ASTM D1557-12(2021)

Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft³ (2,700 kN-m/m³))

SIGNIFICANCE AND USE
5.1 Soil placed as engineering fill (embankments, foundation pads, road bases) is compacted to a dense state to obtain satisfactory engineering properties such as shear strength, compressibility, or permeability. In addition, foundation soils are often compacted to improve their engineering properties. Laboratory compaction tests provide the basis for determining the percent compaction and molding water content needed to achieve the required engineering properties, and for controlling construction to assure that the required compaction and water contents are achieved.
Note 3: The degree of soil compaction required to achieve the desired engineering properties is often specified as a percentage of the modified maximum dry unit weight as determined using this test method. If the required degree of compaction is substantially less than the modified maximum dry unit weight using this test method, it may be practicable for testing to be performed using Test Method and to specify the degree of compaction as a percentage of the standard maximum dry unit weight. Since more energy is applied for compaction using this test method, the soil particles are more closely packed than when D698 is used. The general overall result is a higher maximum dry unit weight, lower optimum moisture content, greater shear strength, greater stiffness, lower compressibility, lower air voids, and decreased permeability. However, for highly compacted fine-grained soils, absorption of water may result in swelling, with reduced shear strength and increased compressibility, reducing the benefits of the increased effort used for compaction (2). Use of D698, on the other hand, allows compaction using less effort and generally at a higher optimum moisture content. The compacted soil may be less brittle, more flexible, more permeable, and less subject to effects of swelling and shrinking. In many applications, building or construction codes may direct which test method, D698 or this one, should be used...
SCOPE
1.1 These test methods cover laboratory compaction methods used to determine the relationship between molding water content and dry unit weight of soils (compaction curve) compacted in a 4- or 6-in. (101.6- or 152.4-mm) diameter mold with a 10.00-lbf. (44.48-N) rammer dropped from a height of 18.00 in. (457.2 mm) producing a compactive effort of 56 000 ft-lbf/ft3  (2700 kN-m/m3).
Note 1: The equipment and procedures are the same as proposed by the U.S. Corps of Engineers in 1945. The modified effort test (see 3.1.3) is sometimes referred to as the Modified Proctor Compaction Test.  
1.1.1 Soils and soil-aggregate mixtures are to be regarded as natural occurring fine- or coarse-grained soils, or composites or mixtures of natural soils, or mixtures of natural and processed soils or aggregates such as gravel or crushed rock. Hereafter referred to as either soil or material.  
1.2 These test methods apply only to soils (materials) that have 30 % or less by mass of their particles retained on the 3/4-in. (19.0-mm) sieve and have not been previously compacted in the laboratory; that is, do not reuse compacted soil.  
1.2.1 For relationships between unit weights and molding water contents of soils with 30 % or less by weight of material retained on the 3/4-in. (19.0-mm) sieve to unit weights and molding water contents of the fraction passing the 3/4-in. (19.0-mm) sieve, see Practice D4718/D4718M.  
1.3 Three alternative methods are provided. The method used shall be as indicated in the specification for the material being tested. If no method is specified, the choice should be based on the material gradation.  
1.3.1 Method A:  
1.3.1.1 Mold—4-in. (101.6-mm) diameter.
1.3.1.2 Material—Passing No. 4 (4.75-mm) sieve.
1.3.1.3 Layers—Five.
1.3.1.4 Blows per layer—25.
1.3.1.5 Usage—May be used if 25 % or less by mass of the material is retained on the No. 4 (4.75-mm) sieve. However, if 5 to 25 % by mass of the materi...

General Information

• Status: Published
• Publication Date: 30-Jun-2021
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.03 - Texture, Plasticity and Density Characteristics of Soils

Relations

• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM D4753-24 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D854-23 - Standard Test Methods for Specific Gravity of Soil Solids by the Water Displacement Method
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D2216-19 - Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
• Effective Date: 01-Mar-2019
• Refers: ASTM D2168-10(2018) - Standard Practices for Calibration of Laboratory Mechanical-Rammer Soil Compactors
• Effective Date: 01-Jul-2018
• Refers: ASTM D2487-17e1 - Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• Effective Date: 15-Dec-2017
• Refers: ASTM D2487-17 - Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• Effective Date: 15-Dec-2017
• Refers: ASTM D2488-17 - Standard Practice for Description and Identification of Soils (Visual-Manual Procedures)
• Effective Date: 15-Jul-2017
• Refers: ASTM D4253-16e1 - Standard Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table
• Effective Date: 01-Mar-2016
• Refers: ASTM D4253-16 - Standard Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table
• Effective Date: 01-Mar-2016
• Refers: ASTM D4914/D4914M-16 - Standard Test Methods for Density of Soil and Rock in Place by the Sand Replacement Method in a Test Pit
• Effective Date: 01-Mar-2016
• Refers: ASTM D4753-15 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-May-2015

Overview

ASTM D1557-12(2021), commonly known as the "Modified Proctor Compaction Test," provides standardized laboratory test methods for determining the compaction characteristics of soil using a modified effort of 56,000 ft-lbf/ft³ (2,700 kN-m/m³). Developed by ASTM International, this standard is widely adopted in geotechnical engineering and construction to evaluate the relationship between molding water content and dry unit weight of soils-information critical to ensuring soil is properly compacted for use in fills, embankments, foundations, and road bases.

