WHAT IS CONCRETE PETROGRAPHY?

Petrography is the examination and description of the structure and composition of rocks and rocklike materials. Concrete Petrography is the application of petrographic techniques to concrete quality control and failure analysis. Petrographic methods are also applicable to a wide variety of other construction materials including brick, stucco, stone, tile, and plaster.

The principal tool of the concrete petrographer is the polarized-light or petrographic microscope. Polished slabs and transparent thin sections of concrete samples are examined at up to 500x magnification with a variety of illumination techniques to permit identification of the components of the concrete and their relationship to one another.

The American Society for Testing and Materials has established widely accepted standard practices for the petrographic analysis of concrete and aggregate. The applicable standards are:

ASTM C-856
Petrographic Examination of Hardened Concrete

ASTM C-295
Petrographic Examination of Aggregates for Concrete

ASTM C-457
Microscopic Determination of Air-Void Content