ASTM C856 - 14

    Standard Practice for Petrographic Examination of Hardened Concrete

    Active Standard ASTM C856 | Developed by Subcommittee: C09.65

    Book of Standards Volume: 04.02


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    Abstract

    This practice outlines the standard procedures for performing petrographic examination of hardened concrete samples. The samples examined may be taken from concrete constructions, that is, all sorts of objects, units, or structures that have been built of hydraulic cement concrete. They may also be concrete products or portions thereof, or concrete or mortar specimens that have been exposed in natural environments or simulated service conditions, or subjected to laboratory tests. This practice applies to samples of all types of hardened hydraulic-cement mixtures, including concrete, mortar, grout, plaster, stucco, terrazzo, and the like. The equipments generally used for specimen preparation are diamond saw, cutting lubricant, horizontal lap wheels, free abrasive machine, polishing wheel, hot plate or oven, prospector's pick and/or bricklayer's hammer, abrasives, plate-glass squares, suitable media, and microscope slides. For specimen examination, the equipments needed are stereomicroscope, dollies, petrographic or polarizing microscope, metallographic microscope, eyepiece micrometer, stage micrometer, microscope lamps, needleholders and points, bottles with droppers, assorted forceps, lens paper, refractometer, and immersion media. Appropriate procedures for the sampling, preparation, and examination of specimens are detailed methodically.

    This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

    1. 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 1: A photographic chart of materials, phenomena, and reaction products discussed in Sections 8 – 13 and Tables 1-6 are available as Adjunct C856 (ADJC0856).

    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.

    Note 2: Appendix X1 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.

    1.3 The purposes of and procedures for petrographic examination of hardened concrete are given in the following sections:

     

    Section

     

    Qualifications of Petrographers and Use of Technicians

    4

    Purposes of Examination

    5

    Apparatus

    6

    Selection and Use of Apparatus

    7

    Samples

    8

    Examination of Samples

    9

    Specimen Preparation

    10

    Visual and Stereomicroscope Examination

    11

    Polarizing Microscope Examination

    12

    Paste Features

    13

    Report

    14

    1.4 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.

    1.5 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 and health practices and determine the applicability of regulatory limitations prior to use. A specific hazard statement is given in 6.2.10.1.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    C125 Terminology Relating to Concrete and Concrete Aggregates

    C215 Test Method for Fundamental Transverse, Longitudinal, and Torsional Resonant Frequencies of Concrete Specimens

    C227 Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)

    C342 Test Method for Potential Volume Change of Cement-Aggregate Combinations

    C441 Test Method for Effectiveness of Pozzolans or Ground Blast-Furnace Slag in Preventing Excessive Expansion of Concrete Due to the Alkali-Silica Reaction

    C452 Test Method for Potential Expansion of Portland-Cement Mortars Exposed to Sulfate

    C457 Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete

    C496/C496M Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens

    C597 Test Method for Pulse Velocity Through Concrete

    C803/C803M Test Method for Penetration Resistance of Hardened Concrete

    C805 Test Method for Rebound Number of Hardened Concrete

    C823 Practice for Examination and Sampling of Hardened Concrete in Constructions

    C1012 Test Method for Length Change of Hydraulic-Cement Mortars Exposed to a Sulfate Solution

    C1260 Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method)

    E3 Guide for Preparation of Metallographic Specimens

    E883 Guide for Reflected-Light Photomicrography

    ASTM Adjuncts

    AdjunctC856(ADJCO856 A chart of 27 photos Available from ASTM International Headquarters. Order Adjunct No. . Original adjunct produced in 1995.


    ICS Code

    ICS Number Code 91.100.30 (Concrete and concrete products)

    UNSPSC Code

    UNSPSC Code 30111500(Concrete and mortars)


    DOI: 10.1520/C0856-14

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