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Effects of Powder Additive on High-Volume Fly Ash Mixtures
ACI Materials Journal
  • David Newton Richardson, Missouri University of Science and Technology
  • Karl W. Beckemeier
  • Jeffery S. Volz, Missouri University of Science and Technology

Mitigation of problems in high-volume fly ash (HVFA) paste mixtures was explored using powder additives. Class C fly ash substitution levels of 25, 50, and 70% were examined at two levels of water reducer, gypsum, lime, and rapid-set cement (RSC) each. Compressive strength at 1, 3, 7, 28, and 56 days; semi-adiabatic calorimetry; Vicat setting time; and miniature slump were used for evaluation. Lime, RSC, or gypsum by themselves were not helpful in significantly improving early strengths. However, gypsum-lime was in some cases effective, but lowered later strength. Gypsum-RSC improved strengths at all ages. Gypsum by itself helped restore (retard) the fly ash-accelerated HVFA calorimeter curve positions, as did gypsum-RSC and gypsum-lime. Early stiffening tendencies were alleviated by gypsum and gypsum-lime, but made worse by gypsum-RSC. Diagnostic plots of semi-adiabatic peak heights, curve positions, and early stiffening were developed to aid in prediction of mixture combination behavior.

Civil, Architectural and Environmental Engineering
Keywords and Phrases
  • Additives,
  • C (programming language),
  • Calorimeters,
  • Calorimetry,
  • Compressive strength,
  • Concrete beams and girders,
  • Fly ash,
  • Lime,
  • Mixtures,
  • Adiabatic calorimetry,
  • Class C fly ashes,
  • Early strength,
  • High volume fly ash,
  • Peak height,
  • Rapid set,
  • Setting time,
  • Water reducers,
  • Gypsum,
  • High-volume fly ash,
  • Mixture incompatibilities,
  • Semi-adiabatic calorimetry
Document Type
Article - Journal
Document Version
File Type
© 2015 American Concrete Institute (ACI), All rights reserved.
Publication Date
Citation Information
David Newton Richardson, Karl W. Beckemeier and Jeffery S. Volz. "Effects of Powder Additive on High-Volume Fly Ash Mixtures" ACI Materials Journal Vol. 112 Iss. 4 (2015) p. 535 - 546 ISSN: 0889-325X
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