Proper soil compaction is essential to achieve desired engineering properties such as shear strength, reduced compressibility, and improved permeability. Laboratory compaction test results are often used as a reference for specifying required field compaction levels during construction projects.

Key Topics

• Purpose and Significance

  • Ensures soil used in engineered fills achieves necessary density and water content for optimal performance.
  • Results provide guidelines for controlling construction processes to meet design specifications.

• Methods Covered

  • Three alternative compaction methods (A, B, and C), differentiated by mold size and gradation of soil.
    • Method A: 4-inch mold, material passing No. 4 (4.75-mm) sieve.
    • Method B: 4-inch mold, material passing 3/8-inch (9.5-mm) sieve.
    • Method C: 6-inch mold, material passing 3/4-inch (19.0-mm) sieve.
  • Choice of method depends on material gradation; specific guidance for soils with coarse fractions.

• Procedure Highlights

  • Soil is compacted in five layers, each subjected to a standardized number of blows from a 10-lbf rammer.
  • Compactive effort is significantly greater than in standard methods (e.g., ASTM D698), resulting in higher dry unit weights and lower optimum moisture contents.

• Data Utilization

  • Compaction curves developed from test results are used to determine optimum moisture content and maximum dry density.
  • Degree of compaction in the field is specified as a percentage of the laboratory determined maximum dry unit weight.

• Special Considerations

  • Addresses oversize correction practices for soils containing coarse material.
  • Outlines potential issues (such as particle degradation or gap grading) and references solutions for problematic soils.

Applications

• Construction Quality Control

  • Used to develop and enforce specifications for earthwork compaction in infrastructure and building projects.
  • Helps ensure fills and foundations meet safety and durability requirements.

• Soil Suitability Assessment

  • Evaluates the compactibility of natural and processed soils, soil-aggregate mixtures, gravels, and crushed rock.
  • Guides selection of appropriate compaction techniques based on material characteristics.

• Field Compaction Comparisons

  • Provides a laboratory reference point against which field compaction efforts are measured.

• Code Compliance

  • Often specified by building and construction codes for projects requiring dense, stable, and low-permeability compacted soils.

Related Standards

• ASTM D698 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort
• ASTM D4718/D4718M - Practice for Correction of Unit Weight and Water Content for Soils Containing Oversize Particles
• ASTM D2487 - Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• ASTM D2216 - Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
• ASTM D4253 - Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table

By following ASTM D1557-12(2021), engineers and construction professionals can standardize soil compaction procedures, optimize project outcomes, and confidently meet regulatory and safety requirements for soil-based structural elements. This method is fundamental for controlling the compaction characteristics of soils to achieve the desired engineering properties crucial for long-lasting infrastructure.

