ASTM C 856/C 856M:2025

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. 1.2 The petrographic procedures outlined herein are applicable to the examination of samples of all types of hardened 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 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 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. Note 1: Sieve size is identified by its standard designation in Specification E11 . The alternative designation given in parentheses is for information only and does not represent a different standard sieve size. 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. 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.

91.100.30