1、Designation:D750310Standard Test Method forMeasuring the Exchange Complex and Cation ExchangeCapacity of Inorganic Fine-Grained Soils1This standard is issued under the fixed designation D7503;the number immediately following the designation indicates the year oforiginal adoption or,in the case of re
2、vision,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.Scope1.1 This test method describes the procedures for measuringthe soluble and bound cations as well as the cati
3、on exchangecapacity(CEC)of fine-grained inorganic soils.Clay mineralsin fine-grained soils carry a negative surface charge that isbalanced by bound cations near the mineral surface.Thesebound cations can be exchanged by other cations in the porewater,which are referred to as soluble cations.The cati
4、onexchange capacity is a measure of the negative surface chargeon the mineral surface.The CEC generally is satisfied bycalcium(Ca),sodium(Na),magnesium(Mg),and potassium(K),although other cations may be present depending on theenvironment in which the soil exists.This test method wasdeveloped from c
5、oncepts described previously in Lavkulich(1981)(1)2and Rhoades(1982)(2).In soils with appreciablegypsum or calcite,dissolution of these minerals will release Cain solution that may affect the measurement.1.2 In this test method,the soluble salts from the mineralsurface are washed off with de-ionized
6、 water and then theconcentration of soluble salts within the extract is measured.The bound cations of the clay are measured by using a solutioncontaining an index ion that forces the existing cations in thebound layer into solution.The total concentrations of boundand soluble cations in this solutio
7、n are measured.The CEC ismeasured by displacing the index ion with another salt solutionand measuring the amount of the displaced index ion.1.3 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 e
8、stablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 All observed and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026.The procedures in Practice D6026 that are used t
9、ospecify how data are collected,recorded,and calculated areregarded as the industry standard.In addition,they are repre-sentative of the significant digits that should generally beretained.The procedures do not consider material variation,purpose for obtaining the data,special purpose studies,or any
10、considerations for the objectives of the user.Increasing orreducing the significant digits of reported data to be commen-surate with these considerations is common practice.Consid-eration of the significant digits to be used in analysis methodsfor engineering design is beyond the scope of this stand
11、ard.1.5 The values stated in SI units are to be regarded as thestandard,unless other units are specifically given.2.Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil,Rock,and ContainedFluidsD1193 Specification for Reagent WaterD2216 Test Methods for Laboratory Determination o
12、f Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataE145 Specification for Gravity-Convec
13、tion and Forced-Ventilation Ovens3.Terminology3.1 For definitions of other terms used in this standard,seeTerminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 acid wash,nthe process of initially rinsing equip-ment with tap water,followed by a rinse with 10%HNO3solution,and then
14、finally rinsing 3 times with DI water.3.2.2 bound cations(BC),ncations that are adsorbed(bound)to mineral surfaces that may be exchanged.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.04 on HydrologicProperties an
15、d Hydraulic Barriers.Current edition approved July 1,2010.Published August 2010.DOI:10.1520/D7503-102The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serv
16、iceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 cation exchange capacity(CEC),nthe total negativecharge on mineral surface to be satisfied by bound cations.3.2.4 exchange complex,nthe collection of bound cationssatisfying the CEC.3.2.5 fine-grained soils,nany soil with more than 50%passing the No.200 US