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.
Designation: D1557 −12 (Reapproved 2021)
Standard Test Methods for
Laboratory Compaction Characteristics of Soil Using
3 3 1
Modified Effort (56,000 ft-lbf/ft (2,700 kN-m/m ))
This standard is issued under the fixed designation D1557; 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 1.3.1.4 Blows per layer—25.
1.3.1.5 Usage—May be used if 25% or less by mass of the
1.1 These test methods cover laboratory compaction meth-
material is retained on the No. 4 (4.75-mm) sieve. However, if
ods used to determine the relationship between molding water
5 to 25% by mass of the material is retained on the No. 4
content and dry unit weight of soils (compaction curve)
(4.75-mm) sieve, Method A can be used but oversize correc-
compactedina4-or6-in.(101.6-or152.4-mm)diametermold
tions will be required (See 1.4) and there are no advantages to
with a 10.00-lbf. (44.48-N) rammer dropped from a height of
using Method A in this case.
18.00 in. (457.2 mm) producing a compactive effort of 56 000
3 3 1.3.1.6 Other Use—If this gradation requirement cannot be
ft-lbf/ft (2700 kN-m/m ).
met, then Methods B or C may be used.
NOTE 1—The equipment and procedures are the same as proposed by
1.3.2 Method B:
the U.S. Corps of Engineers in 1945. The modified effort test (see 3.1.3)
1.3.2.1 Mold—4-in. (101.6-mm) diameter.
is sometimes referred to as the Modified Proctor Compaction Test.
1.3.2.2 Material—Passing ⁄8-in. (9.5-mm) sieve.
1.1.1 Soilsandsoil-aggregatemixturesaretoberegardedas
1.3.2.3 Layers—Five.
naturaloccurringfine-orcoarse-grainedsoils,orcompositesor
1.3.2.4 Blows per layer—25.
mixtures of natural soils, or mixtures of natural and processed
1.3.2.5 Usage—May be used if 25% or less by mass of the
soils or aggregates such as gravel or crushed rock. Hereafter 3
material is retained on the ⁄8-in. (9.5-mm) sieve. However, if
referred to as either soil or material.
5 to 25% of the material is retained on the ⁄8-in. (9.5-mm)
sieve, Method B can be used but oversize corrections will be
1.2 These test methods apply only to soils (materials) that
have 30% or less by mass of their particles retained on the required (See 1.4). In this case, the only advantages to using
⁄4-in. (19.0-mm) sieve and have not been previously com- Method B rather than Method C are that a smaller amount of
sample is needed and the smaller mold is easier to use.
pacted in the laboratory; that is, do not reuse compacted soil.
1.2.1 For relationships between unit weights and molding 1.3.2.6 Other Usage—If this gradation requirement cannot
be met, then Method C may be used.
water contents of soils with 30% or less by weight of material
retained on the ⁄4-in. (19.0-mm) sieve to unit weights and 1.3.3 Method C:
1.3.3.1 Mold—6-in. (152.4-mm) diameter.
molding water contents of the fraction passing the ⁄4-in.
(19.0-mm) sieve, see Practice D4718/D4718M. 1.3.3.2 Material—Passing ⁄4-in. (19.0-mm) sieve.
1.3.3.3 Layers—Five.
1.3 Three alternative methods are provided. The method
1.3.3.4 Blows per layer—56.
used shall be as indicated in the specification for the material
1.3.3.5 Usage—May be used if 30% or less (see 1.4)by
being tested. If no method is specified, the choice should be
mass of the material is retained on the ⁄4-in. (19.0-mm) sieve.
based on the material gradation.
1.3.4 The6-in.(152.4-mm)diametermoldshallnotbeused
1.3.1 Method A:
with Method A or B.
1.3.1.1 Mold—4-in. (101.6-mm) diameter.
1.3.1.2 Material—Passing No. 4 (4.75-mm) sieve. NOTE 2—Results have been found to vary slightly when a material is
tested at the same compactive effort in different size molds, with the
1.3.1.3 Layers—Five.
smaller mold size typically yielding larger values of unit weight and
density (1).
1.4 If the test specimen contains more than 5% by mass of
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD18onSoil
oversize fraction (coarse fraction) and the material will not be
and Rock and are the direct responsibility of Subcommittee D18.03 on Texture,
Plasticity and Density Characteristics of Soils.
CurrenteditionapprovedJuly1,2021.PublishedJuly2021.Originallyapproved
in 1958. Last previous edition approved in 2012 as D1557–12. DOI: 10.1520/ Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
D1557-12R21. this standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1557 − 12 (2021)
included in the test, corrections must be made to the unit tion. Users should be aware that selling mercury or mercury
weightandmoldingwatercontentofthetestspecimenortothe containing products or both into your state may be prohibited
appropriatefieldin-placeunitweight(ordensity)testspecimen by state law.
using Practice D4718/D4718M.
1.10 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.5 This test method will generally produce a well-defined
ization established in the Decision on Principles for the
maximum dry unit weight for non-free draining soils. If this
Development of International Standards, Guides and Recom-
test method is used for free-draining soils the maximum unit
mendations issued by the World Trade Organization Technical
