ASTM C131/C131M-20

Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

SIGNIFICANCE AND USE
5.1 This test has been widely used as an indicator of the relative quality or competence of various sources of aggregate having similar mineral compositions. The results do not automatically permit valid comparisons to be made between sources distinctly different in origin, composition, or structure. Assign specification limits with extreme care in consideration of available aggregate types and their performance history in specific end uses. The percent loss determined by this test method has no known consistent relationship to the percent loss for the same material when tested by Test Method C535.
SCOPE
1.1 This test method covers a procedure for testing of coarse aggregates with a maximum size smaller than 37.5 mm ([11/2 in.] for resistance to degradation using the Los Angeles testing machine (Note 1).  
Note 1: A procedure for testing coarse aggregate larger than 19.0 mm [3/4 in.] is covered in Test Method C535. Thus coarse aggregates with a maximum size between 19 mm [3/4 in.] and 37.5 mm [11/2 in.] may be tested by Test Method C535 or Test Method C131/C131M.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
Note 2: Sieve size is identified by its standard designation in Specification E11. The Alternative designation given in parentheses is for information only and does not represent a different standard sieve size.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 14-Feb-2020
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.20 - Aggregates

Relations

• Replaces: ASTM C131/C131M-14 - Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
• Effective Date: 15-Feb-2020
• Refers: ASTM A6/A6M-24 - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
• Effective Date: 01-Mar-2024
• 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 C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM A6/A6M-23 - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
• Effective Date: 01-Nov-2023
• Refers: ASTM C125-19a - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 15-Dec-2019
• Refers: ASTM C125-19 - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Jan-2019
• Refers: ASTM C125-18b - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Oct-2018
• Refers: ASTM C125-18a - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Jul-2018
• Refers: ASTM C125-18 - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Jan-2018
• Refers: ASTM A6/A6M-17a - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
• Effective Date: 01-Nov-2017
• Refers: ASTM C125-16 - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 15-Dec-2016
• Refers: ASTM A6/A6M-16a - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
• Effective Date: 15-Nov-2016
• Refers: ASTM C535-16 - Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
• Effective Date: 15-Jun-2016
• Refers: ASTM A6/A6M-16 - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
• Effective Date: 01-May-2016

Overview

ASTM C131/C131M-20 is the internationally recognized standard test method for determining resistance to degradation of small-size coarse aggregate by abrasion and impact in the Los Angeles Machine. This standard is maintained by ASTM International and is widely used in the construction and materials testing industry to assess the quality and durability of coarse aggregate, especially for aggregates smaller than 37.5 mm (1½ in.) in maximum size. It provides an essential measure of aggregate durability, supporting the selection of suitable materials for concrete, road base, and other construction applications where aggregate performance is critical.

Key Topics

• Test Method Scope: ASTM C131/C131M-20 applies specifically to small-size coarse aggregates, defining procedures for abrasion and impact testing using a rotating drum (Los Angeles Machine) and steel spheres.
• Measurement Units: Both SI and inch-pound units are covered. The values in each system are treated as standard and must not be combined for compliance.
• Apparatus and Materials:
  • Los Angeles Machine conforming to precise specifications
  • Standard sieves as per ASTM E11
  • Steel spheres/ball bearings for abrasion
  • Oven for sample drying
  • Accurate balance or scale
• Procedure: A graded sample of aggregate is weighed, placed with steel spheres in the Los Angeles Machine, and rotated for a specified number of revolutions. The resulting loss, expressed as a percentage, indicates resistance to abrasion and impact.
• Significance: This test serves as an indicator of relative aggregate quality within similar mineralogical materials. Results may guide specification limits but should not be used to compare aggregates of different origins or types directly.

Applications

The ASTM C131/C131M-20 test method is widely applied in:

• Quality Control: Used by aggregate producers, suppliers, and certifying agencies to ensure products meet durability requirements.
• Concrete Mix Design: Assists engineers and designers in selecting aggregates with suitable resistance to degradation for reliably durable concrete structures.
• Road Construction: Essential for evaluating aggregates used in pavement bases and surfacing, where impact and abrasion from vehicle traffic are significant concerns.
• Material Specification: Enables contractors and specifiers to compare different aggregate sources of similar composition based on a standardized test.
• Performance Evaluation: Helps verify compliance with project specifications and industry standards for aggregate durability.

Note: The percent loss measured by ASTM C131/C131M-20 does not have a direct, consistent correlation to the percent loss from larger aggregates tested under ASTM C535. Careful consideration is required when setting specification thresholds, and historical performance data should guide their use.

