1、Designation: D 3282 93 (Reapproved 2004)e1Standard Practice forClassification of Soils and Soil-Aggregate Mixtures forHighway Construction Purposes1This standard is issued under the fixed designation D 3282; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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.e1NOTEAdded
3、 keywords editorially in May 2004.1. Scope1.1 This practice covers a procedure for classifying mineraland organomineral soils into seven groups based on laboratorydetermination of particle-size distribution, liquid limit, andplasticity index. It may be used when a precise engineeringclassification i
4、s required, especially for highway constructionpurposes. Evaluation of soils within each group is made bymeans of a group index, which is a value calculated from anempirical formula.NOTE 1The group classification, including the group index, should beuseful in determining the relative quality of the
5、soil material for use inearthwork structures, particularly embankments, subgrades, subbases, andbases. However, for the detailed design of important structures, additionaldata concerning strength or performance characteristics of the soil underfield conditions will usually be required.1.2 This stand
6、ard 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 This practice offers a se
7、t of instructions for performingone or more specific operations. This practice cannot replaceeducation or experience and should be used in conjunctionwith professional judgment. Not all aspects of this practice maybe applicable in all circumstances. This practice is notintended to represent or repla
8、ce the standard of care by whichthe adequacy of a given professional service must be judged,nor should this practice be applied without consideration of aprojects many unique aspects. The word “Standard” in thetitle of this document means only that the document has beenapproved through the ASTM cons
9、ensus process.2. Referenced Documents2.1 ASTM Standards:2D 420 Guide to Site Characterization for Engineering, De-sign, and Construction PurposesD 421 Practice for Dry Preparation of Soil Samples forParticle-Size Analysis and Determination of Soil Con-stantsD 422 Test Method for Particle-Size Analys
10、is of SoilsD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 1140 Test Methods for Amount of Material in Soils FinerThan the No. 200 (75-m) SieveD 1452 Practice for Soil Investigation and Sampling byAuger BoringsD 1586 Test Method for Penetration Test and Split-BarrelSampling of SoilsD
11、1587 Practice for Thin-Walled Tube Sampling of Soilsfor Geotechnical PurposesD 2217 Practice for Wet Preparation of Soil Samples forParticle-Size Analysis and Determination of Soil Con-stantsD 4318 Test Methods for Liquid Limit, Plastic Limit, andPlasticity Index of Soils2.2 AASHTO Document:3M 145 T
12、he Classification of Soils and Soil Aggregate Mix-tures for Highway Construction Purposes3. Terminology3.1 Definitions of Terms Specific to This Standard:1This standard is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.07 on Identifi
13、cation andClassification of Soils.Current edition approved May 1, 2004. Published May 2004. Originallyapproved in 1973. Last previous edition approved in 1997 as D 3282 93 (1997)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
14、g. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.1Copyright ASTM International, 1
15、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 The following terms are frequently used in this prac-tice. These terms differ slightly from those given in Terminol-ogy D 653, but are used here to maintain consistency withcommon highway usage.3.1.2 bouldersroc
16、k fragments, usually rounded by weath-ering or abrasion, that will be retained on a 3-in. (75-mm)sieve.3.1.3 coarse sandparticles of rock or soil that will pass aNo. 10 (2-mm) sieve and be retained on a No. 40 (425-m)sieve.3.1.4 fine sandparticles of rock or soil that will pass a No.40 (425-m) sieve
17、 and be retained on a No. 200 (75-m) sieve.3.1.5 gravelparticles of rock that will pass a 3-in. (75-mm) sieve and be retained on a No. 10 (2-mm) sieve.3.1.6 silt-clay (combined silt and clay)fine soil and rockparticles that will pass a No. 200 (75-m) sieve.3.1.7 siltyfine-grained material that has a
18、 plasticity indexof 10 or less.3.1.8 clayeyfine-grained material that has a plasticityindex of 11 or more.4. Significance and Use4.1 The practice described classifies soils from any geo-graphic location into groups (including group indexes) basedon the results of prescribed laboratory tests to deter
19、mine theparticle-size characteristics, liquid limit, and plasticity index.4.2 The assigning of a group symbol and group index can beused to aid in the evaluation of the significant properties of thesoil for highway and airfield purposes.4.3 The various groupings of this classification systemcorrelat
