Air void analysis

PELCON conducts accredited Automated Air Void Analysis according to ASTM C-457. Our long experience and continous improvement of the procedures ensures a high quality of the prepared specimens. All specimens are checked several times during the preparation.

The analysis is conducted using true automated linear traverse equipment. Final results are validated by an internal manual process and by reference specimens.

During the measurement the polished and contrast impregnated specimen is moved in parallel lines below the microscope to cover full surface area; chords are recorded with ~2 microns resolution.

We have more than 20 years experience. Our experience after more than 5,000 samples measured fulfils our understanding and performance of this analysis.

Our results are regularly documented by Round Robin Tests.

Highlights from specimen preparation

Black&White picture of the final contrast impregnated specimen ready for analysis
Size: 100x100mm
Check list

  • Surface completely plane
  • Surface evenly ground in full area
  • No pull-outs or scratches
  • No relief at aggregate/paste interface
  • Air voids of circular outlines
  • Paste not funnel-shapes at air voids
  • No grinding sludge in pores
  • Blue dye applied evenly
  • Small pores not filled by blue dye
  • All air voids filled with whiting
  • No holes in whiting
  • Blue surface cleaned from whiting
  • Porous aggregate blocked-out
  • Full specifmen focussed in analyser
  • Individual setting
  • Manual 10% check counting
  • Comparison to reference catalogue
  • Results confirmed

The automated analysis

Test Report

Typical mistakes in specimen preparation

Making an air void analysis on samples like these will surely give you a misleading result.

– Specimen preparation is a crucial issue.