weight may not be well defined, and can be less than obtained
Barriers to Trade (TBT) Committee.
using Test Methods D4253.
1.6 All observed and calculated values shall conform to the
2. Referenced Documents
guidelines for significant digits and rounding established in 3
2.1 ASTM Standards:
Practice D6026, unless superseded by these test methods.
C127Test Method for Relative Density (Specific Gravity)
1.6.1 For purposes of comparing measured or calculated
and Absorption of Coarse Aggregate
value(s) with specified limits, the measured or calculated
C136/C136MTest Method for Sieve Analysis of Fine and
value(s) shall be rounded to the nearest decimal or significant
Coarse Aggregates
digits in the specified limits.
C670Practice for Preparing Precision and Bias Statements
1.6.2 Theproceduresusedtospecifyhowdataarecollected/ for Test Methods for Construction Materials
recorded or calculated in this standard are regarded as the D653Terminology Relating to Soil, Rock, and Contained
Fluids
industry standard. In addition, they are representative of the
significant digits that generally should be retained. The proce- D698Test Methods for Laboratory Compaction Character-
istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
dures used do not consider material variation, purpose for
obtaining the data, special purpose studies, or any consider- kN-m/m ))
ations for the user’s objectives; it is common practice to D854Test Methods for Specific Gravity of Soil Solids by
increase or reduce significant digits of reported data to be Water Pycnometer
commensuratewiththeseconsiderations.Itisbeyondthescope D2168Practices for Calibration of Laboratory Mechanical-
of these test methods to consider significant digits used in Rammer Soil Compactors
analytical methods for engineering design. D2216Test Methods for Laboratory Determination ofWater
(Moisture) Content of Soil and Rock by Mass
1.7 The values in inch-pound units are to be regarded as the
D2487Practice for Classification of Soils for Engineering
standard. The values stated in SI units are provided for
Purposes (Unified Soil Classification System)
information only, except for units of mass. The units for mass
D2488Practice for Description and Identification of Soils
are given in SI units only, g or kg.
(Visual-Manual Procedures)
1.7.1 It is common practice in the engineering profession to
D3740Practice for Minimum Requirements for Agencies
concurrently use pounds to represent both a unit of mass (lbm)
Engaged in Testing and/or Inspection of Soil and Rock as
and a force (lbf). This implicitly combines two separate
Used in Engineering Design and Construction
systems of units; that is, the absolute system and the gravita-
D4220/D4220MPractices for Preserving and Transporting
tionalsystem.Itisscientificallyundesirabletocombinetheuse
Soil Samples
of two separate sets of inch-pound units within a single
D4253Test Methods for Maximum Index Density and Unit
standard. These test methods have been written using the
Weight of Soils Using a Vibratory Table
gravitationalsystemofunitswhendealingwiththeinch-pound
D4718/D4718MPractice for Correction of Unit Weight and
system.Inthissystem,thepound(lbf)representsaunitofforce
Water Content for Soils Containing Oversize Particles
(weight). However, the use of balances or scales recording
D4753Guide for Evaluating, Selecting, and Specifying Bal-
pounds of mass (lbm) or the recording of density in lbm/ft
ances and Standard Masses for Use in Soil, Rock, and
shall not be regarded as a nonconformance with this standard.
Construction Materials Testing
D4914/D4914MTest Methods for Density of Soil and Rock
1.8 This standard does not purport to address all of the
in Place by the Sand Replacement Method in a Test Pit
safety concerns, if any, associated with its use. It is the
D5030/D5030MTest Methods for Density of In-Place Soil
responsibility of the user of this standard to establish appro-
and Rock Materials by the Water Replacement Method in
priate safety, health, and environmental practices and deter-
a Test Pit
mine the applicability of regulatory limitations prior to use.
D6026Practice for Using Significant Digits and Data Re-
1.9 Warning—Mercury has been designated by EPA and
cords in Geotechnical Data
many state agencies as a hazardous material that can cause
D6913/D6913MTest Methods for Particle-Size Distribution
central nervous system, kidney, and liver damage. Mercury, or
its vapor, may be hazardous to health and corrosive to
materials.Cautionshouldbetakenwhenhandlingmercuryand
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mercury containing products. See the applicable product Ma-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
terial Safety Data Sheet (MSDS) for details and EPA’s website
Standards volume information, refer to the standard’s Document Summary page on
(http://www.epa.gov/mercury/faq.htm) for additional informa- the ASTM website.
D1557 − 12 (2021)
(Gradation) of Soils Using Sieve Analysis are often compacted to improve their engineering properties.
E11Specification forWovenWireTest Sieve Cloth andTest Laboratory compaction tests provide the basis for determining
