ASTM D4221-99(2005)

Standard Test Method for Dispersive Characteristics of Clay Soil by Double Hydrometer

SIGNIFICANCE AND USE
Dispersive clays are those which normally deflocculate when exposed to water of low-salt concentration, the opposite of aggregated clays that would remain flocculated in the same soil-water system  (3, 4, 7). Generally, dispersive clays are highly erosive, possibly subject to high shrink-swell potential, may have lower shear strength, and have lower permeability rates than aggregated clays.
Available data (1) indicates that the test method has about 85 % reliance in predicting dispersive performance (85 % of dispersive clays show more than 35 % dispersion).
Since this test method may not identify all dispersive clays, design decisions based solely on this test method may not be conservative. It is often run in conjunction with the crumb test (4, 7), the pinhole test given in Test Method D 4647, or the analysis of pore water extract (4, 7), or combination thereof, to identify possible dispersive clay behavior.
Note 1—Notwithstanding the statement on precision and bias contained in this test method; the precision of this test method is dependent on the competence of the personal performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective testing. Users of this test method are cautioned that compliance with Practice D 3740 does not in itself ensure reliable testing. Reliable testing depends on several factors; Practice D 3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This test method, when used in conjunction with a test performed by Test Method D 422 on a duplicate soil sample, provides an indication of the natural dispersive characteristics of clay soils ().
1.2 This test method is applicable only to soils with a plasticity index greater than 4 as determined in accordance with Test Method D 4318 and more than 12 % of the soil fraction finer than 5-m as determined in accordance with Test Method D 422 ().
1.3 This test method is similar to Test Method D 422, except that this method covers the determination of percent of soil particles smaller than 5-m in diameter in a soil-water suspension without mechanical agitation and to which no dispersing agent has been added.
1.4 The amount of particles smaller than 5-m determined by this method compared with the total amount of particles smaller than 5-m determined by Test Method D 422 is a measure of the dispersive characteristics of the soil.
1.5 This test method may not identify all dispersive clay soils. Pinholes (Test Method D 4647 and crumb tests, or both, ()or the analysis of pore water extract () may be performed to help verify dispersion.
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.

General Information

• Status: Historical
• Publication Date: 31-May-2005
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.06 - Physical-Chemical Interactions of Soil and Rock

