Hojas Clasificacion de Suelos Segun AASHTO

8/3/2019 Hojas Clasificacion de Suelos Segun AASHTO

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Standard Practce forclassification of soils and soil-Aggregate Mixtures forHighway Construction purposesr-- vThis standard is issued under the fixed desigmtion D3282; rhe number irnmerliately following the designarion indi'cates the year oftriginal adoption or' in the case of revision, the yar of last revision. A number in parentheses irulicates the year of last reapproval. Aupencript epsilon (e) indicates an editorial change since the last revision or reapproval.7'his standanl ht* been appntedJor use by agencies ofthe l)eparrment ofDefense.

l. ScopeI .l This practice covers a procedure for classifing mineraland orsanomineral soils into seven groups based on liboratorydetermjnation of particle-size disrribuiion, liquid limit, anplasticity index. It may be used when a precise engineeringclassification is required, especially fbr highway constructionpurposes. Evaluation of soils within each group is rnade bymeans of a grozrp index. which is a value calcujated from anenrpirical fomrula,

N-ort I -'Ihe group classification. including the group index, should beuseful in determining the relative quality ofihe sot matea1 for use ineartbrvork struch;res, particularly embankments, subgrades, subbases, andbasss. Horvever fbr the detailed design of important"structures, additionaldata. concerning strengtl or perfonnnce chcteristics of the soil underfield conditions will usually be required.1.2 This standard does not purport to address all of the,salbn, concerns, i/' any, assocatl with its use. It is there:sponsibilty oJ'the user oJ'this standatcl to establish appra_priate safety and health pracfices ant] cletermine the appiica_bili4, r rufuotorv- limitations prior ks use.1.3 This pr-actice ofers a se of instntctiorts for perfonningon,e or more spet:ific operalions. This practice cannot reptaceectucation or experience and should'be usetl in conjunctiont,vth prolbssionaljudgment. Not all aspects of this practice maybe applicable in oll cirt:umstonces. Thi practice is notintended to represent or replctce the stanclardif care by whichthe a(equaq,; of a given p,rofessional .tervice mu* be-judgect,nor shoukl this practice be applied **ithout consideration'of aptoject's mcnv unique aspects. The word ,,Standard" itt the

title oJ'this document nteans only haf the locumenf has beenapproved through the .4 STIz{ consensus process.

2. Referenced Documents2.1 ASTM Standards: 2D 420 Gride to Site Characterization for Engineering, De-sign. and Construction purposesD42l Practice for Dry preparation of Soil Samples lorParticle-Size Analysis and Determination of Soil Con_stantsD 422 Test Method for particle-Size Analysis of SoilsD 653 Ternrinology Relating to Soil. Roci, and C.ontaincdFluidsD I 140 Test N{ethods for Amount of tuIaterial in Soils FinerThan the No. 200 (75-rm) SieveD 1452 Practice for Soil Investigation andAuger Borings Sampling b-v*

,,r.This.srndardisunderrhejurisdictionofASTI\4ContmitteDlgonSoiland1:cx.a.nd rs rhc drrect rtsponsibility olsubcommiitee Dlg,07 on ldmtification andClassification of Soils-Currcrrr ediritr approved Ma_v l, 2004_ published May 2004. Or.igilallyapproved in I 973. Lasr previous e


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d$fp o 3282-sa qzoor1TABLE I Classification of Soils and Sot-Aggregate Mixtures

General Classfication Granular Materials{35 7o or less Passing No. 200)SiltClay Materals(More than 35 % passing No. 200)

Group Classitcation A-1 A-3^ A-6Sieve aalysis, o/o Passing:No. 10 (2.00 mm)No. 40 (425 pm)No. 200 (75 pm)Characterstics of lraction passing No. 40(42s pm):Liquid limitPlasticity ndex

50 max25 max 51 min10 max

N.P

36 min40 max10 max

o rin5 maxBB

36 mn4'1 min10 max

36 min40 max11 min 41 mn11 riin

General rating as subgrade Excellent to GoodA The placng of A-3 before A-2 is necessary in the "leff to rlght elimination process" and does not indcate superiorty of A-3 over A-2B See fable 2 for values.Reprinted with pemssion of American Association of State Hghway and Transportation Officials

Far to Poor

TABLE 2 Glassification of Soils and Soil-Aggregate MixturesGmeral Classificaton Granular Materials(35 % or less passng No. 200) Sillclay Materials(More than 35 % passng No. 200)

