Who can do a petrographic examination of my concrete (ASTM C856)?
ASTM C856 describes the practice for microscopic examination of hardened concrete by a qualified petrographer. It is interpretive work — the petrographer's experience matters as much as the lab.
What the method covers
Cores or fragments of hardened concrete; examines paste, aggregate, air voids, cracking and evidence of deterioration mechanisms such as ASR.
Applicability caveats
- Petrography identifies evidence and likely mechanisms; it does not on its own predict remaining service life.
- Air void quantification is a separate method (ASTM C457) — request it explicitly.
- Expansion potential of aggregates is assessed by other methods (e.g. C1260, C1293).