Petrographic thin section
Definition
A slice of material ground to 30 micrometres and mounted on a glass slide for transmitted polarised light microscopy; the standard tool for identifying mineral phases, estimating proportions, and mapping microstructural features in concrete and mortar.
Related terms
- Aggregate
- The granular filler (sand, gravel, crushed rock) that occupies 60-80% of a concrete volume; its mineralogy, grain shape, and size distribution are...
- Calcium silicate hydrate (C-S-H)
- The principal binding phase produced when Portland cement reacts with water; a gel-like material that gives concrete most of its strength and...
- Carbonation front
- The boundary in concrete where atmospheric CO2 has converted portlandite to calcite; the depth of this front (measured in millimetres) is used...
- Ettringite
- A calcium sulfoaluminate hydrate that forms early in cement hydration and can re-form later from delayed sulfate attack; its presence or alteration...
- Portlandite
- Calcium hydroxide (Ca(OH)2) crystallised during cement hydration; a bright birefringent phase visible in thin section that dissolves progressively as concrete carbonates, providing...
Explained in
- Concrete, Mortar, and Cement as EvidenceA slice of material ground to 30 micrometres and mounted on a glass slide for transmitted polarised light microscopy; the standard tool for identifying mineral...