A-7Group classification A-3A-l-a A-1-b A-2-4 A-2-5 A-7-5,A-7-6

Sieve analyss, % passing:No- 10 (2.00 mm)No. 40 (425 pm)No. 200 (75 pm)Characterstics of {raction passingNo. 40 (425 !rm):Liquid limitPlasticity ndexUsual types of significnt consti-tuent malerials

50 max30 max 50 max 51 min15 max 25 ma\ 10 max 35 max 35 max 35 max 35 max 36 min 36 min 36 min 36 min40 max 4l mn 40 max 41 min10 max 10 max 11 min 1l mn1"Silty Soils ClaYeY SoilsmaxStone Fragments,Gravel and Sand

N.P.FineSand

40 ma 4l min 40 max 4l min10 max 10 max 1l min f1 mnSilty or Clayey Gravel and SandExcellent to Good Far to PoorA plastcity index of A-7-5 subgroup is equal to or less thn LL minus 30. Plasticity index of A-7-6 subgroup s greater than LL minus 30 (see Fig' 1 )'Reprinled with permission of American Associaton of State Highway and Transportaton Officials.

General rating as subgrade

l0.l .2 Group A-3-The typical material of this group is finebeach sand or fine desert-blow sand lvithout 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 l-2-This group includes a wide variety of"granular" materials which are borderline beh'een the materi-als falling in Groups A-l and A-3, and the silt-clay materials ofCroups A-4, A-5, A-6, and A-7. It includes all materialscontaining 35 Ys or less passing a No. 200 (75-pnl) sieve whichcannot be classified in Cjroups A-1 or A-3, due to the finescontent or the plasticity indexes, or both, in excess of thelimitations for those groups.10.1.3.1 Subgroups A-?-4 andA-2-5 includevarious granu-lar materials containing 35 Ya or less passing a No. 200(75-rm) sieve and with a minus No. A $2-pxrt) portionhaving the characteristics of Groups A-4 and A--1, respectively-These groups include such materials as gravel and coarse sandwith silt contents or plasticity indexes in excess of thelimitations of Group A-l and fine sand rvith nonplastic-siltcontent in excess of the limitations of Group A-3.l0.l .3.2 Subgroups A-2-6 and A-2-7 include materials simi-lar to those described under Subgroups A-24 and 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-Ctay hlaterials, containing mole than 35 -9r pass-ing a No- 200 (75-rm) sieve:10.2.1 Group A-4-The typical material of this group is anonplastic or moderately plastic silty soil usually having 75 9or more passing a No. 200 (75-Um) sieve. This group alsoinctudes mixtures of fine silty soil and up to 64 7o of sand andgravel retained on a No. 200 sieve.10.2.2 Grout A-S--The typical nlaterial of this group issimilar to that described under Group A-4. except that it isusually of diatomaceous or rnicaceous chalacter and may behighly elastic as indicated by the high liquid limit.10.2.3 Grotrp A-6-_The typical material of this group is aplastic clay soil usually having 75 9'o or more passing a No. 200(ZS-r-) sieve. This group also includes nixtures of fine clayc-vsoil and up to 64 -clo of sand and gravel retained on a No. 200sieve. Materials of this group usually have a high volumechange between wet and dry states'102.4 Group A-7-:the typical material of this group issimilar to that described under Group A-6, except that it has thehigh liquitt limits characteristic of Croup A-5 and mav beelastic as rvell as subject to high-volume change.


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,{$J} o s2l2-e3 12oo+'rNorr 8--{roup index values should only be used to compare soilsrvithin the sane group and not br'tw'een goups.12.1.i Materials falling within Groups A-1-a, A-l-b, A-2-4,

A-2-5, and A-3 are satisfactory as subgrade when properlydrained and compacted under noderate thickness of pavementlbase or surface course, or both) of a rype suitable for traffic tobe carried or can be made satisfactory by additions of smallamounts of natural or artificial binders.12.1.2 Materials falling within the "clayey granular"Groups A-2- and A-2-7 and the "silt-clay'' Groups A-4, A-5,A-6, and A-7 r'ill range in quality as subgrade from theapproximate equivalent of the good A-2-4 and A-2-5 subgradesto fair and poor subgrades requiring a layer ofsubbase materialor an increased thickness ofbase course over that required inl2.l.l. in order to rnish adequate support for traffic loads.12.1.3 A minimum of35 %passing a No. 200 (75-pm) sieveis assumed to be critical if plasticity is neglected, but thecritical minimum is only 15 % when afected by plascilyindexes greater than 10.12.1.4 Liquid limits of 40 and above are assumed to becritical.