Related Standards

Other ASTM standards referenced or closely associated with this test method include:

• ASTM C535: Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
• ASTM C125: Terminology Relating to Concrete and Concrete Aggregates
• ASTM C136: Test Method for Sieve Analysis of Fine and Coarse Aggregates
• ASTM C702: Practice for Reducing Samples of Aggregate to Testing Size
• ASTM D75: Practice for Sampling Aggregates
• ASTM E11: Specification for Woven Wire Test Sieve Cloth and Test Sieves

By following ASTM C131/C131M-20, organizations ensure consistent, reliable measurement of coarse aggregate resistance to abrasion and impact, supporting better materials selection and performance across a range of construction and civil engineering projects.

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: C131/C131M − 20
Standard Test Method for
Resistance to Degradation of Small-Size Coarse Aggregate
by Abrasion and Impact in the Los Angeles Machine
This standard is issued under the fixed designation C131/C131M; 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. Scope* 2. Referenced Documents
2.1 ASTM Standards:
1.1 Thistestmethodcoversaprocedurefortestingofcoarse
A6/A6M Specification for General Requirements for Rolled
aggregates with a maximum size smaller than 37.5 mm ([1 ⁄2
Structural Steel Bars, Plates, Shapes, and Sheet Piling
in.] for resistance to degradation using the LosAngeles testing
C125 Terminology Relating to Concrete and Concrete Ag-
machine (Note 1).
gregates
NOTE 1—Aprocedure for testing coarse aggregate larger than 19.0 mm
C136 Test Method for Sieve Analysis of Fine and Coarse
[ ⁄4 in.] is covered in Test Method C535. Thus coarse aggregates with a
Aggregates
3 1
maximum size between 19 mm [ ⁄4 in.] and 37.5 mm [1 ⁄2 in.] may be
C535 Test Method for Resistance to Degradation of Large-
tested by Test Method C535 or Test Method C131/C131M.
Size CoarseAggregate byAbrasion and Impact in the Los
1.2 The values stated in either SI units or inch-pound units
Angeles Machine
are to be regarded separately as standard. The values stated in
C670 Practice for Preparing Precision and Bias Statements
each system are not necessarily exact equivalents; therefore, to
for Test Methods for Construction Materials
ensure conformance with the standard, each system shall be
C702 PracticeforReducingSamplesofAggregatetoTesting
used independently of the other, and values from the two
Size
systems shall not be combined.
D75 Practice for Sampling Aggregates
E11 Specification for Woven Wire Test Sieve Cloth and Test
NOTE 2—Sieve size is identified by its standard designation in Speci-
Sieves
fication E11. The Alternative designation given in parentheses is for
information only and does not represent a different standard sieve size.
3. Terminology
1.3 This standard does not purport to address all of the
3.1 Definitions—For definitions of terms used in this test
safety concerns, if any, associated with its use. It is the
method, refer to Terminology C125.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
4.1 This test is a measure of degradation of mineral aggre-
1.4 This international standard was developed in accor-
gates of standard gradings resulting from a combination of
dance with internationally recognized principles on standard-
actions including abrasion or attrition, impact, and grinding in
ization established in the Decision on Principles for the
a rotating steel drum containing a specified number of steel
Development of International Standards, Guides and Recom-
spheres, the number depending upon the grading of the test
mendations issued by the World Trade Organization Technical
sample. As the drum rotates, a shelf plate picks up the sample
Barriers to Trade (TBT) Committee.
and the steel spheres, carrying them around until they are
dropped to the opposite side of the drum, creating an impact-
crushing effect. The contents then roll within the drum with an
This test method is under the jurisdiction of ASTM Committee C09 on
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
C09.20 on Aggregates. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 15, 2020. Published April 2020. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1937. Last previous edition approved in 2014 as C131/C131M – 14. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C0131_C0131M-20. the ASTM website.
