ASTM D1883-14
(Test Method)Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils
Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils
SIGNIFICANCE AND USE
5.1 This test method is used to evaluate the potential strength of subgrade, subbase, and base course materials, including recycled materials for use in the design of road and airfield pavements. The CBR value obtained in this test forms an integral part of several flexible pavement design methods.
5.2 For applications where the effect of compaction water content on CBR is small, such as cohesionless, coarse-grained materials, or where an allowance is made for the effect of differing compaction water contents in the design procedure, the CBR may be determined at the optimum water content of a specified compaction effort. The specified dry unit weight is normally the minimum percent compaction allowed by the using client’s field compaction specification.
5.3 For applications where the effect of compaction water content on CBR is unknown or where it is desired to account for its effect, the CBR is determined for a range of water contents, usually the range of water content permitted for field compaction by using the client’s protocol or specification for field compaction.
5.4 The criteria for test specimen preparation of self-cementing (and other) materials which gain strength with time must be based on a geotechnical engineering evaluation. As directed by the client, self-cementing materials shall be properly cured until bearing ratios representing long term service conditions can be measured.
Note 1: The quality of the results 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 are generally 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 ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This test method covers the determination of the California Bearing Ratio (CBR) of pavement subgrade, subbase, and base course materials from laboratory compacted specimens. The test method is primarily intended for, but not limited to, evaluating the strength of materials having maximum particle size less than 3/4 in. (19 mm).
1.2 When materials having a maximum particle size greater than 3/4 in. (19 mm) are to be tested, this test method provides for modifying the gradation of the material so that the material used for tests all passes the 3/4-in. (19-mm) sieve while the total gravel (3 in. (75 mm) to plus No. 4 (4.75 mm)) fraction remains the same. While traditionally this method of specimen preparation has been used to avoid the error inherent in testing materials containing large particles in the CBR test apparatus, the modified material may have significantly different strength properties than the original material. However, a large experience database has been developed using this test method for materials for which the gradation has been modified, and satisfactory design methods are in use based on the results of tests using this procedure.
1.3 Past practice has shown that CBR results for those materials having substantial percentages of particles retained on the No. 4 (4.75 mm) sieve are more variable than for finer materials. Consequently, more trials may be required for these materials to establish a reliable CBR.
1.4 This test method provides for the determination of the CBR of a material at optimum water content or a range of water content from a specified compaction test and a specified dry unit weight. The dry unit weight is usually given as a percentage of maximum dry unit weight determined by Test Methods D698 or D1557.
1.5 The client requesting the test may specify the water content or range of water contents and the dry unit weight for which the CBR is desired.
1.6 Unless specified otherwise by the requestin...
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Designation: D1883 − 14
StandardTest Method for
California Bearing Ratio (CBR) of Laboratory-Compacted
1
Soils
This standard is issued under the fixed designation D1883; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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.
1. Scope* 1.5 The client requesting the test may specify the water
content or range of water contents and the dry unit weight for
1.1 This test method covers the determination of the Cali-
which the CBR is desired.
fornia Bearing Ratio (CBR) of pavement subgrade, subbase,
1.6 Unless specified otherwise by the requesting client, or
and base course materials from laboratory compacted speci-
unlessithasbeenshowntohavenoeffectontestresultsforthe
mens.Thetestmethodisprimarilyintendedfor,butnotlimited
material being tested, all specimens shall be soaked prior to
to, evaluating the strength of materials having maximum
3
penetration.
particle size less than ⁄4 in. (19 mm).
1.7 For the determination of CBR of field in-place
1.2 When materials having a maximum particle size greater
3 materials, see Test Method D4429.
than ⁄4 in. (19 mm) are to be tested, this test method provides
for modifying the gradation of the material so that the material
1.8 Units—The values stated in inch-pound units are to be
3
usedfortestsallpassesthe ⁄4-in.(19-mm)sievewhilethetotal
regarded as standard. The SI units given in parentheses are
gravel (3 in. (75 mm) to plus No. 4 (4.75 mm)) fraction
mathematical conversions, which are provided for information
remains the same.While traditionally this method of specimen
purposes only and are not considered standard. Reporting of
preparation has been used to avoid the error inherent in testing
test results in units other than inch-pound units shall not be
materials containing large particles in the CBR test apparatus,
regarded as nonconformance with this test method.
the modified material may have significantly different strength
1.8.1 The gravitational system of inch-pound units is used
properties than the original material. However, a large experi-
when dealing with inch-pound units. In this system, the pound
ence database has been developed using this test method for
(lbf)representsaunitofforce(weight),whiletheunitformass
materials for which the gradation has been modified, and
is slugs. The slug unit is not given, unless dynamic (F = ma)
satisfactory design methods are in use based on the results of
calculations are involved.
tests using this procedure.
