ASTM C457/C457M-23
(Test Method)Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
SIGNIFICANCE AND USE
5.1 The parameters of the air-void system of hardened concrete determined by the procedures described in this test method are related to the susceptibility of the cement paste portion of the concrete to damage by freezing and thawing. Hence, this test method can be used to develop data to estimate the likelihood of damage due to cyclic freezing and thawing or to explain why it has occurred. The test method can also be used as an adjunct to the development of products or procedures intended to enhance the resistance of concrete to cyclic freezing and thawing.
5.2 Values for parameters of the air-void system can be obtained by any of the procedures described in this test method. The selection of which one of the three methods to be used shall be subject to agreement of the user and provider of the determination
Note 1: Because Procedure C requires darkening the paste and aggregate, its use must occur after other tests if the analyst is also gathering petrographic data in addition to the measurements described in this test method.
5.3 No provision is made for distinguishing among entrapped air voids, entrained air voids, and water voids. Any such distinction is arbitrary, because the various types of voids intergrade in size, shape, and other characteristics. Reports that do make such a distinction typically define entrapped air voids as being larger than 1 mm in at least one dimension being irregular in shape, or both. The honey-combing that is a consequence of the failure to compact the concrete properly is one type of entrapped air void.
5.4 Water voids are cavities that were filled with water at the time of setting of the concrete. They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred. They are most common beneath horizontal reinforcing bars, pieces of coarse aggregate and as channelways along their sides. They occur also immediately below surfaces that were compacted by finish...
SCOPE
1.1 This test method describes procedures for microscopical determinations of the air content of hardened concrete and of the specific surface, void frequency, spacing factor, and paste-air ratio of the air-void system in hardened concrete. Three procedures are described:
1.1.1 Procedure A—Linear-traverse method.
1.1.2 Procedure B—Modified point-count method.
1.1.3 Procedure C—Contrast enhanced method.
1.2 This test method is based on prescribed procedures that are applied to sawed and lapped sections of specimens of concrete from the field or laboratory.
1.3 It is intended to outline the principles of this test method and to establish standards for its adequate performance but not to describe in detail all the possible variations that might be used to accomplish the objectives of this test method.
1.4 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..
1.5 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. For specific hazard statements see Note 9 and Note 12.
1.6 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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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: C457/C457M − 23
Standard Test Method for
Microscopical Determination of Parameters of the Air-Void
1
System in Hardened Concrete
This standard is issued under the fixed designation C457/C457M; 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.
1. Scope* 2. Referenced Documents
2
1.1 This test method describes procedures for microscopical
2.1 ASTM Standards:
determinations of the air content of hardened concrete and of
C42/C42M Test Method for Obtaining and Testing Drilled
the specific surface, void frequency, spacing factor, and paste-
Cores and Sawed Beams of Concrete
air ratio of the air-void system in hardened concrete. Three
C125 Terminology Relating to Concrete and Concrete Ag-
procedures are described:
gregates
1.1.1 Procedure A—Linear-traverse method.
C138/C138M Test Method for Density (Unit Weight), Yield,
1.1.2 Procedure B—Modified point-count method.
and Air Content (Gravimetric) of Concrete
1.1.3 Procedure C—Contrast enhanced method.
C173/C173M Test Method for Air Content of Freshly Mixed
Concrete by the Volumetric Method
1.2 This test method is based on prescribed procedures that
C192/C192M Practice for Making and Curing Concrete Test
are applied to sawed and lapped sections of specimens of
Specimens in the Laboratory
concrete from the field or laboratory.
C231/C231M Test Method for Air Content of Freshly Mixed
1.3 It is intended to outline the principles of this test method
Concrete by the Pressure Method
and to establish standards for its adequate performance but not
C666/C666M Test Method for Resistance of Concrete to
to describe in detail all the possible variations that might be
Rapid Freezing and Thawing
used to accomplish the objectives of this test method.
C670 Practice for Preparing Precision and Bias Statements
1.4 The values stated in either SI units or inch-pound units
for Test Methods for Construction Materials
are to be regarded separately as standard. The values stated in
C672/C672M Test Method for Scaling Resistance of Con-
each system are not necessarily exact equivalents; therefore, to
crete Surfaces Exposed to Deicing Chemicals (Withdrawn
3
ensure conformance with the standard, each system shall be
2021)
used independently of the other, and values from the two
C823/C823M Practice for Examination and Sampling of
systems shall not be combined.
