ASTM C457-06

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 (). Two procedures are described:
1.1.1 Procedure A, the linear-traverse method (, ).
1.1.2 Procedure B, the modified point-count 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 SI units are to be regarded as the standard. The values in parentheses are provided for information purposes only.
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 and .

General Information

• Status: Historical
• Publication Date: 31-Dec-2005
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.65 - Petrography

Relations

• Replaces: ASTM C457-98 - Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
• Effective Date: 01-Jan-2006
• Replaced By: ASTM C457-08 - Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
• Effective Date: 01-Jan-2008
• Referred By: ASTM C856/C856M-20 - Standard Practice for Petrographic Examination of Hardened Concrete
• Effective Date: 01-Jan-2006
• Referred By: ASTM C823/C823M-12(2017) - Standard Practice for Examination and Sampling of Hardened<brk/> Concrete in Constructions
• Effective Date: 01-Jan-2006

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 – 06
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope C173/C173M Test Method for Air Content of Freshly
Mixed Concrete by the Volumetric Method
1.1 Thistestmethoddescribesproceduresformicroscopical
C231 Test Method for Air Content of Freshly Mixed
determinations of the air content of hardened concrete and of
Concrete by the Pressure Method
the specific surface, void frequency, spacing factor, and paste-
2
C670 Practice for Preparing Precision and Bias Statements
air ratio of the air-void system in hardened concrete (1). Two
for Test Methods for Construction Materials
procedures are described:
C823 Practice for Examination and Sampling of Hardened
1.1.1 Procedure A, the linear-traverse method (2, 3).
Concrete in Constructions
1.1.2 ProcedureB,themodifiedpoint-countmethod(3,4,5,
C856 Practice for Petrographic Examination of Hardened
6).
Concrete
1.2 This test method is based on prescribed procedures that
D92 Test Method for Flash and Fire Points by Cleveland
are applied to sawed and lapped sections of specimens of
Open Cup Tester
concrete from the field or laboratory.
2.2 American Concrete Institute Standards:
1.3 Itisintendedtooutlinetheprinciplesofthistestmethod
4
201.2R Guide to Durable Concrete
and to establish standards for its adequate performance but not
211.1 Recommended Practice for Selecting Proportions for
to describe in detail all the possible variations that might be
4
Normal, Heavyweight, and Mass Concrete
used to accomplish the objectives of this test method.
1.4 The values stated in SI units are to be regarded as the
3. Terminology
standard. The values in parentheses are provided for informa-
3.1 Definitions:
tion purposes only.
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
Yield, and Air Content (Gravimetric) of Concrete
traverse; 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 of the air voids in the
1
This test method is under the jurisdiction of ASTM Committee C09 on
concrete.
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
3.1.5 paste content (p)—Theproportionofthetotalvolume
C09.65 on Petrography.
of the concrete that is hardened cement paste expressed as
Current edition approved Jan. 1, 2006. Published January 2006. Originally
approved in 1960. Last previous edition approved in 1998 as C457–98.
percentage by volume.
2
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this test method.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM American Concrete Institute of Concrete Practice, issued annually, available
Standards volume information, refer to the standard’s Document Summary page on from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI
the ASTM website. 48333.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C 457–06
3.1.5.1 Discussion—When this parameter is calculated, it is 5. Significance and Use
the sum of the proportional volumes of the cement, the net
5.1 The parameters of the air-void system of hardened
mixing water (including the liquid portions of any chemic
...