ASTM D6572-13
(Test Method)Standard Test Methods for Determining Dispersive Characteristics of Clayey Soils by the Crumb Test
Standard Test Methods for Determining Dispersive Characteristics of Clayey Soils by the Crumb Test
SIGNIFICANCE AND USE
5.1 The crumb test provides a simple, quick method for field or laboratory identification of a dispersive clayey soil. The internal erosion failures of a number of homogeneous earth dams, erosion along channel or canal banks, and rainfall erosion of earthen structures have been attributed to colloidal erosion along cracks or other flow channels formed in masses of dispersive clay (5).
5.2 The crumb test, as originally developed by Emerson (6), was called the aggregate coherence test and had seven different categories of soil-water reactions. Sherard (5) later simplified the test by combining some soil-water reactions so that only four categories, or grades, of soil dispersion are observed during the test. The crumb test is a relatively accurate positive indicator of the presence of dispersive properties in a soil. The crumb test, however, is not a completely reliable negative indicator that soils are not dispersive. The crumb test can seldom be relied upon as a sole test method for determining the presence of dispersive clays. The double-hydrometer test (Test Method D4221) and pinhole test (Test Method D4647) are test methods that provide valuable additional insight into the probable dispersive behavior of clay soils.Note 2—The quality of the result produced by these test methods is dependent on the competence of the personnel performing it, 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. Users of these test methods are cautioned that compliance with Practice D3740 does not in itself ensure reliable testing. Reliable testing depends on several factors; Practice D3740 provides a means of evaluating some of those factors.
SCOPE
1.1 Two test methods are provided to give a qualitative indication of the natural dispersive characteristics of clayey soils:. Method A and Method B.
1.1.1 Method A—Procedure for Natural Soil Crumbs described in 10.2.
1.1.2 Method B—Procedure for Remolded Soil Crumbs described in 10.3.
1.2 The crumb test, while a good, quick indication of dispersive soil, should usually be run in conjunction with a pinhole test and a double hydrometer test, Test Methods A6 and A5, respectively.
1.3 The crumb test has some limitations in its usefulness as an indicator of dispersive soil. A dispersive soil may sometimes give a non-dispersive reaction in the crumb test. Soils containing kaolinite with known field dispersion problems, have shown non-dispersive reactions in the crumb test (1).2 However, if the crumb test indicates dispersion, the soil is probably dispersive.
1.4 These test methods are not applicable for soils with 12 % or less of the particles passing 0.005 mm and having a plasticity index less than or equal to 8, as determined by Test Method A9.
1.5 Oven-dried soil should not be used to prepare crumb test specimens, as irreversible changes could occur to the soil pore-water physicochemical properties responsible for dispersion (2).Note 1—In some cases, the results of the pinhole, crumb, and double-hydrometer test methods may disagree. The crumb test is a better indicator of dispersive soils than of non-dispersive soils (3).
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.6.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to ...
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Designation: D6572 − 13
StandardTest Methods for
Determining Dispersive Characteristics of Clayey Soils by
1
the Crumb Test
This standard is issued under the fixed designation D6572; 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* 1.6.1 Theproceduresusedtospecifyhowdataarecollected/
recorded or calculated in this standard are regarded as the
1.1 Two test methods are provided to give a qualitative
industry standard. In addition, they are representative of the
indication of the natural dispersive characteristics of clayey
significant digits that generally should be retained. The proce-
soils:. Method A and Method B.
dures used do not consider material variation, purpose for
1.1.1 Method A—Procedure for Natural Soil Crumbs de-
obtaining the data, special purpose studies, or any consider-
scribed in 10.2.
ations for the user’s objectives; and it is common practice to
1.1.2 Method B—Procedure for Remolded Soil Crumbs
increase or reduce significant digits of reported data to be
described in 10.3.
commensuratewiththeseconsiderations.Itisbeyondthescope
1.2 The crumb test, while a good, quick indication of
of this standard to consider significant digits used in analytical
dispersive soil, should usually be run in conjunction with a
methods for engineering design.
pinhole test and a double hydrometer test, Test Methods A6
1.7 The values stated in SI units are to be regarded as
and A5, respectively.
standard. No other units of measurement are included in this
1.3 The crumb test has some limitations in its usefulness as
standard.
anindicatorofdispersivesoil.Adispersivesoilmaysometimes
1.8 This standard does not purport to address all of the
give a non-dispersive reaction in the crumb test. Soils contain-
safety concerns, if any, associated with its use. It is the
ing kaolinite with known field dispersion problems, have
2 responsibility of the user of this standard to establish appro-
shown non-dispersive reactions in the crumb test (1).
priate safety and health practices and determine the applica-
However, if the crumb test indicates dispersion, the soil is
bility of regulatory limitations prior to use.
probably dispersive.
