ASTM D7503-18
(Test Method)Standard Test Method for Measuring the Exchange Complex and Cation Exchange Capacity of Inorganic Fine-Grained Soils
Standard Test Method for Measuring the Exchange Complex and Cation Exchange Capacity of Inorganic Fine-Grained Soils
SIGNIFICANCE AND USE
4.1 Fine-grained soils are used in waste containment systems as barriers to flow and contaminant transport. Liquids contained by these barriers can contain ions that may interact with the mineral surfaces in fine-grained soils.
4.2 The liquid passing through the pores of fine-grained soil can interact with the mineral surface, and affect the physical and chemical characteristics of the soil. This method can be used as part of an evaluation of these interactions.
Note 1: The quality of the result produced by this standard depends on the competence of the personnel performing the test and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors. Practice D3740 provides a means of evaluating some of these factors.
SCOPE
1.1 This test method describes the procedures for measuring the soluble and bound cations as well as the cation exchange capacity (CEC) of fine-grained inorganic soils. Clay minerals in fine-grained soils carry a negative surface charge that is balanced by bound cations near the mineral surface. These bound cations can be exchanged by other cations in the pore water, which are referred to as soluble cations. The cation exchange capacity is a measure of the negative surface charge on the mineral surface. The CEC generally is satisfied by calcium (Ca), sodium (Na), magnesium (Mg), and potassium (K), although other cations may be present depending on the environment in which the soil exists. This test method was developed from concepts described previously in Lavkulich (1981) (1)2 and Rhoades (1982) (2). In soils with appreciable gypsum or calcite, dissolution of these minerals will release Ca in solution that may affect the measurement.
1.2 In this test method, the soluble salts from the mineral surface are washed off with de-ionized water and then the concentration of soluble salts within the extract is measured. The bound cations of the clay are measured by using a solution containing an index ion that forces the existing cations in the bound layer into solution. The total concentrations of bound and soluble cations in this solution are measured. The CEC is measured by displacing the index ion with another salt solution and measuring the amount of the displaced index ion.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026. The procedures in Practice D6026 that are used to specify how data are collected, recorded, and calculated are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the objectives of the user. Increasing or reducing the significant digits of reported data to be commensurate with these considerations is common practice. Consideration of the significant digits to be used in analysis methods for engineering design is beyond the scope of this standard.
1.5 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.
1.6 This international standard was developed in accordance with internati...
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7503 − 18
Standard Test Method for
Measuring the Exchange Complex and Cation Exchange
1
Capacity of Inorganic Fine-Grained Soils
This standard is issued under the fixed designation D7503; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* specify how data are collected, recorded, and calculated are
regarded as the industry standard. In addition, they are repre-
1.1 This test method describes the procedures for measuring
sentative of the significant digits that should generally be
the soluble and bound cations as well as the cation exchange
retained. The procedures do not consider material variation,
capacity (CEC) of fine-grained inorganic soils. Clay minerals
purpose for obtaining the data, special purpose studies, or any
in fine-grained soils carry a negative surface charge that is
considerations for the objectives of the user. Increasing or
balanced by bound cations near the mineral surface. These
reducing the significant digits of reported data to be commen-
bound cations can be exchanged by other cations in the pore
surate with these considerations is common practice. Consid-
water, which are referred to as soluble cations. The cation
eration of the significant digits to be used in analysis methods
exchange capacity is a measure of the negative surface charge
for engineering design is beyond the scope of this standard.
on the mineral surface. The CEC generally is satisfied by
calcium (Ca), sodium (Na), magnesium (Mg), and potassium 1.5 Units—The values stated in SI units are to be regarded
(K), although other cations may be present depending on the as standard. No other units of measurement are included in this
environment in which the soil exists. This test method was standard. Reporting of test results in units other than SI shall
developed from concepts described previously in Lavkulich not be regarded as nonconformance with this test method.
2
(1981) (1) and Rhoades (1982) (2). In soils with appreciable
1.6 This international standard was developed in accor-
gypsum or calcite, dissolution of these minerals will release Ca
dance with internationally recognized principles on standard-
in solution that may affect the measurement.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.2 In this test method, the soluble salts from the mineral
mendations issued by the World Trade Organization Technical
surface are washed off with de-ionized water and then the
Barriers to Trade (TBT) Committee.
concentration of soluble salts within the extract is measured.