12..1 .5 Plasticity indexes of I 0 and above are assumed to becritical.12.2 There is no upper limit of group index value obtainedby use of the formula: The adopted critical values of percent-age passing the No. 200 (75-pm) sieve, liquid limit, andplasticity index, are based on an evaluation ol subgrade,subbase, and base-course materials by several highrvay orga-nizations that use the tests involved in this classificationsystem.12.3 Under average conditions ofgood drainage and thor-ough cornpaction, the supporting value of a material assubgrade may be assumed as an inverse ratio to its group index;that is, a group inder ofO indicates a "good" subgrade materialand a group index of 20 or greater indicates a "very poor"subgrade rnaterial.13. Keywords

I 3.1 airfields; Atterberg limits; classification; clay; embank-ments; gradation; gravel; group index; highway constntction;highways; index ranges; sand; silt; soil aggregate mixhrres: soilclassification; soil tests; subgronpsAPPENDIX

(Nonmandatory lnformation)XI. RATIONALE

Xl.l The 1992 edition differs from the previous edition inthat the title was changed to better indicate the use of thestandard.ASTM lntemational takes no positon respecting the valdity of any patent rghts asserted in connecton wth any tem mentonedin this standard. Users of this standard are expressly advised that determination of the validty of any such patent rights, and the riskof infrngment of such rghts, are entirely thir own responsiblity.Ths standard is subject to revision at any tme by the responsible technical commtlee and must be revewed every five years andif not revised, either reapproved orwithdrawn. Your comments are invited elherfor revision of this standard or foraddtional standardsand should be addressed to ASTM lnternational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, whch you may attend. lf you feel that your comments have not receved a fair hearng you shouldmake your views known to the ASTM Commitlee on Slandards, at the address shown below.This standard is copyrighted by ASTM lnternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19424-2959,Unted States. lndividual reprints (single br multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddrss or at 610-832-9585 (phone), 6-10-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website(M.astm.org).


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cair m-rE Jonuqry20ll-Classification of Soil and Soil-Aggregate Mixtures

For Highway Construction PurposesAASHTO M-14s-91 (2008)This practice describes a procedure for classifuing soils into seven groups based on laboratorydetermination of particl-size distribution, liquid limit, and plasticity index- The groupclassification should be useful in determining the relative quality of the soil material for use inembankments, subgrades, and backfills- For detailed design of important structures, additionaldata conceming stiength or performance characteristics of the soil under field conditions willusually be required.Key Elements:l. Determine sieve analysis. Determine sieve analysis using AASHTO T-l I (wash) andAASHTO T-27 (gradation) test procedures (Note l). The 2.00 mm (No. l0) sieve, 425-tm1o. 0) sieve, and 75-tm (No. 200) sieve must be included to determine the particle sizedistribution as a basis for classification.2. Determine the liquid limit. Determine the liquid limit of the material using AASHTO T-89test procedures.3. Determine the plastic limit. Determine the plastic limit and plasticity index of the materialusing AASHTO T-90 test procedures.4. Determine classification of material. Using the test limits shown in Table I of AASHTOM-145, make the classification of the material. If a more detailed classification is desired, afurther subdivision of the groups may be made using Table 2 of AASHTO M-l45 (3.1).With required test data u.nuilubl", proceed from left to right in Table I or Table 2 and thecorrect group will be found by process of elimination (3.2). The first group from the left intowhich all the test data will fit is the correct classification (3.2)-5. Report classification. All limiting test values are shown as whole numbers. If fractionalnu*b"r, appear on test reports, convert to the nearest whole number for purposes ofclassification (3.2).DESCRIPTION OF SOIL CLASSIFICATION GROUPS:Soil Fractions: According to the AASHTO system, soils are divided into two major groups asshown in Table I or Table 2 of AASHTO M-145. These are the granular materials with 35percent or less passing the 75-pm (No. 200) sieve (5.1, Note 2) and the silt-clay materials withmore than 35 percent passing the 75-pm (No. 200) sieve (5.2). Moreover, five soil fractions arerecognized and often sed in word descriptions of a material. These five fractions are defined asfollows:

