ASTM D3282-93(2004)e1
(Classification)Standard Practice for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes
Standard Practice for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes
SCOPE
1.1 This practice covers a procedure for classifying mineral and organomineral soils into seven groups based on laboratory determination of particle-size distribution, liquid limit, and plasticity index. It may be used when a precise engineering classification is required, especially for highway construction purposes. Evaluation of soils within each group is made by means of a group index, which is a value calculated from an empirical formula.
Note 1—The group classification, including the group index, should be useful in determining the relative quality of the soil material for use in earthwork structures, particularly embankments, subgrades, subbases, and bases. However, for the detailed design of important structures, additional data concerning strength or performance characteristics of the soil under field conditions will usually be required.
1.2 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.
1.3 This practice offers a set of instructions for performing one or more specific operations. This practice cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This practice is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this practice be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process.
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Designation: D 3282 – 93 (Reapproved 2004)
Standard Practice for
Classification of Soils and Soil-Aggregate Mixtures for
Highway Construction Purposes
This standard is issued under the fixed designation D 3282; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Added keywords editorially in May 2004.
1. Scope 2. Referenced Documents
1.1 This practice covers a procedure for classifying mineral 2.1 ASTM Standards:
and organomineral soils into seven groups based on laboratory D 420 Guide to Site Characterization for Engineering, De-
determination of particle-size distribution, liquid limit, and sign, and Construction Purposes
plasticity index. It may be used when a precise engineering D 421 Practice for Dry Preparation of Soil Samples for
classification is required, especially for highway construction Particle-Size Analysis and Determination of Soil Con-
purposes. Evaluation of soils within each group is made by stants
means of a group index, which is a value calculated from an D 422 Test Method for Particle-Size Analysis of Soils
empirical formula. D 653 Terminology Relating to Soil, Rock, and Contained
Fluids
NOTE 1—Thegroupclassification,includingthegroupindex,shouldbe
D 1140 Test Methods forAmount of Material in Soils Finer
useful in determining the relative quality of the soil material for use in
Than the No. 200 (75-µm) Sieve
earthwork structures, particularly embankments, subgrades, subbases, and
bases. However, for the detailed design of important structures, additional D 1452 Practice for Soil Investigation and Sampling by
data concerning strength or performance characteristics of the soil under
Auger Borings
field conditions will usually be required.
D 1586 Test Method for Penetration Test and Split-Barrel
Sampling of Soils
1.2 This standard does not purport to address all of the
D 1587 Practice for Thin-Walled Tube Sampling of Soils
safety concerns, if any, associated with its use. It is the
for Geotechnical Purposes
responsibility of the user of this standard to establish appro-
D 2217 Practice for Wet Preparation of Soil Samples for
priate safety and health practices and determine the applica-
Particle-Size Analysis and Determination of Soil Con-
bility of regulatory limitations prior to use.
stants
1.3 This practice offers a set of instructions for performing
D 4318 Test Methods for Liquid Limit, Plastic Limit, and
one or more specific operations. This practice cannot replace
Plasticity Index of Soils
education or experience and should be used in conjunction
2.2 AASHTO Document:
with professional judgment. Not all aspects of this practice may
M 145 The Classification of Soils and Soil Aggregate Mix-
be applicable in all circumstances. This practice is not
tures for Highway Construction Purposes
intended to represent or replace the standard of care by which
the adequacy of a given professional service must be judged,
3. Terminology
nor should this practice be applied without consideration of a
3.1 Definitions of Terms Specific to This Standard:
project’s many unique aspects. The word “Standard” in the
title of this document means only that the document has been
approved through the ASTM consensus process.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This standard is under the jurisdiction of ASTM Committee D18 on Soil and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Rock and is the direct responsibility of Subcommittee D18.07 on Identification and Standards volume information, refer to the standard’s Document Summary page on
Classification of Soils. the ASTM website.
Current edition approved May 1, 2004. Published May 2004. Originally Available from American Association of State Highway and Transportation
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approved in 1973. Last previous edition approved in 1997 as D 3282 – 93 (1997) . Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 3282 – 93 (2004)
3.1.1 The following terms are frequently used in this prac- 7.1.3 Separate the field sample into two fractions on a 3-in.
tice. These terms differ slightly from those given in Terminol- (75-mm) sieve,
ogy D 653, but are used here to maintain consistency with 7.1.4 Weigh the fraction retained on the 3-in. (75-mm)
common highway usage. sieve.Computethepercentageofplus3-in.materialinthefield
3.1.2 boulders—rock fragments, usually rounded by weath- sample, and note this percentage as auxiliary information, and
ering or abrasion, that will be retained on a 3-in. (75-mm) 7.1.5 Thoroughly mix the fraction passing the 3-in. (75-
sieve. mm) sieve and select the test samples.
3.1.3 coarse sand—particles of rock or soil that will pass a
NOTE 2—Ifvisualexaminationindicatesthatnobouldersizematerialis
No. 10 (2-mm) sieve and be retained on a No. 40 (425-µm)
present, omit 7.1.3 and 7.1.4.
sieve.
7.2 Prepare the test sample in accordance with Practices
3.1.4 fine sand—particles of rock or soil that will pass a No.
D 421 or D 2217. Determine the percentage of the sample finer
40 (425-µm) sieve and be retained on a No. 200 (75-µm) sieve.
than a No. 10 (2-mm) sieve.
