This Standard sets out the method for the petrographic examination of concrete aggregates or source rock that will identify those minerals and rock types that may react with alkali hydroxides in concrete pore solutions.

The method recognizes that most routine examinations are performed as an initial screening of materials and that all that is required is a qualitative indication of potential reaction. In limited instances, a more precise measure of the sample mineralogy may be warranted.

The method does not address the procedures for mineral or rock identification. It is assumed that the method will be used by a person who is trained and experienced in geology and petrography, with experience of materials used for concrete and with a good knowledge of alkali reactive aggregates and minerals.

The method is not applicable to alkali-carbonate reactive materials.