Full Name

ASTM C457 – Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete


This test method describes procedures for microscopical determinations of the air content of hardened concrete and of the specific surface, void frequency, spacing factor, and paste-air ratio of the air-void system in hardened concrete.

Three procedures are described:

  1. Procedure A – Linear-traverse method
  2. Procedure B – Modified point-count method
  3. Procedure C – Contrast enhanced method


air content; air void parameters of hardened concrete; area-prepared surface required; average chord-length of voids; determination of air-void parameters; entrained void; entrapped void; grits for lapping hardened concrete; index point; lapping; length of traverse required; linear-traverse method; microscopical; number of points required; paste-air ratio; paste-air ratio modification; paste content; point-count method (modified); specimen preparation for microscopical analysis; spacing factor; specific surface; void frequency; water void

ASTM C457 Accredited Laboratory

Applied Testing & Geosciences, LLC is accredited for performing tests using the ASTM C457 standard.

Contact us for more information.