Hardened Concrete in Constructions
1.5 This standard does not purport to address all of the
C856 Practice for Petrographic Examination of Hardened
safety concerns, if any, associated with its use. It is the
Concrete
responsibility of the user of this standard to establish appro-
D92 Test Method for Flash and Fire Points by Cleveland
priate safety, health, and environmental practices and deter-
Open Cup Tester
mine the applicability of regulatory limitations prior to use.
E691 Practice for Conducting an Interlaboratory Study to
For specific hazard statements see Note 9 and Note 12.
Determine the Precision of a Test Method
1.6 This international standard was developed in accor-
4
2.2 American Concrete Institute Standards:
dance with internationally recognized principles on standard-
201.2R Guide to Durable Concrete
ization established in the Decision on Principles for the
211.1 Standard Practice for Selecting Proportions for
Development of International Standards, Guides and Recom-
Normal, Heavyweight, and Mass Concrete
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
1
This test method is under the jurisdiction of ASTM Committee C09 on Standards volume information, refer to the standard’s Document Summary page on
Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee the ASTM website.
3
C09.65 on Petrography. The last approved version of this historical standard is referenced on
Current edition approved Jan. 1, 2023. Published March 2023. Originally www.astm.org.
4
approved in 1960. Last previous edition approved in 2016 as C457/C457M – 16. Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington
DOI: 10.1520/C0457_C0457M-23. Hills, MI 48333-9094, http://www.aci-int.org.
*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
...
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: C457/C457M − 16 C457/C457M − 23
Standard Test Method for
Microscopical Determination of Parameters of the Air-Void
1
System in Hardened Concrete
This standard is issued under the fixed designation C457/C457M; 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.
1. Scope*
1.1 This test method describes procedures for microscopical determinations of the air content of hardened concrete and of the
specific surface, void frequency, spacing factor, and paste-air ratio of the air-void system in hardened concrete. Three procedures
are described:
1.1.1 Procedure A—Linear-traverse method.
1.1.2 Procedure B—Modified point-count method.
1.1.3 Procedure C—Contrast enhanced method.
1.2 This test method is based on prescribed procedures that are applied to sawed and lapped sections of specimens of concrete
from the field or laboratory.
1.3 It is intended to outline the principles of this test method and to establish standards for its adequate performance but not to
describe in detail all the possible variations that might be used to accomplish the objectives of this test method.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not beare not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be
used independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standard.shall not be combined.
1.5 This standard does not purport to address all of the safety concerns concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and healthsafety, health, and environmental practices and
determine the applicability of regulatory limitations prior to use. For specific hazard statements see Note 9 and Note 12.
1.6 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.
1
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.65 on
Petrography.
Current edition approved Dec. 1, 2016Jan. 1, 2023. Published April 2017March 2023. Originally approved in 1960. Last previous edition approved in 20122016 as
C457/C457M – 12. DOI: 10.1520/C0457_C0457M-16.16. DOI: 10.1520/C0457_C0457M-23.
*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
1
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C457/C457M − 23
2. Referenced Documents
2
2.1 ASTM Standards:
C42/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
C125 Terminology Relating to Concrete and Concrete Aggregates
C138/C138M Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete
C173/C173M Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method
C192/C192M Practice for Making and Curing Concrete Test Specimens in the Laboratory
C231/C231M Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C666/C666M Test Method for Resistance of Concrete to Rapid Freezing and Thawing
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
3
C672/C672M Test Method for Scaling Resistance of Concrete Surfaces Exposed to Deicing Chemicals (Withdrawn 2021)
C823/C823M Practice for Examination and Sampling of Hardened Concrete in Constructions
C856 Practice for Petrographic Examination of Hardened Concrete
D92 Test Method for Flash and Fire Points by Cleveland Open Cup Tester
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
4
2.2 American Concrete Institute Standards:
201.2R Guide to Durable Concrete
211.1 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete
3. Terminology
3.1 For definitions of terms used in this test method, refer to Termi
...
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