ASTM D4318-17e1
(Test Method)Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
SIGNIFICANCE AND USE
5.1 These test methods are used as an integral part of several engineering classification systems to characterize the fine-grained fractions of soils (see Practices D2487 and D3282) and to specify the fine-grained fraction of construction materials (see Specification D1241). The liquid limit, plastic limit, and plasticity index of soils are also used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, hydraulic conductivity (permeability), compactibility, shrink-swell, and shear strength. (See Section 6, Interferences.)
5.2 The liquid and plastic limits of a soil and its water content can be used to express its relative consistency or liquidity index. In addition, the plasticity index and the percentage finer than 2-μm particle size can be used to determine its activity number.
5.3 These methods are sometimes used to evaluate the weathering characteristics of clay-shale materials. When subjected to repeated wetting and drying cycles, the liquid limits of these materials tend to increase. The amount of increase is considered to be a measure of a shale's susceptibility to weathering.
5.4 The liquid limit of a soil containing substantial amounts of organic matter decreases dramatically when the soil is oven-dried before testing. Comparison of the liquid limit of a sample before and after oven-drying can therefore be used as a qualitative measure of organic matter content of a soil (see Practice D2487).
Note 1: The quality of the result produced by this standard 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, generally, are considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors...
SCOPE
1.1 These test methods cover the determination of the liquid limit, plastic limit, and the plasticity index of soils as defined in Section 3 on Terminology.
1.2 Two procedures for preparing test specimens are provided as follows: Specimen Preparation Procedure 1 (Wet Preparation), as described in 11.1 and Specimen Preparation Procedure 2 (Dry Preparation), as described in 11.2. The specimen preparation procedure to be used shall be specified by the requesting authority. If no specimen preparation procedure is specified, use the wet preparation procedure. (See Section 6, Interferences.)
1.3 Two methods for determining the liquid limit are provided as follows: Liquid Limit Method A (Multipoint Method), as described in Sections 12 and 13, and Liquid Limit Method B (One-Point Method), as described in Sections 14 and 15. The method to be used shall be specified by the requesting authority. If no method is specified, use Method A. (See Section 6, Interferences.)
1.4 The plastic limit test, Method for Plastic Limit, is performed on material prepared for the liquid limit test. When determining the plastic limit, two procedures for rolling portions of the test specimen are provided as follows: Plastic Limit Rolling Procedure 1 (Hand Rolling), and Plastic Limit Rolling Procedure 2 (Using the Rolling Device).
1.5 The liquid limit and plastic limit of soils (along with the shrinkage limit) are often collectively referred to as the Atterberg limits. These limits distinguished the boundaries of the several consistency states of plastic soils.
1.6 The plasticity index, Method for Plasticity Index, is calculated using results from liquid limit and plastic limit testing.
1.7 The methods described herein are performed only on that portion of a soil that passes the 425-μm (No. 40) sieve. Therefore, the relative contribution of this portion of the soil to the properties of the sample as a whole must be considered when usin...
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D4318 − 17
Standard Test Methods for
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Liquid Limit, Plastic Limit, and Plasticity Index of Soils
This standard is issued under the fixed designation D4318; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
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ε NOTE—Editorially updated units of measurement statement in April 2018.
1. Scope* 1.7 The methods described herein are performed only on
that portion of a soil that passes the 425-µm (No. 40) sieve.
1.1 These test methods cover the determination of the liquid
Therefore, the relative contribution of this portion of the soil to
limit, plastic limit, and the plasticity index of soils as defined
the properties of the sample as a whole must be considered
in Section 3 on Terminology.
when using these methods to evaluate the properties of a soil.
1.2 Two procedures for preparing test specimens are pro-
1.8 The values stated in SI units are to be regarded as
vided as follows: Specimen Preparation Procedure 1 (Wet
standard. The values given in parentheses after SI units are
Preparation), as described in 11.1 and Specimen Preparation
provided for information only and are not considered standard.
Procedure 2 (Dry Preparation), as described in 11.2. The
1.8.1 The converted inch-pound units use the gravitational
specimen preparation procedure to be used shall be specified
systemofunits.Inthissystem,thepound(lbf)representsaunit
by the requesting authority. If no specimen preparation proce-
of force (weight), while the unit for mass is slugs. The
dure is specified, use the wet preparation procedure. (See
converted slug unit is not given, unless dynamic (F = ma)
Section 6, Interferences.)
calculations are involved.
1.3 Two methods for determining the liquid limit are pro-
1.8.2 It is common practice in the engineering/construction
vided as follows: Liquid Limit Method A (Multipoint Method),
profession to concurrently use pounds to represent both a unit
as described in Sections 12 and 13, and Liquid Limit Method B
of mass (lbm) and of force (lbf). This implicitly combines two
(One-Point Method), as described in Sections 14 and 15. The
separate systems of units; that is, the absolute system and the
method to be used shall be specified by the requesting
gravitational system. It is scientifically undesirable to combine
authority. If no method is specified, use Method A. (See
the use of two separate sets of inch-pound units within a single
Section 6, Interferences.)
standard. As stated, this standard includes the gravitational
1.4 The plastic limit test, Method for Plastic Limit,is
system of inch-pound units and does not use/present the slug
performed on material prepared for the liquid limit test. When
unit for mass. However, the use of balances or scales recording
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determining the plastic limit, two procedures for rolling por-
pounds of mass (lbm) or recording density in lbm/ft shall not
tionsofthetestspecimenareprovidedasfollows:PlasticLimit
be regarded as nonconformance with this standard.
Rolling Procedure 1 (Hand Rolling), and Plastic Limit Rolling
1.8.3 The “alternative” sieve size designations listed in
Procedure 2 (Using the Rolling Device).
Specification E11 for the 425-µm and 2.00-mm sieves are
given in parentheses following the “standard” designations,
1.5 The liquid limit and plastic limit of soils (along with the
that is, 425-µm (No. 40) and 2.00-mm (No. 10).
shrinkage limit) are often collectively referred to as the
1.8.4 The standard units for the resilience tester covered in
Atterberg limits. These limits distinguished the boundaries of
the several consistency states of plastic soils. Annex A1 are inch-pound, not SI. The SI values given in Fig.
A1.1 are for information only.
1.6 The plasticity index, Method for Plasticity Index,is
calculated using results from liquid limit and plastic limit
1.9 All observed and calculated values shall conform to the
testing. guidelines for significant digits and rounding established in
Practice D6026.
1.9.1 For purposes of comparing a measured or calculated
1 value(s) with specified limits, the measured or calculated
These test methods are under the jurisdiction ofASTM Committee D18 on Soil
and Rock and are the direct responsibility of Subcommittee D18.03 on Texture,
value(s) shall be rounded to the nearest decimal or significant
Plasticity and Density Characteristics of Soils.
digits in the specified limits.
Currentedi
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