ASTM C457-08b

Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete

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 (1). Two procedures are described:
1.1.1 Procedure A, the linear-traverse method (2,3 ).
1.1.2 Procedure B, the modified point-count method (3,4 5,6, ).
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 SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see 8.3 and 10.1.

General Information

• Status: Historical
• Publication Date: 30-Jun-2008
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.65 - Petrography

Relations

• Replaces: ASTM C457-08a - Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
• Effective Date: 01-Jul-2008
• Replaced By: ASTM C457-08c - Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
• Effective Date: 01-Oct-2008
• Referred By: ASTM C856/C856M-20 - Standard Practice for Petrographic Examination of Hardened Concrete
• Effective Date: 01-Jul-2008
• Referred By: ASTM C823/C823M-12(2017) - Standard Practice for Examination and Sampling of Hardened<brk/> Concrete in Constructions
• Effective Date: 01-Jul-2008

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C 457 – 08b
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 C 457; 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.
1. Scope* Yield, and Air Content (Gravimetric) of Concrete
C173/C173M Test Method for Air Content of Freshly
1.1 Thistestmethoddescribesproceduresformicroscopical
Mixed Concrete by the Volumetric Method
determinations of the air content of hardened concrete and of
C231 Test Method for Air Content of Freshly Mixed
the specific surface, void frequency, spacing factor, and paste-
2
Concrete by the Pressure Method
air ratio of the air-void system in hardened concrete (1). Two
C670 Practice for Preparing Precision and Bias Statements
procedures are described:
for Test Methods for Construction Materials
1.1.1 Procedure A, the linear-traverse method (2, 3).
C823 Practice for Examination and Sampling of Hardened
1.1.2 ProcedureB,themodifiedpoint-countmethod(3,4,5,
Concrete in Constructions
6).
C856 Practice for Petrographic Examination of Hardened
1.2 This test method is based on prescribed procedures that
Concrete
are applied to sawed and lapped sections of specimens of
D92 Test Method for Flash and Fire Points by Cleveland
concrete from the field or laboratory.
Open Cup Tester
1.3 Itisintendedtooutlinetheprinciplesofthistestmethod
2.2 American Concrete Institute Standards:
and to establish standards for its adequate performance but not
4
201.2R Guide to Durable Concrete
to describe in detail all the possible variations that might be
211.1 Recommended Practice for Selecting Proportions for
used to accomplish the objectives of this test method.
4
Normal, Heavyweight, and Mass Concrete
1.4 The values stated in SI units are to be regarded as
standard. The values given in parentheses are mathematical
3. Terminology
conversions to inch-pound units that are provided for informa-
3.1 Definitions:
tion only and are not considered standard.
3.1.1 air content (A)—Theproportionofthetotalvolumeof
1.5 This standard does not purport to address all of the
the concrete that is air voids; expressed as percentage by
safety concerns associated with its use. It is the responsibility
volume.
of the user of this standard to establish appropriate safety and
3.1.2 air void—A space enclosed by the cement paste and
health practices and determine the applicability of regulatory
that was filled with air or other gas prior to the setting of the
limitations prior to use. For specific hazard statements see 8.3
paste.
and 10.1.
3.1.2.1 Discussion—This term does not refer to voids of
2. Referenced Documents submicroscopical dimensions, such as the porosity inherent to
3
the hardened-cement paste.Air voids are usually larger than a
2.1 ASTM Standards:
fewmicrometersindiameter.Thetermincludesbothentrapped
C42/C42M Test Method for Obtaining andTesting Drilled
and entrained voids.
Cores and Sawed Beams of Concrete
3.1.3 average chord length( l)—Theaveragelengthofthe
C138/C138M Test Method for Density (Unit Weight),
chords formed by the transection of the voids by the line of
traverse; the unit is a length.
1
3.1.4 paste-air ratio (p/A)—The ratio of the volume of
This test method is under the jurisdiction of ASTM Committee C09 on
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
hardened cement paste to the volume of the air voids in the
C09.65 on Petrography.
concrete.
Current edition approved July 1, 2008. Published August 2008. Originally
3.1.5 paste content (p)—Theproportionofthetotalvolume
approved in 1960. Last previous edition approved in 2008 as C457–08a.
2
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof of the concrete that is hardened cement paste expressed as
this test method.
percentage by volume.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4
Standards volume information, refer to the standard’s Document Summary page on AvailablefromAmericanConcreteInstitute(ACI),P.O.Box9094,Farmington
the ASTM website. 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, United States.
1

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C 457 – 08b
3.1.5.1 Discussion—When this parameter is calculated, it is instances the usual procedure must be changed, and the
the sum of the proportional volume
...

This document is not anASTM standard and is intended only to provide the user of anASTM 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:C 457–08a Designation: C 457 – 08b
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 C 457; 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.
1. Scope*
1.1 This test method describes procedures for microscopical determinations of the air content of hardened concrete and of the
2
specificsurface,voidfrequency,spacingfactor,andpaste-airratiooftheair-voidsysteminhardenedconcrete(1). Twoprocedures
are described:
1.1.1 Procedure A, the linear-traverse method (2, 3).
1.1.2 Procedure B, the modified point-count method (3, 4, 5, 6).
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 SI units are to be regarded as standard. The values given in parentheses are mathematical conversions
to inch-pound units that are provided for information only and are not considered standard.
1.5 This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the
user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations
prior to use. For specific hazard statements see 8.3 and 10.1.
2. Referenced Documents
3
2.1 ASTM Standards:
C42/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
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
C231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C823 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
2.2 American Concrete Institute Standards:
4
201.2R Guide to Durable Concrete
4
211.1 Recommended Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete
3. Terminology
3.1 Definitions:
3.1.1 air content (A)—The proportion of the total volume of the concrete that is air voids; expressed as percentage by volume.
3.1.2 air void—Aspace enclosed by the cement paste and that was filled with air or other gas prior to the setting of the paste.
3.1.2.1 Discussion—This term does not refer to voids of submicroscopical dimensions, such as the porosity inherent to the
hardened-cement paste. Air voids are usually larger than a few micrometers in diameter. The term includes both entrapped and
entrained voids.
1
This test method is under the jurisdiction ofASTM Committee C09 on Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee C09.65 on
Petrography.
Current edition approved MayJuly 1, 2008. Published JuneAugust 2008. Originally approved in 1960. Last previous edition approved in 2008 as C457–08a.
2
The boldface numbers in parentheses refer to the list of references at the end of this test method.
3
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,[e-mail] Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington 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, United States.
1

---------------------- Page: 1 ----------------------
C 457 – 08b
3.1.3 average chord length( l)—Theaveragelengthofthechordsformedbythetransectionofthevoidsbythelineoftraverse;
the unit is a length.
3.1.4 paste-air ratio (p/A)—The ratio of the volume of hardened cement paste to the volume
...