1.8.2 The slug unit of mass is almost never used in
commercial practice; that is, density, balances, etc. Therefore,
1.3 Past practice has shown that CBR results for those
the standard unit for mass in this standard is either kilogram
materials having substantial percentages of particles retained
(kg) or gram (g), or both.Also, the equivalent inch-pound unit
on the No. 4 (4.75 mm) sieve are more variable than for finer
(slug) is not given/presented in parentheses.
materials. Consequently, more trials may be required for these
1.8.3 It is common practice in the engineering/construction
materials to establish a reliable CBR.
profession, in the United States, to concurrently use pounds to
1.4 This test method provides for the determination of the
represent both a unit of mass (lbm) and of force (lbf). This
CBR of a material at optimum water content or a range of
implicitly combines two separate systems of units; that is, the
water content from a specified compaction test and a specified
absolutesystemandthegravitationalsystem.Itisscientifically
dry unit weight. The dry unit weight is usually given as a
undesirable to combine the use of two separate sets of
percentage of maximum dry unit weight determined by Test
inchpound units within a single standard. As stated, this
Methods D698 or D1557.
standard includes the gravitational system of inch-pound units
and does not use/present the slug unit for mass. However, the
use of balances or scales recording pounds of mass (lbm) or
3
1 recording density in lbm/ft shall not be regarded as noncon-
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
formance with this standard.
Compressibility of Soils.
1.8.4 The terms density and unit weight are often used
Current edition approved Dec. 1, 2014. Published January 2015. Originally
ϵ2
interchangeably. Density is mass per unit volume whereas unit
approved in 1961. Last previous edition approved in 2007 as D1883–07 . DOI:
10.1520/D1883-14. weight is force per unit volume. In thi
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´2
Designation: D1883 − 07 D1883 − 14
Standard Test Method for
CBR (California Bearing Ratio) California Bearing Ratio
1
(CBR) of Laboratory-Compacted Soils
This standard is issued under the fixed designation D1883; 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.
1
ε NOTE—Editorially corrected units in Section 6.2 in May 2009.
2
ε NOTE—Editorially corrected units in Section 10.3 in July 2009.
1. Scope*
1.1 This test method covers the determination of the CBR (California Bearing Ratio) California Bearing Ratio (CBR) of
pavement subgrade, subbase, and base course materials from laboratory compacted specimens. The test method is primarily
3
intended for (butfor, but not limited to)to, evaluating the strength of materials having maximum particle sizessize less than ⁄4 in.
(19 mm).
3
1.2 When materials having a maximum particle sizessize greater than ⁄4 in. (19 mm) are to be tested, this test method provides
3
for modifying the gradation of the material so that the material used for tests all passes the ⁄4-in. (19-mm) sieve while the total
gravel (+No. 4 to 3 in.) (3 in. (75 mm) to plus No. 4 (4.75 mm)) fraction remains the same. While traditionally this method of
specimen preparation has been used to avoid the error inherent in testing materials containing large particles in the CBR test
apparatus, the modified material may have significantly different strength properties than the original material. However, a large
experience basedatabase has been developed using this test method for materials for which the gradation has been modified, and
satisfactory design methods are in use based on the results of tests using this procedure.
1.3 Past practice has shown that CBR results for those materials having substantial percentages of particles retained on the No.
4 (4.75 mm) sieve are more variable than for finer materials. Consequently, more trials may be required for these materials to
establish a reliable CBR.
1.4 This test method provides for the determination of the CBR of a material at optimum water content or a range of water
content from a specified compaction test and a specified dry unit weight. The dry unit weight is usually given as a percentage of
maximum dry unit weight determined by Test Methods D698 or D1557.
1.5 The agencyclient requesting the test shallmay specify the water content or range of water contentcontents and the dry unit
weight for which the CBR is desired.
1.6 Unless specified otherwise by the requesting agency,client, or unless it has been shown to have no effect on test results for
the material being tested, all specimens shall be soaked prior to penetration.
1.7 For the determination of CBR of field compactedin-place materials, see Test Method D4429.
1.8 Units—The values stated in inch-pound units are to be regarded as the standard. The SI equivalents shown in parentheses
may be approximate. units given in parentheses are mathematical conversions, which are provided for information purposes only
and are not considered standard. Reporting of test results in units other than inch-pound units shall not be regarded as
nonconformance with this test method.
1.8.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf)
represents a unit of force (weight), while the unit for mass is slugs. The slug unit is not given, unless dynamic (F = ma) calculations
are involved.
1.8.2 The slug unit of mass is almost never used in commercial practice; that is, density, balances, etc. Therefore, the standard
unit for mass in this standard is either kilogram (kg) or gram (g), or both. Also, the equivalent inch-pound unit (slug) is not
given/presented in parentheses.
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
Compressibility of Soils.
Current edition approved Nov. 15, 2007Dec. 1, 2014. Published December 2007January 2015. Originally approved in 1961. Last previous edition approved in 20052007
ϵ2
as D1883 – 05.D1883 – 07 . DOI: 10.1520/D1883-07E02.10.1520/D1883-14.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbo
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