil fraction is finer than2-m as determined in accordance with Test Method D7928(2).1.4 Since this test method may not identify all dispersiveclay soils,other tests such as,pinhole dispersion(Test MethodsD4647/D4647M),crumb(Test Methods D6572)(3-5)and theanalysis of pore water extraction(Test Methods D4542)(4-7)may be performed individually or used together to help verifydispersion.1.5 UnitsThe values stated in SI units are to be regardedas the standard.Reporting of test results in units other than SIshall not be regarded as nonconformance with this test method.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6.1 The procedures used to specify how data are collected/recorded or calculated,in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.7 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized 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:3D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2216 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)D2488 Practice for Description and Identification of Soils(Visual-Manual Procedures)D3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4220/D4220M Practices for Preserving and TransportingSoil SamplesD4318 Test Methods for Liquid Limit,Plastic Limit,andPlasticity Index of SoilsD4542 Test Methods for Pore Water Extraction and Deter-mination of the Soluble Salt Content of Soils by Refrac-tometer1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.06 on Physical-ChemicalInteractions of Soil and Rock.Current edition approved Jan.1,2018.Published February 2018.Originallyapproved in 1983.Last previous edition approved in 2017 as D422117.DOI:10.1520/D4221-18.2The boldface numbers in parentheses refer to the list of references appended tothis standard.3For referenced 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.*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 was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and