Sieves the percent compaction and molding water content needed to
E319Practice for the Evaluation of Single-Pan Mechanical achievetherequiredengineeringproperties,andforcontrolling
Balances construction to assure that the required compaction and water
IEEE/ASTM SI 10Standard for Use of the International contents are achieved.
System of Units (SI): The Modern Metric System
NOTE3—Thedegreeofsoilcompactionrequiredtoachievethedesired
engineering properties is often specified as a percentage of the modified
3. Terminology
maximum dry unit weight as determined using this test method. If the
required degree of compaction is substantially less than the modified
3.1 Definitions:
maximumdryunitweightusingthistestmethod,itmaybepracticablefor
3.1.1 See Terminology D653 for general definitions.
testing to be performed using Test Method and to specify the degree of
3.1.2 molding water content, n—the water content of the
compaction as a percentage of the standard maximum dry unit weight.
soil (material) specimen in the mold after it has been reconsti-
Since more energy is applied for compaction using this test method, the
tuted and compacted. soil particles are more closely packed than when D698 is used. The
general overall result is a higher maximum dry unit weight, lower
3.1.3 modified effort—in compaction testing, the term for
optimum moisture content, greater shear strength, greater stiffness, lower
3 3
the56000ft-lbf/ft (2700kN-m/m )compactiveeffortapplied
compressibility,lowerairvoids,anddecreasedpermeability.However,for
by the equipment and methods of this test. highly compacted fine-grained soils, absorption of water may result in
swelling, with reduced shear strength and increased compressibility,
3.1.4 modified maximum dry unit weight, γ (lbf/ft
d,max
reducing the benefits of the increased effort used for compaction (2). Use
(kN/m ))—in compaction testing, the maximum value defined
of D698, on the other hand, allows compaction using less effort and
by the compaction curve for a compaction test using modified
generally at a higher optimum moisture content. The compacted soil may
be less brittle, more flexible, more permeable, and less subject to effects
effort.
of swelling and shrinking. In many applications, building or construction
3.1.5 modified optimum water content, w (%)—in com-
opt
codes may direct which test method, D698 or this one, should be used
paction testing, the water content at which the soil can be
when specifying the comparison of laboratory test results to the degree of
compaction of the in-place soil in the field.
compacted to the maximum dry unit weight using modified
compactive effort.
5.2 Duringdesignofanengineeredfill,testingperformedto
determine shear, consolidation, permeability, or other proper-
3.2 Definitions of Terms Specific to This Standard:
3.2.1 oversize fraction (coarse fraction), P (%)—the por- ties requires test specimens to be prepared by compacting the
C
soil at a prescribed molding water content to obtain a prede-
tion of total specimen not used in performing the compaction
test;itmaybetheportionoftotalspecimenretainedontheNo. termined unit weight. It is common practice to first determine
the optimum water content (w ) and maximum dry unit
4 (4.75-mm) sieve in Method A, ⁄8-in. (9.5-mm) sieve in
opt
Method B, or ⁄4-in. (19.0-mm) sieve in Method C. weight (γ ) by means of a compaction test. Test specimens
dmax
are compacted at a selected molding water content (w), either
3.2.2 test fraction (finer fraction), P (%)—the portion of
F
wet or dry of optimum (w ) or at optimum (w ), and at a
opt opt
the total specimen used in performing the compaction test; it
selected dry unit weight related to a percentage of maximum
may be fraction passing the No. 4 (4.75-mm) sieve in Method
dryunitweight(γ ).Theselectionofmoldingwatercontent
dmax
A, passing the ⁄8-in. (9.5-mm) sieve in Method B, or passing
(w), either wet or dry of optimum (w ) or at optimum (w )
opt opt
the ⁄4-in. (19.0-mm) sieve in Method C.
and the dry unit weight (γ ) may be based on past
dmax
experience, or a range of values may be investigated to
4. Summary of Test Method
determine the necessary percent of compaction.
4.1 A soil at a selected molding water content is placed in
five layers into a mold of given dimensions, with each layer 5.3 Experience indicates that the methods outlined in 5.2 or
the construction control aspects discussed in 5.1 are extremely
compacted by 25 or 56 blows of a 10.00-lbf (44.48-N) rammer
dropped from a distance of 18.00 in. (457.2 mm), subjecting difficult to implement or yield erroneous results when dealing
with some soils. The following subsections describe typical
the soil to a total compactive effort of about 56000 ft-lbf/ft
(2700 kN-m/m ). The resulting dry unit weight is determined. problem soils, the problems encountered when dealing with
such soils and possible solutions for these problems.
The procedure is repeated for a sufficient number of molding
water contents to establish a relationship between the dry unit
5.3.1 Oversize Fraction—Soils containing more than 30%