20、e in a general way with the engineering behavior ofsoils. Also, in a general way, the engineering behavior of a soilvaries inversely with its group index. Therefore, this practiceprovides a useful first step in any field or laboratory investi-gation for geotechnical engineering purposes.5. Apparatus
21、5.1 Apparatus for Preparation of SamplesSee PracticesD 421 or D 2217.5.2 Apparatus for Particle-Size AnalysisSee Test Meth-ods D 1140 and D 422.5.3 Apparatus for Liquid Limit and Plastic Limit TestsSeeTest Methods D 4318.6. Sampling6.1 Conduct field investigations and sampling in accordancewith one
22、or more of the following procedures:6.1.1 Guide D 420,6.1.2 Practice D 1452,6.1.3 Test Method D 1586, and6.1.4 Practice D 1587.7. Test Sample7.1 Test samples shall represent that portion of the fieldsample finer than the 3-in. (75-mm) sieve and shall be obtainedas follows:7.1.1 Air-dry the field sam
23、ple,7.1.2 Weigh the field sample,7.1.3 Separate the field sample into two fractions on a 3-in.(75-mm) sieve,7.1.4 Weigh the fraction retained on the 3-in. (75-mm)sieve. Compute the percentage of plus 3-in. material in the fieldsample, and note this percentage as auxiliary information, and7.1.5 Thoro
24、ughly mix the fraction passing the 3-in. (75-mm) sieve and select the test samples.NOTE 2If visual examination indicates that no boulder size material ispresent, omit 7.1.3 and 7.1.4.7.2 Prepare the test sample in accordance with PracticesD 421 or D 2217. Determine the percentage of the sample finer
25、than a No. 10 (2-mm) sieve.NOTE 3It is recommended that the method for wet preparation beused for soils containing organic matter or irreversible mineral colloids.8. Testing Procedure8.1 Determine the percentage of the test sample finer than aNo. 200 (75-m) sieve in accordance with Test MethodsD 114
26、0 or D 422.NOTE 4For granular materials, the percentage of the sample finer thana No. 40 (425-m) sieve must also be determined.8.2 Determine the liquid limit and the plasticity index of aportion of the test sample passing a No. 40 (425-m) sieve inaccordance with Test Methods D 4318.9. Classification
27、 Procedure9.1 Using the test data determined in Section 8, classify thesoil into the appropriate group or subgroup, or both, inaccordance with Table 1 or Table 2. Use Fig. 1 to classifysilt-clay materials on the basis of liquid limit and plasticityindex values.NOTE 5All limiting values are shown as
28、whole numbers. If fractionalnumbers appear on test reports, convert to the nearest whole numbers forthe purpose of classification.9.1.1 With the required test data available, proceed from leftto right in Table 1 or Table 2 and the correct classification willbe found by the process of elimination. Th
29、e first group from theleft into which the test data will fit is the correct classification.NOTE 6Classification of materials in the various groups applies onlyto the fraction passing the 3-in. (75-mm) sieve. Therefore, any specifica-tion regarding the use of A-1, A-2, or A-3 materials in constructio
30、n shouldstate whether boulders (retained on 3-in. sieve) are permitted.10. Description of Classification Groups10.1 Granular Materials, containing 35 % or less passingthe No. 200 (75-m) sieve:10.1.1 Group A-1The typical material of this group is awell-graded mixture of stone fragments or gravel, coa
31、rse sand,fine sand, and a nonplastic or feebly-plastic soil binder.However, this group also includes stone fragments, gravel,coarse sand, volcanic cinders, etc., without a soil binder.10.1.1.1 Subgroup A-1-a includes those materials consistingpredominantly of stone fragments or gravel, either with o
32、rwithout a well-graded binder of fine material.10.1.1.2 Subgroup A-1-b includes those materials consistingpredominantly of coarse sand, either with or without a well-graded soil binder.D 3282 93 (2004)e1210.1.2 Group A-3The typical material of this group is finebeach sand or fine desert-blow sand wi
33、thout silty or clay fines,or with a very small amount of nonplastic silt. This group alsoincludes stream-deposited mixtures of poorly-graded fine sandand limited amounts of coarse sand and gravel.10.1.3 Group A-2This group includes a wide variety of“granular” materials which are borderline between t
34、he materi-als falling in Groups A-1 and A-3, and the silt-clay materials ofGroups A-4, A-5, A-6, and A-7. It includes all materialscontaining 35 % or less passing a No. 200 (75-m) sieve whichcannot be classified in Groups A-1 or A-3, due to the finescontent or the plasticity indexes, or both, in exc
