Chapter 29. Extrusion of Lightweight Construction Materials from Fly Ash

  1. John B. Wachtman Jr.
  1. H. D. Deford and
  2. G. P. Wirtz

Published Online: 28 MAR 2008

DOI: 10.1002/9780470314050.ch29

A Collection of Papers Presented at the 94th Annual Meeting and the 1992 Fall Meeting of the Materials & Equipment/Whitewares Manufacturing: Ceramic Engineering and Science Proceedings, Volume 14, Issue 1/2

A Collection of Papers Presented at the 94th Annual Meeting and the 1992 Fall Meeting of the Materials & Equipment/Whitewares Manufacturing: Ceramic Engineering and Science Proceedings, Volume 14, Issue 1/2

How to Cite

Deford, H. D. and Wirtz, G. P. (1993) Extrusion of Lightweight Construction Materials from Fly Ash, in A Collection of Papers Presented at the 94th Annual Meeting and the 1992 Fall Meeting of the Materials & Equipment/Whitewares Manufacturing: Ceramic Engineering and Science Proceedings, Volume 14, Issue 1/2 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314050.ch29

Author Information

  1. Department of Materials Science and Engineering University of Illinois Urbana, IL 61801

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1993

ISBN Information

Print ISBN: 9780470375235

Online ISBN: 9780470314050

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Keywords:

  • honeycomb shapes;
  • liquid phase;
  • area fraction;
  • honeycomb structure;
  • wall density

Summary

Class C fly ash was evaluated for potential use in lightweight structural applications. Honeycomb-shaped fly ash bodies were extruded and fired, using boric acid as a liquid phase sintering aid. Strengths of 55 MPa were obtained for samples with bulk densities of 0.98 g/cm3. The bulk density was empirically modeled as a function of the area fraction of solid in the honeycomb cross section and the honeycomb wall density. It was assumed for these honeycomb shapes that the macrostructural incorporation of large, continuous voids along the extrusion axis would reduce the strength linearly, as opposed to the exponential decrease normally observed for ceramics with random microstructural porosity. The model allows prediction of the wall density needed to attain a desired bulk density-strength combination. The minimum wall density determines the solid area fraction that, after correction for densification, would be used to design the appropriate die.