Relations

• Replaces: ASTM D4221-99 - Standard Test Method for Dispersive Characteristics of Clay Soil by Double Hydrometer
• Effective Date: 01-Jun-2005
• Replaced By: ASTM D4221-11 - Standard Test Method for Dispersive Characteristics of Clay Soil by Double Hydrometer
• Effective Date: 01-Mar-2011
• Referred By: ASTM D4647/D4647M-13(2020) - Standard Test Methods for Identification and Classification of Dispersive Clay Soils by the Pinhole Test
• Effective Date: 01-Jun-2005
• Referred By: ASTM D6572-21 - Standard Test Methods for Determining Dispersive Characteristics of Clayey Soils by the Crumb Test
• Effective Date: 01-Jun-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4221–99 (Reapproved 2005)
Standard Test Method for
Dispersive Characteristics of Clay Soil by Double
Hydrometer
This standard is issued under the fixed designation D4221; 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 D653 Terminology Relating to Soil, Rock, and Contained
Fluids
1.1 This test method, when used in conjunction with a test
D2216 Test Methods for Laboratory Determination of Wa-
performed by Test Method D422 on a duplicate soil sample,
ter (Moisture) Content of Soil and Rock by Mass
provides an indication of the natural dispersive characteristics
D3740 Practice for Minimum Requirements for Agencies
of clay soils (1).
Engaged in Testing and/or Inspection of Soil and Rock as
1.2 This test method is applicable only to soils with a
Used in Engineering Design and Construction
plasticity index greater than 4 as determined in accordance
D4318 Test Methods for Liquid Limit, Plastic Limit, and
with Test Method D4318 and more than 12 % of the soil
Plasticity Index of Soils
fraction finer than 5-µm as determined in accordance with Test
D4647 Test Method for Identification and Classification of
Method D422 (2).
Dispersive Clay Soils by the Pinhole Test
1.3 This test method is similar toTest Method D422, except
D4753 Guide for Evaluating, Selecting, and Specifying
that this method covers the determination of percent of soil
Balances and Standard Masses for Use in Soil, Rock, and
particles smaller than 5-µm in diameter in a soil-water suspen-
Construction Materials Testing
sion without mechanical agitation and to which no dispersing
E1 Specification for ASTM Liquid-in-Glass Thermometers
agent has been added.
E11 SpecificationforWovenWireTestSieveClothandTest
1.4 The amount of particles smaller than 5-µm determined
Sieves
by this method compared with the total amount of particles
E100 Specification for ASTM Hydrometers
smaller than 5-µm determined by Test Method D422 is a
E145 Specification for Gravity-Convection and Forced-
measure of the dispersive characteristics of the soil.
Ventilation Ovens
1.5 This test method may not identify all dispersive clay
soils. Pinholes (Test Method D4647 and crumb tests, or both,
3. Terminology
(3-5)or the analysis of pore water extract (4-7) may be
3.1 Definitions:
performed to help verify dispersion.
3.1.1 dispersive clays—soils that disperse (deflocculate)
1.6 This standard does not purport to address all of the
easily and rapidly without significant mechanical assistance in
safety concerns, if any, associated with its use. It is the
water of low-salt concentration.
responsibility of the user of this standard to establish appro-
3.1.1.1 Such soils usually have a high proportion of their
priate safety and health practices and determine the applica-
adsorptive capacity saturated with sodium cation although
bility of regulatory limitations prior to use.
adsorbed lithium and magnesium may also play a role (6).
2. Referenced Documents Such soils also generally have a high shrink-swell potential,
havelowresistancetoerosion,andhavelowpermeabilityinan
2.1 ASTM Standards:
intact state.
D422 Test Method for Particle-Size Analysis of Soils
3.2 For other definitions relating to this standard, refer to
Terminology D653.
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.06 on Physico-Chemical
4. Summary of Test Method
Properties of Soils and Rocks.
4.1 The percent passing the 5-µm size is determined using
Current edition approved June 1, 2005. Published December 2005. Originally
approved in 1983. Last previous edition approved in 1999 as D4221 – 99. DOI:
test procedures in Test Method D422.
10.1520/D4221-99R05.
4.2 The percent passing the 5-µm size is determined using
The boldface numbers in parentheses refer to the list of references appended to
the test procedures in this test method. This test method differs
this standard.
from Test Method D422 primarily in that no mechanical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
agitation nor chemical dispersants are used.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4221–99 (2005)
However,sincethisisaqualitativetest,suchmineralsshouldnotaffectthe
4.3 The percent dispersion is calculated by dividing the
test results.
percent passing the 5-µm size using this test method by the
percent passing the 5-µm size obtained using Test Method
6.11 Drying Oven,conformingtotherequirementsofSpeci-
D422 and by multiplying the result by 100.
fication E145. The oven should be thermostatically controlled,
preferably of the forced-draft type, and capable of maintaining
5. Significance and Use
a uniform temperature of 110 6 5°C throughout the drying
5.1 Dispersive clays are those which normally deflocculate
chamber. The temperature should be verified every four
when exposed to water of low-salt concentration, the opposite
months.
of aggregated clays that would remain flocculated in the same
soil-water system (3, 4, 7). Generally, dispersive clays are
7. Sample Preparation
highly erosive, possibly subject to high shrink-swell potential,
7.1 Sieve approximately 200 g of soil through a 2.00-mm
may have lower shear strength, and have lower permeability
(No. 10) sieve. If materials are quite moist, this may require
rates than aggregated clays.
hand rubbing or use of a rubber-tipped pestle to force material
5.2 Available data (1) indicates that the test method has
through the sieve. It is recommended that this test be per-
about 85 % reliance in predicting dispersive performance
formed at natural water content. When samples are very moist,
(85 % of dispersive clays show more than 35 % dispersion).
they should be dried to about the plastic limit before proceed-
5.3 Since this test method may not identify all dispersive
ing with the test.
clays, design decisions based solely on this test method may
7.2 Collect a representative sample of about 100 g of
not be conservative. It is often run in conjunction with the
material passing the No. 10 sieve for water content determi-
crumb test (4, 7), the pinhole test given inTest Method D4647,
nation and retain the remainder of the minus No. 10 material in
or the analysis of pore water extract (4, 7), or combination
an airtight container.
thereof, to identify possible dispersive clay behavior.
7.3 Determine the water content of the minus No. 10
NOTE 1—Notwithstanding the statement on precision and bias con-
material in accordance with Test Method D2216.
tained in this test method; the precision of this test method is dependent
on the competence of the personal performing it, and the suitability of the
8. Procedure
equipment and facilities used. Agencies that meet the criteria of Practice
8.1 Obtain 50 g of oven-dried soil in accordance with 7.3.
D3740 are generally considered capable of competent and objective
testing. Users of this test method are cautioned that compliance with
Determine the percent passing 5 µm in accordance with Test
Practice D3740 does not in itself ensure reliable testing. Reliable testing
Method D422.
depends on seve
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