*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
C131/C131M − 20
abrading and grinding action until the shelf plate picks up the Fig. 1, shall be used. The machine shall consist of a hollow
sample and the steel spheres, and the cycle is repeated. After steel cylinder, with a wall thickness of at least 12 mm [ ⁄2 in.]
the prescribed number of revolutions, the contents are removed
(Note 3) closed at both ends, conforming to the dimensions
from the drum and the aggregate portion is sieved to measure
shown in Fig. 1, having an inside diameter of 710 65mm[28
the degradation as percent loss.
6 0.2 in.], and an inside length of 510 65mm[20 6 0.2 in.].
The interior surface of the cylinder shall be free from protru-
5. Significance and Use
sions disrupting the path of the sample and steel spheres except
5.1 This test has been widely used as an indicator of the
fortheshelfdescribedbelow.Thecylindershallbemountedon
relative quality or competence of various sources of aggregate
stub shafts attached to the ends of the cylinder but not entering
having similar mineral compositions. The results do not
it, and shall be mounted in such a manner that it rotates with
automatically permit valid comparisons to be made between
the axis in a horizontal position within a tolerance in slope of
sources distinctly different in origin, composition, or structure.
1 in 100. An opening in the cylinder shall be provided for the
Assign specification limits with extreme care in consideration
introduction of the test sample. A suitable, dust-tight cover
of available aggregate types and their performance history in
shall be provided for the opening with means for bolting the
specific end uses. The percent loss determined by this test
cover in place. The cover shall be so designed as to maintain
method has no known consistent relationship to the percent
the cylindrical contour of the interior surface unless the shelf is
loss for the same material when tested by Test Method C535.
so located that the steel spheres and sample shall not impact on
6. Apparatus
or near the door opening and the opening cover during the test.
A removable steel shelf extending the full length of the
6.1 Los Angeles Machine—A Los Angeles machine, con-
forming in all essential characteristics to the design shown in cylinder and projecting inward 90 6 2 mm [3.5 6 0.1 in.] shall
FIG. 1 Los Angeles Testing Machine
C131/C131M − 20
be mounted on the interior cylindrical surface of the cylinder,
Number of Mass of
Grading Spheres Charge, g
in such a way that a plane centered between the large faces
A 12 5000 ± 25
coincides with an axial plane. The shelf shall be of such
B 11 4580 ± 25
thickness and so mounted, by bolts or other suitable means, as
C 8 3330 ± 20
D 6 2500 ± 15
to be firm and rigid. The position of the shelf (Note 4) shall be
such that the sample and the steel spheres shall not impact on NOTE 6—The total mass specified requires an average mass of each
steel sphere or ball bearing of 416 g. Steel spheres or ball bearings 46.0
orneartheopeninganditscover,andthatthedistancefromthe
13 7
mm [1 ⁄16 in.] and 47.6 mm [1 ⁄8 in.] in diameter, having a mass of
shelf to the opening, measured along the outside circumference
approximately 400 and 440 g each, respectively, are readily available.
ofthecylinderinthedirectionofrotation,shallbenotlessthan 27
Steel spheres or ball bearings 46.8 mm [1 ⁄32 in.] in diameter having a
1270 mm [50 in.]. Inspect the shelf periodically to determine
mass of approximately 420 g may also be obtainable. The charge may
consist of a mixture of these sizes conforming to the mass tolerances of
that it is not bent either lengthwise or from its normal radial
6.5 and 6.5.1.
position with respect to the cylinder. If either condition is
found, repair or replace the shelf before further tests are
7. Sampling
conducted.
7.1 Obtain the field sample in accordance with Practice
NOTE 3—Tolerances for wall thickness are given in Specification
D75, and reduce the field sample to adequate sample size in
A6/A6M.
accordance with Practice C702.
NOTE
...

