ISSN: 0149-6123
Page Count: 7

Expandability of Solid-Volume-Reducing Reactions of Alkali-Magnesite and Alkali-Dolomite
Tong, L
Post doctoral fellow, Tsinghua University,

Tang, M
Professor of materials science, Nanjing University of Chemical Technology,

Abstract

The work presented in this paper concerns two solid-volume-reducing reactions between alkali-dolomite (ADR) and alkalimagnesite (AMR). It was found that the two reactions can cause considerable expansion of compacts made from dolomite or magnesite powder and 20% Portland cement when cured at 150 and 60°C in 10% KOH solution. The results confirmed an earlier suggestion that the formation and growth of crystalline products in a confined space may be expandable.

The expandability of the alkali-magnesite reaction was first recognized by the authors using newly developed test methods—150°C autoclaving of concrete microbars and miniature rock prism tests. Although magnesite itself is rarely used as a concrete aggregate, it is reasonable to investigate the reaction since concrete aggregates may contain a certain amount of magnesite.

Keywords:
alkali-carbonate reaction, expansion of concrete, alkali-silica-reaction, freeze-thaw process, sulfate expansion, carbonation

Paper ID: CCA10019J
DOI: 10.1520/CCA10019J
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