ASTM C856-95e1
(Practice)Standard Practice for Petrographic Examination of Hardened Concrete
Standard Practice for Petrographic Examination of Hardened Concrete
SCOPE
1.1 This practice outlines procedures for the petrographic examination of samples of hardened concrete. The samples examined may be taken from concrete constructions, they may be concrete products or portions thereof, or they may be concrete or mortar specimens that have been exposed in natural environments, or to simulated service conditions, or subjected to laboratory tests. The phrase "concrete constructions" is intended to include all sorts of objects, units, or structures that have been built of hydraulic cement concrete. Note-A photographic chart of materials, phenomena, and reaction products discussed in Sections 7 through 12 and Tables 1 through 6 are available as Adjunct C856.
1.2 The petrographic procedures outlined herein are applicable to the examination of samples of all types of hardened hydraulic-cement mixtures, including concrete, mortar, grout, plaster, stucco, terrazzo, and the like. In this practice, the material for examination is designated as "concrete," even though the commentary may be applicable to the other mixtures, unless the reference is specifically to media other than concrete.
1.3 Annex A1 outlines an uranyl acetate method for identifying locations where alkali-silica gel may be present. It is a requirement that the substances in those locations must be identified using any other more definitive techniques, such as petrographic microscopy.
1.4 The purposes of and procedures for petrographic examination of hardened concrete are given in the following sections: Section Qualifications of Petrographers 3 Purposes of Examination 4 Apparatus 5 Selection and Use of Apparatus 6 Samples 7 Examination of Samples 8 Specimen Preparation 9 Visual and Stereomicroscope Examination 10 Polarizing Microscope Examination 11 Metallographic Microscope Examination 12 Report 13
1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units in parentheses are provided for information purposes only.
1.6 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 and health practices and determine the applicability of regulatory limitations prior to use. A specific hazard statement is given in 5.2.10.1.
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Standards Content (Sample)
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Designation: C 856 – 95
Standard Practice for
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Petrographic Examination of Hardened Concrete
This standard is issued under the fixed designation C 856; 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 (e) indicates an editorial change since the last revision or reapproval.
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e NOTE—Values for (OH ) within formulas in Table 6 were editorially corrected in September 1999 to (OH) .
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1. Scope
Section
Polarizing Microscope Examination 11
1.1 This practice outlines procedures for the petrographic
Metallographic Microscope Examination 12
examination of samples of hardened concrete. The samples Report 13
examined may be taken from concrete constructions, they may
1.5 The values stated in inch-pound units are to be regarded
be concrete products or portions thereof, or they may be
as the standard. The SI units in parentheses are provided for
concrete or mortar specimens that have been exposed in natural
information purposes only.
environments, or to simulated service conditions, or subjected
1.6 This standard does not purport to address all of the
to laboratory tests. The phrase “concrete constructions” is
safety concerns, if any, associated with its use. It is the
intended to include all sorts of objects, units, or structures that
responsibility of the user of this standard to establish appro-
have been built of hydraulic cement concrete.
priate safety and health practices and determine the applica-
NOTE 1—A photographic chart of materials, phenomena, and reaction
bility of regulatory limitations prior to use. A specific hazard
products discussed in Sections 7-12 and Tables 1-6 are available as
statement is given in 5.2.10.1.
Adjunct C856.
2. Referenced Documents
1.2 The petrographic procedures outlined herein are appli-
cable to the examination of samples of all types of hardened
2.1 ASTM Standards:
hydraulic-cement mixtures, including concrete, mortar, grout,
C 42 Test Method for Obtaining and Testing Drilled Cores
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plaster, stucco, terrazzo, and the like. In this practice, the
and Sawed Beams of Concrete
material for examination is designated as “concrete,” even
C 215 Test Method for Fundamental Transverse, Longitu-
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though the commentary may be applicable to the other mix-
dinal, and Torsional Frequencies of Concrete Specimens
tures, unless the reference is specifically to media other than
C 227 Test Method for Potential Alkali Reactivity of
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concrete.
Cement-Aggregate Combinations (Mortar-Bar Method)
1.3 Annex A1 outlines an uranyl acetate method for identi-
C 294 Descriptive Nomenclature of Constituents of Natural
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fying locations where alkali-silica gel may be present. It is a
Mineral Aggregates
requirement that the substances in those locations must be
C 295 Guide for Petrographic Examination of Aggregates
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identified using any other more definitive techniques, such as
for Concrete
petrographic microscopy.
C 342 Test Method for Potential Volume Change of
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1.4 The purposes of and procedures for petrographic exami-
Cement-Aggregate Combinations
nation of hardened concrete are given in the following sections:
C 441 Test Method for Effectiveness of Mineral Admixtures
Section
or Ground Blast-Furnace Slag in Preventing Excessive
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Expansion of Concrete Due to the Alkali-Silica Reaction
Qualifications of Petrographers 3
C 452 Test Method for Potential Expansion of Portland
Purposes of Examination 4
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Apparatus 5
Cement Mortars Exposed to Sulfate
Selection and Use of Apparatus 6
C 457 Practice for Microscopical Determination of Air-Void
Samples 7
Content and Parameters of the Air-Void System in Hard-
Examination of Samples 8
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Specimen Preparation 9
ened Concrete
Visual and Stereomicroscope Examination 10
C 496 Test Method for Splitting Tensile Strength of Cylin-
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drical Concrete Specimens
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C 597 Test Method for Pulse Velocity Through Concrete
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This practice is under the jurisdiction of ASTM Committee C09 on Concrete
and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.65on
Petrography.
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Current edition approved Dec. 10, 1995. Published March 1996. Originally Annual Book of ASTM Standards, Vol 04.02.
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published as C 856 – 77. Last previous edition C 856 – 83 (1998)e . Annual Book of ASTM Standards, Vol 04.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
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C856–95
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TABLE 1 Visual Examination of Concrete (1)
Coarse Aggregate + Fine Aggregate +
...
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