2. Referenced Documents
1.4 These test methods are not applicable for soils with 12
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% or less of the particles passing 0.005 mm and having a
2.1 ASTM Standards:
plasticity index less than or equal to 8, as determined by Test
D653 Terminology Relating to Soil, Rock, and Contained
Method A9.
Fluids
D1193 Specification for Reagent Water
1.5 Oven-driedsoilshouldnotbeusedtopreparecrumbtest
D2216 Test Methods for Laboratory Determination of Water
specimens, as irreversible changes could occur to the soil
(Moisture) Content of Soil and Rock by Mass
pore-water physicochemical properties responsible for disper-
D3740 Practice for Minimum Requirements for Agencies
sion (2).
Engaged in Testing and/or Inspection of Soil and Rock as
NOTE 1—In some cases, the results of the pinhole, crumb, and
Used in Engineering Design and Construction
double-hydrometer test methods may disagree. The crumb test is a better
D4221 Test Method for Dispersive Characteristics of Clay
indicator of dispersive soils than of non-dispersive soils (3).
Soil by Double Hydrometer
1.6 All observed and calculated values shall conform to the
D4318 Test Methods for Liquid Limit, Plastic Limit, and
guidelines for significant digits and rounding established in
Plasticity Index of Soils
Practice D6026.
D4647 Test Method for Identification and Classification of
Dispersive Clay Soils by the Pinhole Test
1
These test methods are under the jurisdiction ofASTM Committee D18 on Soil
D6026 Practice for Using Significant Digits in Geotechnical
and Rock and are the direct responsibility of Subcommittee D18.06 on Physical-
Data
Chemical Interactions of Soil and Rock
Current edition approved Nov. 1, 2013. Published November 2013. Originally
3
approved in 2006. Last previous edition approved in 2012 as D4186 – 12. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/D6572-13. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6572 − 13
E1 Specification for ASTM Li
...
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: D6572 − 12 D6572 − 13
Standard Test Methods for
Determining Dispersive Characteristics of Clayey Soils by
1
the Crumb Test
This standard is issued under the fixed designation D6572; 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*
1.1 Two test methods are provided to give a qualitative indication of the natural dispersive characteristics of clayey soils. Test
soils:. Method A is for natural soil clumps and Test Method B for remolded soil.and Method B.
1.1.1 Method A—Procedure for Natural Soil Crumbs described in 10.2.
1.1.2 Method B—Procedure for Remolded Soil Crumbs described in 10.3.
1.2 These test methods are not applicable for soils with less than 12 % finer than 0.005 mm and with a plasticity index less than
or equalThe crumb test, while a good, quick indication of dispersive soil, should usually be run in conjunction with a pinhole test
and a double hydrometer test, Test Methods A6 toand A58., respectively.
1.3 The crumb test method has some limitations in its usefulness as an indicator of dispersive clay.soil. A dispersive soil may
sometimes give a non-dispersive reaction in the crumb test. Soils containing kaolinite with known field dispersion problems, have
2
shown non-dispersive reactions in the crumb test (1). However, if the crumb test indicates dispersion, the soil is probably
dispersive.
1.4 Oven-dried soil should not be used to prepare crumb test specimens, as irreversible changes could occur to the soil
pore-water physicochemical properties responsible for dispersionThese test methods are not applicable for soils with 12 % or less
of the particles passing 0.005 mm and having a (plasticity2). index less than or equal to 8, as determined by Test Method A9.
1.5 The crumb test method, while a good quick indication of dispersive clay, should usually be run in conjunctionOven-dried
soil should not be used to prepare crumb test specimens, as irreversible changes could occur to the soil pore-water physicochemical
properties responsible for dispersion with (2a ).pinhole test and a double hydrometer test, Test Methods D4647 and D4221,
respectively.
NOTE 1—In some cases, the results of the pinhole, crumb, and double-hydrometer test methods may disagree. Crumb test methods are The crumb test
is a better indicator of dispersive clayssoils than of nondispersive claysnon-dispersive soils (3).
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.6.1 The methodprocedures used to specify how data are collected, calculated, collected/recorded or recordedcalculated in this
standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies
the results obtained using this standard is beyond its scope.are regarded as the industry standard. In addition, they are representative
of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for
obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase
or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard
to consider significant digits used in analytical methods for engineering design.
1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information
only.standard. No other units of measurement are included in this standard.
1.8 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 and health practices and determine the applicability of regulatory
limitations prior to use.
1
These test methods are under the jurisdiction of ASTM Committee D18 on Soil and Rock and are the direct responsibility of Subcommittee D18.06 on Physical-Chemical
Interactions of Soil and Rock
Current edition approved Nov. 1, 2012Nov. 1, 2013. Published December 2012November 2013. Originally approved in 2006. Last previous edition approved in 20062012
as D4186 – 06.D4186 – 12. DOI: 10.1520/D6572-12.10.1520/D6572-13.
2
The boldface numbers in parentheses
...
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