weight and the molding water content for the soil. This data, oversize fraction (material retained on the ⁄4-in. (19-mm)
when plotted, representacurvilinearrelationshipknownasthe
sieve) are a problem. For such soils, there is no ASTM test
compaction curve. The values of optimum water content and
method to control their compaction and very few laboratories
modified maximum dry unit weight are determined from the
areequippedtodeterminethelaboratorymaximumunitweight
compaction curve.
(density) of such soils (USDI Bureau of Reclamation, Denver,
CO and U.S. Army Corps of Engineers, Vicksburg, MS).
5. Significance and Use
Although Test Methods D4914/D4914M and D5030/D5030M
determine the “field” dry unit weight of such soils, they are
5.1 Soil placed as engineering fill (embankments, founda-
difficult and expensive to perform.
tion pads, road bases) is compacted to a dense state to obtain
satisfactory engineering properties such as shear strength, 5.3.1.1 Onemethodtodesignandcontrolthecompactionof
compressibility, or permeability. In addition, foundation soils such soils is to use a test fill to determine the required degree
D1557 − 12 (2021)
suitability of the equipment and facilities used. Agencies that meet the
ofcompactionandthemethodtoobtainthatcompaction.Then
criteria of Practice D3740 are generally considered capable of competent
use a method specification to control the compaction. Compo-
and objective testing/sampling/inspection/etc. Users of this standard are
nents of a method specification typically contain the type and
cautioned that compliance with Practice D3740 does not in itself assure
size of compaction equipment to be used, the lift thickness,
reliable results. Reliable results depend on many factors; Practice D3740
acceptable range of molding water content, and number of
provides a means of evaluating some of those factors.
passes.
6. Apparatus
NOTE 4—Success in executing the compaction control of an earthwork
project, especially when a method specification is used, is highly 6.1 Mold Assembly—The molds shall be cylindrical in
dependentuponthequalityandexperienceofthecontractorandinspector.
shape, made of rigid metal and be within the capacity and
dimensions indicated in 6.1.1 or 6.1.2 and Fig. 1 and Fig. 2.
5.3.1.2 Another method is to apply the use of density
See also Table 1. The walls of the mold may be solid, split, or
correction factors developed by the USDI Bureau of Reclama-
tapered. The “split” type may consist of two half-round
tion (3,4) and U.S. Corps of Engineers (5). These correction
sections,orasectionofpipesplitalongoneelement,whichcan
factors may be applied for soils containing up to about 50 to
be securely locked together to form a cylinder meeting the
70% oversize fraction. Both agencies use a different term for
requirements of this section. The “tapered” type shall have an
these density correction factors. The USDI Bureau of Recla-
mation uses D ratio (or D – VALUE), while the U.S. Corps of internaldiametertaperthatisuniformandnotmorethan0.200
in./ft(16.7mm/m)ofmoldheight.Eachmoldshallhaveabase
Engineers uses Density Interference Coefficient (I ).
c
plate and an extension collar assembly, both made of rigid
5.3.1.3 The use of the replacement technique (Test Method
metal and constructed so they can be securely attached and
D1557–78, Method D), in which the oversize fraction is
easily detached from the mold. The extension collar assembly
replaced with a finer fraction, is inappropriate to determine the
shall have a height extending above the top of the mold of at
maximum dry unit weight, γ , of soils containing oversize
dmax
least 2.0 in. (51 mm) which may include an upper section that
fractions (5).
flares out to form a funnel, provided there is at least a 0.75-in.
5.3.2 Degradation—Soils containing particles that degrade
(19-mm) straight cylindrical section beneath it. The extension
during compaction are a problem, especially when more
collarshallalignwiththeinsideofthemold.Thebottomofthe
degradation occurs during laboratory compaction than field
base plate and bottom of the centrally recessed area that
compaction, the typical case. Degradation typically occurs
accepts the cylindrical mold shall be planar within 60.005 in.
during the compaction of a granular-residual soil or aggregate.
(60.1 mm).
When degradation occurs, the maximum dry-unit weight in-
6.1.1 Mold, 4 in.—A mold having a 4.000 6 0.016-in.
creases (1) so that the resulting laboratory maximum value is
(101.6 60.4-mm)averageinsidediameter,aheightof4.584 6
not representative of field conditions. Often, in these cases, the
0.018 in. (116.4 6 0.5 mm) and a volume of 0.0333 6 0.0005
maximum dry unit weight is impossible to achieve in the field.
3 3
ft (943.0 6 14.0 cm ).Amold assembly having the minimum
5.3.2.1 Againforsoilssubjecttodegradation,theuseoftest
required features is shown in Fig. 1.
fills and method specifications may help. Use of replacement
6.1.2 Mold, 6 in.—A mold having a 6.000 6 0.026-in.
techniques is not correct.
5.3.3 Gap Graded—Gap-graded soils (soils containing (152.4 60.7-mm)averageinsidediameter,aheightof4.584 6
0.018in.(116.4 60.5mm),andavolumeof0.0750 60.0009