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.
Designation: C131/C131M − 14 C131/C131M − 20
Standard Test Method for
Resistance to Degradation of Small-Size Coarse Aggregate
by Abrasion and Impact in the Los Angeles Machine
This standard is issued under the fixed designation C131/C131M; 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. Scope*
1.1 This test method covers a procedure for testing of coarse aggregates with a maximum size smaller than 37.5 mm ([1 ⁄2 in.]
for resistance to degradation using the Los Angeles testing machine (Note 1).
NOTE 1—A procedure for testing coarse aggregate larger than 19.0 mm [ ⁄4 in.] is covered in Test Method C535. Thus coarse aggregates with a
3 1
maximum size between 19 mm [ ⁄4 in.] and 37.5 mm [1 ⁄2 in.] may be tested by Test Method C535 or Test Method C131/C131M.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
NOTE 2—Sieve size is identified by its standard designation in Specification E11. The Alternative designation given in parentheses is for information
only and does not represent a different standard sieve size.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
A6/A6M Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
C125 Terminology Relating to Concrete and Concrete Aggregates
C136 Test Method for Sieve Analysis of Fine and Coarse Aggregates
C535 Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles
Machine
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C702 Practice for Reducing Samples of Aggregate to Testing Size
D75 Practice for Sampling Aggregates
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminology C125.
4. Summary of Test Method
4.1 This test is a measure of degradation of mineral aggregates of standard gradings resulting from a combination of actions
including abrasion or attrition, impact, and grinding in a rotating steel drum containing a specified number of steel spheres, the
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.20 on
Normal Weight Aggregates.
Current edition approved July 1, 2014Feb. 15, 2020. Published July 2014April 2020. Originally approved in 1937. Last previous edition approved in 20062014 as
C131C131/C131M – 14. – 06. DOI: 10.1520/C0131_C0131M-14.10.1520/C0131_C0131M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
C131/C131M − 20
number depending upon the grading of the test sample. As the drum rotates, a shelf plate picks up the sample and the steel spheres,
carrying them around until they are dropped to the opposite side of the drum, creating an impact-crushing effect. The contents then
roll within the drum with an abrading and grinding action until the shelf plate picks up the sample and the steel spheres, and the
cycle is repeated. After the prescribed number of revolutions, the contents are removed from the drum and the aggregate portion
is sieved to measure the degradation as percent loss.
5. Significance and Use
5.1 This test has been widely used as an indicator of the relative quality or competence of various sources of aggregate having
similar mineral compositions. The results do not automatically permit valid comparisons to be made between sources distinctly
different in origin, composition, or structure. Assign specification limits with extreme care in consideration of available aggregate
types and their performance history in specific end uses. The percent loss determined by this test method has no known consistent
relationship to the percent loss for the same material when tested by Test Method C535.
6. Apparatus
6.1 Los Angeles Machine—A Los AnglesAngeles machine, conforming in all essential characteristics to the design shown in
Fig. 1, shall be used. The machine shall consist of a hollow steel cylinder, with a wall thickness of at least 12 mm [ ⁄2 in.] (Note
3) closed at both ends, conforming to the dimensions shown in Fig. 1, having an inside diameter of 711710 6 5 mm [28 6 0.2
in.], and an inside length of 508510 6 5 mm [20 6 0.2 in.]. The interior surface of the cylinder shall be free from protrusions
disrupting the path of the sample and steel spheres except for the shelf described below. The cylinder shall be mounted on stub
shafts attached to the ends of the cylinder but not entering it, and shall be mounted in such a manner that it rotates with the axis
FIG. 1 Los Angeles Testing Machine
C131/C131M − 20
in a horizontal position within a tolerance in slope of 1 in 100. An opening in the cylinder shall be provided for the introduction
of the test sample. A suitable, dust-tight cover shall be provided for the opening with means for bolting the cover in place. The
cover shall be so designed as to maintain the cylindrical contour of the interior surface unless the shelf is so located that the steel
spheres and sample shall not impact on or near the door opening and the opening cover during the test. A removable steel shelf
extending the full length of the cylinder and projecting inward 8990 6 2 mm [3.5 6 0.1 in.] shall be mounted on the interior
cylindrical surface of the cylinder, in such a way that a plane centered between the large faces coincides with an axial plane. The
shelf shall be of such thickness and so mounted, by bolts or other suitable means, as to be firm and rigid. The position of the shelf
(Note 4) shall be such that the sample and the steel spheres shall not impact on or near the opening and its cover, and that the
distance from the shelf to the opening, measured along the outside circumference of the cylinder in the direction of rotation, shall
be not less than 1270 mm [50 in.]. Inspect the shelf periodically to determine that it is not bent either lengthwise or from its normal
radial position with respect to the cylinder. If either condition is found, repair or replace the shelf before further tests are conducted.
NOTE 3—Tolerances for wall thickness are given in Specification A6/A6M.
NOTE 4—The use of a shelf of wear-resistant steel, rectangular in cross section and mounted independently of the cover, is preferred. However, a shelf
consisting of a section of rolled angle, properly mounted on the inside of the cover plate, may be used provided the direction of rotation is such that the
charge will be caught on the outside face of the angle.
6.1.1 The machine shall be so driven and so counterbalanced as to maintain a rotation speed of 30 to 33 rpm (Note 5). If an
angle is used as the shelf, the direction of rotation shall be such that the charge is caught on the outside surface of the angle.
NOTE 5—Back-lash or slip in the driving mechanism is very likely to furnish test results which are not duplicated by other Los Angeles machines
producing constant peripheral speed.
6.2 Sieves, conforming to Specification E11.
6.3 Balance—A balance or scale accurate within 0.1 % of test load over the range required for this test.
6.4 Oven—An oven of appropriate size capable of maintaining a uniform temperature of 110 6 5°C [230 6 10°F].
6.5 Charge—The charge shall c
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