Title:
Studying Air Voids on Cylindrical Surfaces
Author(s):
L. Brad Shotwell
Publication:
Concrete International
Volume:
23
Issue:
8
Appears on pages(s):
69-74
Keywords:
DOI:
Date:
8/1/2001
Abstract:
Petrographers routinely use the modified point-count method outlined in ASTM C 457 to determine the parameters of hardened-concrete air-void systems. This method requires cutting a planar surface from the center of the submitted core sample and then polishing the surface by lapping, using progressively finer silicon-carbide abrasives. Using a mechanical point-count stage, the petrographer then makes equally spaced lines of traverse across the prepared surface. ASTM C 45 shows photographs of a prepared planar surface (Section 8) and the point-count stage (Section 12). Petrographers can also use this method to measure the volume of the cementitious matrix of hardened concrete, and, if they can distinguish the coarse and fine aggregates contained in the hardened concrete sample, to measure aggregate volumes.