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Soil M-145 Jonuorv 2ollBoulders and Cobbles - material retained on the 75 mm (3 in.) sieve. They should be excludedfrom the portion of a sample to which the classification is applied, but the percentage of suchmaterial should be recorded (4.1.5).Gravel - materials passing sieve with 75 mm (3 in.) square openings and retained on the 2.0 mmNo. l0) sieve (4.1.1).Coarse Sand - materials40) sieve (4.1.2). the 2.0 mm (No. l0) sieve and retained on the 425-rm (No-Fine Sand -materials passing fhe 425-tm (No. a0) sieve and retained on the 75-pm (No.200)sieve (4.1.3).Combined Silt and Clay - material passing the 75-pm (No. 200) sieve. The word "silty" isapplied to a fine material having a Plasticity Index of 10 or less, and the term "clayey" is appliedto fine material having a PI of more than 10 (4.1.6).GRANULAR MATERIALS:Group A-l: Well-graded mixtures of stone fragments or gravel ranging from coarse to fine witha non-plastic or slightly plastic soil binder (5.1.1). However, this group also includes coarsematerials without soil binder.

Subgroup A-l-a: Materials consisting predominantly of stone fragments or gravel, eitherwith or without a well graded soil binder (5.1.f .1).Subgroup A-l-b: Materials consisting predominantly of coarse sand either with orwithout a well-graded soil binder (5.f .1.2).

Group A-3: Material consisting of sands deficient in coarse material and soil binder. Typical isfine beach sand or fine desert blow sand, without silt or clay fines or with a very small amount ofnon-plastic silt. This group also includes stream deposited mixtures of poorly graded fine sandand limited amounts of coarse sand and gravel (5.1.2). These soils make suitable subgrades forall types of pavements when confined and damp. They are subject to erosion and have beenknown to pump and blow under rigid pavements. (Information: They can be compacted byvibratory, pneumatic-tired, and steel-wheeled rollers but not with a sheepsfoot roller.)Group A-2: This group includes a wide variety of "granular" materials that are borderlinebetween the materials falling in Groups A-l and A-3 and silt-clay materials of Groups A-4, A-5,4-6 and A-7. It includes all materials containing 35 percent or less passing the 75-pm (No. 200)sieve that cannot be classified as A-1 or A-3 (5.1.3).

Subgroups A-2-4 and A-2-5: Include various granular materials containing 35 percent orless passing the 75-pm (No. 200) sieve, and with that portion passing 425-tm (No. 40)sieve having the characteristics of the A-4 and A-5 groups, These groups include suchmaterials as gravel and coarse sand with silt contents or Plasticity Indexes in excess ofNew Mexlco Technicion lroining qnd Cerlilicolion Progrom


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soil M-145 Jonuorv 2ol Ithe limitations of Group A-1, and fine sand with non-plastic silt content in excess of thelimitations of Group A-3 (5.f 3.1).Subgroups A-2-6 and A-2-7: Include materials similar to those describe underSubgroups A-2-4 and A-2-5, except that the fine portion contains plastic clay having thecharacteristics of the A-6 or A-7 group (5.1.3.2).

A-2 soils are given a poorer rating than A-l soils because of inferior binder, poor grading, or acombination of the two. Depending on the character and amount of binder, A-2 soils maybecome soft during wet weather and loose and dusty in dry weather when used as a road surface.If, however, they are protected fiom these extreme changes in moisture content, they may bequite stable. The A-2-4 and A-2-5 soils are satisfactory as base materials when properlycompacted and drained . A-2-6 and A-2-7 soils with low percentages of minus 75-pm (no. 200)sieve material are classified as good bases, whereas these same soils with high percentages ofminus 75-pm (No.200) sieve and PI's of 10 or higher are questionable as a base material.Frequently, the A-2 soils are employed as a cover material for very plastic subgrades.SILT-CLAY MATERIALS:Group A-4: The typical rnaterial of this group is a non-plastic or moderately plastic silty soilusually having 75 percent or more passing the 75 pm (No. 200) sieve. The group includes alsomixtures of fine silty soil and up to 64 percent of sand and gravel retained on the 75-pm (No'200) sieve (5.2.1). These predominantly silty soils are quite common in occurrence. Theirtexture varies from sandy loams to silty and clayey loams. With the proper amount of moisturepresent, they may,perform well as a pavement component. However, they frequently have anaffinity for water and will swell and lose much of their stability unless properly compacted anddrained. Moreover, they are subject to frost heave. These soils do not drain readily and mayabsorb water by capillary action with resulting loss in strength. The silty loams are oftendifficult to compact properly. Careful field control of moisture content and pneumatic tiredrollers are normally required for proper compaction.Group A-5: The typical material of this group is similar to that described under Group A-4,except that it is usually of diatomaceous or micaceous character and may be highly elastic asindicated by the high liquid limit (5.2.2). These soils do not occur as widely as the A-4 soils.They are normally elastic or resilient in both the damp and semi-dry conditions. They aresubject to frost heave, erosion, and loss of stability if not properly drained. Since these soils donot drain readily and may absorb water by capillary action with resulting loss in strength'Careful control of moisture content is normally required for proper compaction.Group A-6: The typical material of this group is plastic clay soil usually having 75 percent ormore passing the 75-pm (No. 200) sieve. The group includes also mixtures of fine clayey soiland up to 64 percent of sand and gravel retained on the 75-pm (No. 200) sieve. Materials of thisgroup usually have high volume change between wet and dry states (5.2.3). These soils are quitecommon in occurrence and are widely used in fills. When moisture content is properlycontrolled, they compact quite readily with either a sheepsfoot or pneumatic tired roller. Theyhave high dry strength but lose much of this strength upon absorbingwater. The 4-6 soils willNew Mexico Technicion lroining ond Cerlilicolion Progrom


