1、Designation:D482921Standard Test Method forExpansion Index of Soils1This standard is issued under the fixed designation D4829;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
2、 the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method allows for determination of expansionpotential of soils when inundated with distilled water.2This testmethod measures a qualitative index property of th
3、e soil ratherthan a design parameter to be used for calculation of the actualamount of expansion.The expansion index,EI,provides anindication of swelling potential of a soil.1.2 This test method provides a simple,yet sensitive,method for evaluation of expansion potential of soils forpractical engine
4、ering applications using an index parameter.1.3 UnitsThe values stated in SI units are to be regardedas standard.The values given in parentheses are provided forinformation only and are not considered standard.Reporting oftest results in units other than SI shall not be regarded asnonconformance wit
5、h this standard.1.3.1 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units.In the system,the pound(lbf)represents a unit of force(weight),while the units formass is slugs.The slug unit is not given,unless dynamic(F=ma)calculations are involved.1.3.2 The SI units pre
6、sented for apparatus are substitutionsof the inch-pound units,other similar SI units should beacceptable providing they meet the technical requirementsestablished by the inch-pound apparatus.1.3.3 It is common practice in the engineering/constructionprofession to concurrently use pounds to represent
7、 both a unitof mass(lbm)and of force(lbf).This practice implicitlycombines two separate systems of units;the absolute and thegravitational systems.It is scientifically undesirable to com-bine the use of two separate sets of inch-pound units within asingle standard.As stated,this standard includes th
8、e gravita-tional system of inch-pound units and does not use/present theslug unit of mass.However,the use of balances and scalesrecording pounds of mass(lbm)or recording density in lbm/ft3shall not be regarded as nonconformance with this standard.1.3.4 The terms density and unit weight are often use
9、dinterchangeably.Density is mass per unit volume,whereas unitweight is force per unit volume.In this standard,density isgiven only in SI units.After the density has been determined,the unit weight is calculated in SI or inch-pound units,or both.1.4 All observed and calculated values shall conform to
10、 theguidelines for significant digits and rounding established inPractice D6026,unless superseded by this test method.1.4.1 For purposes of comparing a measured or calculatedvalue(s)with specified limits,the measured or calculatedvalue(s)shall be rounded to the nearest decimal of significantdigits i
11、n the specified limit.1.4.2 The procedures used to specify how data are collected/recorded or calculated in the 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 v
12、ariation,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
13、 digits used in analysismethods for engineering data.1.5 The text of this standard references notes and footnotesthat provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.1.6 This standard does not purport
14、 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.1.7 This international standard was de
15、veloped 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.1This test method
16、is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved Jan.1,2021.Published January 2021.Originallyapproved in 1995.Last previous edition approved in 2019 as D482919.DOI:10.1520/D4829-21.2Anderson,J.N.,and Lade,P.V.,“The Expansion Index Test,”GeotechnicalTesting Journal,Vol 4,No.2,ASTM,1981,pp.5867.*A Summary of Changes section appears at the end of this standardCopyri
