Title: Alkali Silica Reaction Processes: The Conversion of Cement Alkalies to Alkali Hydroxide

Author(s): Sidney Diamond and Michael Penko

Publication: Symposium Paper

Volume: 131

Issue:

Appears on pages(s): 153-168

Keywords: alkalies; alkali-silica reactions; ettringite; gypsum; pore solutions; porosity; sulfates; Materials Research

DOI: 10.14359/1206

Date: 3/1/1992

Abstract:
Among the important stages of the overall SR process as it occurs in concrete is the conversion of alkali sulfate dissolved from the cement to alkali hydroxide. The results of laboratory studies are presented to provide an understanding of this process and its effects. This conversion process depends on continued formation of ettringite and does not take place until the cement gypsum is exhausted. Provision of a large excess of gypsum or interference with early ettringite production by high-temperature exposure may postpone or prevent it, thus reducing the OH - ion concentration and the possibility of ASR reaction.