35、ess of thelimitations for those groups.10.1.3.1 Subgroups A-2-4 and A-2-5 include various granu-lar materials containing 35 % or less passing a No. 200(75-m) sieve and with a minus No. 40 (425-m) portionhaving the characteristics of Groups A-4 and A-5, respectively.These groups include such material
36、s as gravel and coarse sandwith silt contents or plasticity indexes in excess of thelimitations of Group A-1 and fine sand with nonplastic-siltcontent in excess of the limitations of Group A-3.10.1.3.2 Subgroups A-2-6 and A-2-7 include materials simi-lar to those described under Subgroups A-2-4 and
37、A-2-5,except that the fine portion contains plastic clay having thecharacteristics of the A-6 or A-7 group, respectively.10.2 Silt-Clay Materials, containing more than 35 % pass-ing a No. 200 (75-m) sieve:10.2.1 Group A-4The typical material of this group is anonplastic or moderately plastic silty s
38、oil usually having 75 %or more passing a No. 200 (75-m) sieve. This group alsoincludes mixtures of fine silty soil and up to 64 % of sand andgravel retained on a No. 200 sieve.10.2.2 Group A-5The typical material of this group issimilar to that described under Group A-4, except that it isusually of
39、diatomaceous or micaceous character and may behighly elastic as indicated by the high liquid limit.10.2.3 Group A-6The typical material of this group is aplastic clay soil usually having 75 % or more passing a No. 200(75-m) sieve. This group also includes mixtures of fine clayeysoil and up to 64 % o
40、f sand and gravel retained on a No. 200sieve. Materials of this group usually have a high volumechange between wet and dry states.10.2.4 Group A-7The typical material of this group issimilar to that described under Group A-6, except that it has thehigh liquid limits characteristic of Group A-5 and m
41、ay beelastic as well as subject to high-volume change.TABLE 1 Classification of Soils and Soil-Aggregate MixturesGeneral ClassificationGranular Materials(35 % or less passing No. 200)Silt-Clay Materials(More than 35 % passing No. 200)Group Classification A-1 A-3AA-2 A-4 A-5 A-6 A-7Sieve analysis, %
42、passing:No. 10 (2.00 mm) . . . . . . .No. 40 (425 m) 50 max 51 min . . . . .No. 200 (75 m) 25 max 10 max 35 max 36 min 36 min 36 min 36 minCharacteristics of fraction passing No. 40(425 m):Liquid limitPlasticity index.6 max.N.P.BB40 max10 max41 min10 max40 max11 min 41 min11 minGeneral rating as sub
43、grade Excellent to Good Fair to PoorAThe 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.BSee Table 2 for values.Reprinted with permission of American Association of State Highway and Transportation OfficialsTABLE 2
44、Classification of Soils and Soil-Aggregate MixturesGeneral ClassificationGranular Materials(35 % or less passing No. 200)Silt-Clay Materials(More than 35 % passing No. 200)Group classificationA-1A-3A-2A-4 A-5 A-6A-7A-1-a A-1-b A-2-4 A-2-5 A-2-6 A-2-7A-7-5,A-7-6Sieve analysis, % passing:No. 10 (2.00
45、mm) 50 max . . . . . . . . . .No. 40 (425 m) 30 max 50 max 51 min . . . . . . . .No. 200 (75 m) 15 max 25 max 10 max 35 max 35 max 35 max 35 max 36 min 36 min 36 min 36 minCharacteristics of fraction passingNo. 40 (425 m):Liquid limitPlasticity index.6 max.N.P.40 max10 max41 min10 max40 max11 min41
46、min11 min40 max10 max41 min10 max40 max11 min41 min11 minAUsual types of significant consti-tuent materialsStone Fragments,Gravel and SandFineSandSilty or Clayey Gravel and Sand Silty Soils Clayey SoilsGeneral rating as subgrade Excellent to Good Fair to PoorAPlasticity index of A-7-5 subgroup is eq
47、ual to or less than LL minus 30. Plasticity index of A-7-6 subgroup is greater than LL minus 30 (see Fig. 1).Reprinted with permission of American Association of State Highway and Transportation Officials.D 3282 93 (2004)e1310.2.4.1 Subgroup A-7-5 includes those materials withmoderate plasticity ind
48、exes in relation to the liquid limit andwhich may be highly elastic as well as subject to considerablevolume change.10.2.4.2 Subgroup A-7-6 includes those materials with highplasticity indexes in relation to liquid limit and which aresubject to extremely high volume change.NOTE 7Highly organic soils
49、 (peat or muck) may be classified inGroup A-8. Classification of these materials is based on visual inspectionand is not dependent on the percentage passing the No. 200 (75-m) sieve,liquid limit, or plasticity index. The material is composed primarily ofpartially decayed organic matter, generally has a fibrous texture, a darkbrown or black color, and an odor of decay. These organic materials areunsuitable for use in embankments and subgrades. They are highlycompressible and have low strength.11. Group Index Computation11.1 The classif
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