3.1.5 gravel—particles of rock that will pass a 3-in. (75-
mm) sieve and be retained on a No. 10 (2-mm) sieve. NOTE 3—It is recommended that the method for wet preparation be
used for soils containing organic matter or irreversible mineral colloids.
3.1.6 silt-clay (combined silt and clay)—fine soil and rock
particles that will pass a No. 200 (75-µm) sieve.
8. Testing Procedure
3.1.7 silty—fine-grained material that has a plasticity index
8.1 Determine the percentage of the test sample finer than a
of 10 or less.
No. 200 (75-µm) sieve in accordance with Test Methods
3.1.8 clayey—fine-grained material that has a plasticity
D 1140 or D 422.
index of 11 or more.
NOTE 4—Forgranularmaterials,thepercentageofthesamplefinerthan
4. Significance and Use
a No. 40 (425-µm) sieve must also be determined.
4.1 The practice described classifies soils from any geo-
8.2 Determine the liquid limit and the plasticity index of a
graphic location into groups (including group indexes) based
portion of the test sample passing a No. 40 (425-µm) sieve in
on the results of prescribed laboratory tests to determine the
accordance with Test Methods D 4318.
particle-size characteristics, liquid limit, and plasticity index.
9. Classification Procedure
4.2 Theassigningofagroupsymbolandgroupindexcanbe
used to aid in the evaluation of the significant properties of the
9.1 Using the test data determined in Section 8, classify the
soil for highway and airfield purposes.
soil into the appropriate group or subgroup, or both, in
4.3 The various groupings of this classification system
accordance with Table 1 or Table 2. Use Fig. 1 to classify
correlate in a general way with the engineering behavior of
silt-clay materials on the basis of liquid limit and plasticity
soils.Also, in a general way, the engineering behavior of a soil
index values.
varies inversely with its group index. Therefore, this practice
NOTE 5—All limiting values are shown as whole numbers. If fractional
provides a useful first step in any field or laboratory investi-
numbers appear on test reports, convert to the nearest whole numbers for
gation for geotechnical engineering purposes.
the purpose of classification.
9.1.1 Withtherequiredtestdataavailable,proceedfromleft
5. Apparatus
to right in Table 1 or Table 2 and the correct classification will
5.1 Apparatus for Preparation of Samples—See Practices
befoundbytheprocessofelimination.Thefirstgroupfromthe
D 421 or D 2217.
left into which the test data will fit is the correct classification.
5.2 Apparatus for Particle-Size Analysis—See Test Meth-
NOTE 6—Classification of materials in the various groups applies only
ods D 1140 and D 422.
to the fraction passing the 3-in. (75-mm) sieve. Therefore, any specifica-
5.3 Apparatus for Liquid Limit and Plastic Limit Tests—See
tion regarding the use ofA-1,A-2, orA-3 materials in construction should
Test Methods D 4318.
state whether boulders (retained on 3-in. sieve) are permitted.
6. Sampling
10. Description of Classification Groups
6.1 Conductfieldinvestigationsandsamplinginaccordance
10.1 Granular Materials, containing 35 % or less passing
with one or more of the following procedures:
the No. 200 (75-µm) sieve:
6.1.1 Guide D 420,
10.1.1 Group A-1—The typical material of this group is a
6.1.2 Practice D 1452,
well-graded mixture of stone fragments or gravel, coarse sand,
6.1.3 Test Method D 1586, and
fine sand, and a nonplastic or feebly-plastic soil binder.
6.1.4 Practice D 1587.
However, this group also includes stone fragments, gravel,
coarse sand, volcanic cinders, etc., without a soil binder.
7. Test Sample
10.1.1.1 SubgroupA-1-aincludesthosematerialsconsisting
7.1 Test samples shall represent that portion of the field predominantly of stone fragments or gravel, either with or
sample finer than the 3-in. (75-mm) sieve and shall be obtained without a well-graded binder of fine material.
as follows: 10.1.1.2 SubgroupA-1-bincludesthosematerialsconsisting
7.1.1 Air-dry the field sample, predominantly of coarse sand, either with or without a well-
7.1.2 Weigh the field sample, graded soil binder.
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D 3282 – 93 (2004)
TABLE 1 Classification of Soils and Soil-Aggregate Mixtures
Granular Materials Silt-Clay Materials
General Classification
(35 % or less passing No. 200) (More than 35 % passing No. 200)
A
Group Classification A-1 A-3 A-2 A-4 A-5 A-6 A-7
Sieve analysis, % passing:
No. 10 (2.00 mm) . . . . . . .
No. 40 (425 µm) 50 max 51 min . . . . .
No. 200 (75 µm) 25 max 10 max 35 max 36 min 36 min 36 min 36 min
Characteristics of fraction passing No. 40
(425 µm):
B
Liquid limit . . 40 max 41 min 40 max
B
Plasticity index 6 max N.P. 10 max 10 max 11min41min
11 min
General rating as subgrade Excellent to Good Fair to Poor
A
The placing of A-3 before A-2 is necessary in the “left to right elimination process” and does not indicate superiority of A-3 over A-2.
B
See Table 2 for values.
Reprinted with permission of American Association of State Highway and Transportation Officials
TABLE 2 Classification of Soils and Soil-Aggregate Mixtures
Granular Materials Silt-Clay Materials
General Classification
(35 % or less passing No. 200) (More than 35 % passing No. 200)
A-1 A-2 A-7
Group classification A-3 A-4 A-5 A-6
A-7-5,
A-1-
...
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