manylargeparticleswithlimitedsmallparticles)areaproblem
3 3
because the compacted soil will have larger voids than usual. ft (2124 6 25 cm ). A mold assembly having the minimum
required features is shown in Fig. 2.
To handle these large voids, standard test methods (laboratory
or field) typically have to be modified using engineering
6.2 Rammer—A rammer, either manually operated as de-
judgement.
scribed further in 6.2.1 or mechanically operated as described
in 6.2.2. The rammer shall fall freely through a distance of
NOTE 5—The quality of the result produced by this standard is
dependent on the competence of the personnel performing it, and the 18.00 6 0.05 in. (457.2 6 1.3 mm) from the surface of the
NOTE 1—See Table 1 for SI equivalents.
FIG. 1 Cylindrical Mold, 4.0-in.
D1557 − 12 (2021)
NOTE 1—See Table 1 for SI equivalents.
FIG. 2 Cylindrical Mold, 6.0-in.
TABLE 1 SI Equivalents for Figs. 1 and 2
shall be ⁄8 in. (9.5 mm). Additional holes or slots may be
in. mm incorporated in the guide sleeve.
0.016 0.41 6.2.2 Mechanical Rammer-Circular Face—The rammer
0.026 0.66
shall operate mechanically in such a manner as to provide
0.032 0.81
uniformandcompletecoverageofthespecimensurface.There
0.028 0.71
⁄2 12.70 shallbe0.10 60.03-in.(2.5 60.8-mm)clearancebetweenthe
2 ⁄8 60.33
rammer and the inside surface of the mold at its smallest
2 ⁄2 63.50
diameter. The mechanical rammer shall meet the
2 ⁄8 66.70
4 101.60 standardization/calibration requirements of Practices D2168.
4 ⁄2 114.30
The mechanical rammer shall be equipped with a positive
4.584 116.43
mechanical means to support the rammer when not in opera-
4 ⁄4 120.60
6 152.40
tion.
6 ⁄2 165.10
6.2.2.1 Mechanical Rammer-Sector Face—The sector face
6 ⁄8 168.30
3 canbeusedwiththe6.0-in.(152.4-mm)mold,asanalternative
6 ⁄4 171.40
8 ⁄4 208.60
to the circular face mechanical rammer described in 6.2.2.The
3 3
ft cm
striking face shall have the shape of a sector of a circle of
⁄30 (0.0333) 943
radius equal to 2.90 6 0.02 in. (73.7 6 0.5 mm) and an area
0.0005 14
⁄13.333 (0.0750) 2,124
about the same as the circular face (see 6.2).The rammer shall
0.0011 31
operate in such a manner that the vertex of the sector is
positioned at the center of the specimen and follow the
compaction pattern given in Fig. 3(b).
6.3 Sample Extruder (optional)—A jack, with frame or
specimen.The weight of the rammer shall be 10.00 6 0.02 lbf
other device adapted for the purpose of extruding compacted
(44.48 6 0.09 N, or mass of 4.5364 6 0.009 kg), except that
specimens from the mold.
the weight of the mechanical rammers may be adjusted as
describedinPracticesD2168(seeNote6).Thestrikingfaceof 6.4 Balance—A Class GP5 balance meeting the require-
the rammer shall be planar and circular, except as noted in
ments of Specification D4753 for a balance of 1-g readability.
6.2.2.1, with a diameter when new of 2.000 6 0.005 in. (50.80 If the water content of the compacted specimens is determined
6 0.13 mm). The rammer shall be replaced if the striking face
using a representative portion of the specimen, rather than the
becomeswornorbelliedtotheextentthatthediameterexceeds whole specimen, and if the representative portion is less than
2.000 6 0.01 in. (50.80 6 0.25 mm).
1000 g, a Class GP2 balance having a 0.1-g readability is
needed in order to comply with Test Methods D2216 require-
NOTE 6—It is a common and acceptable practice to determine the
ments for determining water content to 0.1%.
weight of the rammer using either a kilogram or pound balance and
assume 1 lbf is equivalent to 0.4536 kg, 1 lbf is equivalent to 1 lbm, or 1
NOTE 7—Use of a balance having an equivalent capacity and a
N is equivalent to 0.2248 lbf or 0.1020 kg.
readability of 0.002 lbm as an alternative to a class GP5 balance should
not be regarded as nonconformance to this standard.
6.2.1 Manual Rammer—Therammershallbeequippedwith
a guide sleeve that has sufficient clearance that the free fall of 6.5 Drying Oven—Thermostatically controlled oven, ca-
the rammer shaft and head is not restricted. The guide sleeve pableofmaintainingauniformtemperatureof230 69°F(110
shallhaveatleastfourventholesateachend(eightholestotal) 6 5°C) throughout the drying chamber. These requirements
3 1
located with centers ⁄4 6 ⁄16 in. (19 6 2 mm) from each end typicallyrequiretheuseofaforced-drafttypeoven.Preferably
andspaced90°apart.Theminimumdiameteroftheventholes the oven should be vented outside the building.
D1557 − 12 (2021)
FIG. 3 Rammer Pattern for Compaction in 4-in. (101.6-mm) Mold
6.6 Straightedge—A stiff metal straightedge of any conve- kg, respectively. Greater masses would be required if the
nient length but not less than 10 in. (250 mm).The total length oversize fraction is large (see 10.2 or 10.3) or an additional
of the straightedge shall be machined straight to a tolerance of
molding water content is taken during compaction of each
60.005 in. (60.1 mm). The scraping edge shall be beveled if point (see 10.4.1).
it is thicker than ⁄8 in. (3 mm).
8.2 If gradation data is not available, estimate the percent-
3 3
6.7 Sieves— ⁄4 in. (19.0 mm), ⁄8 in. (9.5 mm), and No. 4