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compress when wet and shrink and swell with changes in moisture content. When placed in theshoulders adjacent to the pavement, they tend to shrink away from the pavement edge upondrying and thereby provide an access route to the under side of the pavement for surface water-The A-6 soils do not drain readily and may absorb water by capillary action with resulting loss instrenglh.Group A-7: The typical materials and problems of this group are similar to- those describedunder Group A-6, except that they have the high liquid limits characteristic of the A-5 group andmay be elastic as well as subject to high volume change (5'2'4)'

Subgroup A-7-5: Includes those materials with moderate Plasticity lndexes in relation toI-iquid Limit and which may be highly elastic as well as subject to considerable volumechange (5.2.4.f).Subgroup A-7-6; lncludes those materials with high Plasticity Indexes in relation toLiquid Limit and which are subject to extremely high volume change (5.2-4.2')'Highly organic soils such as peat or muck are not included in this classification- Becauseofinelrmny undesirable properties, theiruse should be avoided, if possible, in all typesof construction.

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Soil M-145 lanuaru ?Ol 1

Classi1 - Classification of Soils and Soil-Aesresate MixturesGeneral Classification Granular Materials(35 Percent or Less Passing 75 mm) Silt-Clay MaterialsThan 35 Percent Passing 75Grouo Classification A-1 A-3. A-2 A-4 A-5 A-6 A-7

Sieve analysig percent pasing2.00 m (No. 10)0.425 mm (No.40)75trm(No.2m) 50 max25 max

51 minl0 max 35 max 36 min 36 min 36 min 36 minCharacteristics of fraction passing 0.425 mm (No. 40)

Liquid limitindex 6 max NP

40 max10 max

4l min10 max

40 max.ll min 41 min11 minGeneral as Excellent to Good Fair to Poor

The placing of A-3 before A-2.is ncesmy in the "left to right elimnation process" and dms not indicate superiority of A-3 over A-2See Table 2 for values.

T Classificationle

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a 2 - Classification of Soils and VlixturesGeneral Classification Granular Materials(35 Percent or Les Passing 75 m) Silt-CIay Materials(More Than 35 Percent Pa$jng 75 mm)Croup Classification

A-1A-3

A-2A-4 A-5 A-6

A-7A-i-a Al-b A-24 A-2-5 A-2-6 A-2-7 A-7-5,A-74

Sieve analysis, percentpassing:2.00 mm (No. 10)0.425 mm (No.40)75 mm lNo.2ff))

50 max30 max15 max

50 max25 max

51 minl0 max 35 mx 35 max 35 nax 35 max 36 min 36 min 36 min 36 minClraracleristics of fractionpassing 0.425 mm (No.40)

Liquid limitindex 6 max NP

40 max'10 ma

4l min10 max

40 max11 min

4l min11 min'

Usual types of significantconstituent materals Stone fragments,gravel and sand FineSand Silty or clayey gravel and sand Silty soils Clayey milsCeneral as Excellent to Grcd Fair to Poor

Plasticity index of A-7-5 subgroup is equal to or les than l-30. Plasticity inda of 4-7-6 subgroup is greater than Ll-30. (Se Figure 2.)

New Mexico Technicion lroining qnd Certficqlion Progrom

Hojas Clasificacion de Suelos Segun AASHTO

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