ASTM C295/C295M-19 pdf free download.Standard Guide for Petrographic Examination of Aggregates for Concrete.
1.1 This guide outlines procedures for the petrographic examination of samples representative of materials proposed for use as aggregates in cementitious mixtures or as raw materials for use in production of such aggregates. This guide is based on Ref (1).
1.2 This guide outlines the extent to which petrographic techniques should he used, the selection of properties that should he looked for, and the manner in which such techniques may he employed in the examination of samples of aggregates for concrete.
1.3 The rock and mineral names given in Descriptive Nomenclature C294 should he used, insofar as they are appropriate, in reports prepared in accordance with this guide.
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 may not he exact equivalents: therefore, each system shall he used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
3. Qualifications of Petrographers
3.1 All pctrographic examinations of aggregate for use in concrete as described in this guide should be performed by a petrographer with at least 5 years experience in petrographic examination of concrete or concrete-making materials. The petrographer should have completed college-level course work pertaining to basic geology, mineralogy, petrography, and optical mineralogy or have obtained equivalent knowledge through experience and on-the-job training. Completion of course work in concrete materials is also advantageous. The petrographer should have experience evaluating the effects of aggregates on the physical and chemical properties of hardened concrete. Identification of individual minerals in aggregate particles, classification of rock types. and categorizing the physical and chemical properties of rocks and minerals should also he included in the petrographer’s experience. The petrographer should have expertise to properly use the equipment and apparatus described in Section 6 and provide detailed interpretations of the pctrographic examination. If the petrographer does not meet these qualifications, the individual may perform such examinations under the technical direction of a full-time supervising petrographer who meets these qualifications. A resume of the professional experience and education of the petrographer shall be available.
3.1.1 Licensing. certification, or other accreditation by a governmental agency or other organization stating the mdividual is a professional geologist should not, by itself, constitute sufficient qualification for examination of aggregates for concrete.ASTM C295/C295M pdf download.