age of material (by mass) retained on the No. 4 (4.75-mm),
(4.75 mm), conforming to the requirements of Specification
3 3
⁄8-in. (9.5-mm), or ⁄4-in. (19.0-mm) sieve as appropriate for
E11.
selecting Method A, B, or C, respectively. If it appears the
6.8 Mixing Tools—Miscellaneous tools such as mixing pan, percentage retained of interest is close to the allowable value
spoon, trowel, spatula, spray device (to add water evenly), and
for a given Method (A, B, or C), then either:
(preferably, but optional) a suitable mechanical device for
8.2.1 Select a Method that allows a higher percentage
thoroughly mixing the subspecimen of soil with increments of
retained (B or C).
water.
8.2.2 Using the sieve size designated for the Method of
interest, process the specimen in accordance with 10.2 or 10.3
7. Standardization/Calibration
herein. This determines the percentage of material retained for
7.1 Perform standardizations before initial use, after repairs
that method. If the percentage retained is acceptable, proceed.
or other occurrences that might affect the test results, at
If the percentage retained is not acceptable, go to Method B or
intervals not exceeding 1000 test specimens, or annually,
C using the next larger sieve size.
whichever occurs first, for the following apparatus:
8.2.3 Determine percentage retained values using a repre-
7.1.1 Balance—Evaluate in accordance with Specification
sentative portion from the total sample, and performing a
D4753 or Practice E319.
simplified or complete gradation analysis using the sieve(s) of
7.1.2 Molds—Determine the volume as described in Annex
interest and Test Method D6913/D6913M or C136/C136M.It
A1.
isonlynecessarytocalculatetheretainedpercentage(s)forthe
7.1.3 Manual Rammer—Verify the free fall distance, ram-
sieve or sieves for which information is desired.
merweight,andrammerfaceareinaccordancewith6.2.Verify
the guide sleeve requirements in accordance with 6.2.1.
9. Preparation of Apparatus
7.1.4 Mechanical Rammer—Verify and adjust if necessary
that the mechanical rammer in accordance with Practices
9.1 Select the proper compaction mold(s), collar, and base
D2168. In addition, the clearance between the rammer and the
plate in accordance with the Method (A, B, or C) being used.
inside surface of the mold shall be verified in accordance with
Check that the volume of the mold is known and whether the
6.2.2.
volume was determined with or without the base plate. Also,
check that the mold is free of nicks or dents, and that the mold
8. Test Specimen
will fit together properly with the collar and base plate.
8.1 The minimum test specimen (test fraction) mass for
9.2 Check that the manual or mechanical rammer assembly
MethodsAandBisabout16kg,andforMethodCisabout29
kg of dry soil. Therefore, the field sample (see Practices is in good working condition and that parts are not loose or
worn. Make any necessary adjustments or repairs. If adjust-
D4220/D4220M for practices of preserving and transporting
soilsamples)shouldhaveamoistmassofatleast23kgand45 mentsorrepairsaremade,therammermustberestandardized.
D1557 − 12 (2021)
10. Procedure point).Selectabout2.3kgwhenusingMethodAorB,orabout
5.9 kg for Method C. Test Method D6913/D6913M section on
10.1 Soils:
Specimen and Annex A2 give additional details on obtaining
10.1.1 Donotreusesoilthathasbeenpreviouslycompacted
representative soil using this procedure and the reason it is the
inthelaboratory.Thereuseofpreviouslycompactedsoilyields
preferred method. To obtain the subspecimen’s molding water
a significantly greater maximum dry unit weight (1).
contents selected in 10.2.1, add or remove the required
10.1.2 When using this test method for soils containing
amountsofwaterasfollows:Toaddwater,sprayitintothesoil
hydrated halloysite, or in which past experience indicates that
during mixing; to remove water, allow the soil to dry in air at
results will be altered by air-drying, use the moist preparation
ambient temperature or in a drying apparatus such that the
method (see Section 10.2). In referee testing, each laboratory
temperature of the sample does not exceed 140°F (60°C). Mix
has to use the same method of preparation, either moist
the soil frequently during drying to facilitate an even water
(preferred) or air-dried.
content distribution. Thoroughly mix each subspecimen to
10.1.3 Prepare the soil specimens for testing in accordance
facilitate even distribution of water throughout and then place
with 10.2 (preferred) or with 10.3.
in a separate covered container to stand (cure) in accordance
10.2 Moist Preparation Method (preferred)—Without pre-
withTable2priortocompaction.Forselectingastandingtime,
viously drying the sample/specimen, process it over a No. 4
the soil may be classified using Practice D2487, Practice
3 3
(4.75-mm), ⁄8-in. (9.5-mm), or ⁄4-in. (19.0-mm) sieve, de-
D2488ordataonothersamplesfromthesamematerialsource.
pending on the Method (A, B, or C) being used or required as
For referee testing, classification shall be by Practice D2487.
covered in 8.2. For additional processing details, see Test
10.3 Dry Preparation Method—If the sample/specimen is
Method D
...