The bound cations of the clay are measured by using a solution
2. Referenced Documents
containing an index ion that forces the existing cations in the
3
2.1 ASTM Standards:
bound layer into solution. The total concentrations of bound
D653 Terminology Relating to Soil, Rock, and Contained
and soluble cations in this solution are measured. The CEC is
Fluids
measured by displacing the index ion with another salt solution
D1193 Specification for Reagent Water
and measuring the amount of the displaced index ion.
D2216 Test Methods for Laboratory Determination of Water
1.3 This standard does not purport to address all of the
(Moisture) Content of Soil and Rock by Mass
safety concerns, if any, associated with its use. It is the
D3740 Practice for Minimum Requirements for Agencies
responsibility of the user of this standard to establish appro-
Engaged in Testing and/or Inspection of Soil and Rock as
priate safety, health, and environmental practices and deter-
Used in Engineering Design and Construction
mine the applicability of regulatory limitations prior to use.
D4753 Guide for Evaluating, Selecting, and Specifying Bal-
1.4 All observed and calculated values shall conform to the
ances and Standard Masses for Use in Soil, Rock, and
guide for significant digits and rounding established in Practice
Construction Materials Testing
D6026. The procedures in Practice D6026 that are used to
D6026 Practice for Using Significant Digits in Geotechnical
Data
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
E145 Specification for Gravity-Convection and Forced-
Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic
Ventilation Ovens
Properties and Hydraulic Barriers.
Current edition approved March 1, 2018. Published March 2018. Originally
3
apporved in 2010. Last previous edition approved in 2010 as D
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7503 − 10 D7503 − 18
Standard Test Method for
Measuring the Exchange Complex and Cation Exchange
1
Capacity of Inorganic Fine-Grained Soils
This standard is issued under the fixed designation D7503; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This test method describes the procedures for measuring the soluble and bound cations as well as the cation exchange
capacity (CEC) of fine-grained inorganic soils. Clay minerals in fine-grained soils carry a negative surface charge that is balanced
by bound cations near the mineral surface. These bound cations can be exchanged by other cations in the pore water, which are
referred to as soluble cations. The cation exchange capacity is a measure of the negative surface charge on the mineral surface.
The CEC generally is satisfied by calcium (Ca), sodium (Na), magnesium (Mg), and potassium (K), although other cations may
be present depending on the environment in which the soil exists. This test method was developed from concepts described
2
previously in Lavkulich (1981) (1) and Rhoades (1982) (2). In soils with appreciable gypsum or calcite, dissolution of these
minerals will release Ca in solution that may affect the measurement.
1.2 In this test method, the soluble salts from the mineral surface are washed off with de-ionized water and then the
concentration of soluble salts within the extract is measured. The bound cations of the clay are measured by using a solution
containing an index ion that forces the existing cations in the bound layer into solution. The total concentrations of bound and
soluble cations in this solution are measured. The CEC is measured by displacing the index ion with another salt solution and
measuring the amount of the displaced index ion.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice
D6026. The procedures in Practice D6026 that are used to specify how data are collected, recorded, and calculated are regarded
as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The
procedures do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for
the objectives of the user. Increasing or reducing the significant digits of reported data to be commensurate with these
considerations is common practice. Consideration of the significant digits to be used in analysis methods for engineering design
is beyond the scope of this standard.
1.5 Units—The values stated in SI units are to be regarded as the standard, unless standard. No other units are specifically
given.of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as
nonconformance with this test method.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
3
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D1193 Specification for Reagent Water
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic Properties
and Hydraulic Barriers.
Current edition approved July 1, 2010March 1, 2018. Published August 2010March 2018. Originally apporved in 2010. Last previous edition approved in 2010 as
D7503–10. DOI: 10.1520/D7503-1010.1520/D7503–18.
2
The boldface numbers in parentheses refer to a list of references at the end of this standard.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume informati
...
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