期刊
CEMENT AND CONCRETE RESEARCH
卷 87, 期 -, 页码 1-13出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.cemconres.2016.05.004
关键词
Kinetics; pH; Glass; Alkali-aggregate reaction; Pozzolan
资金
- National Science Foundation (NSF) [1030708]
- CAREER [1254333]
- Directorate For Engineering
- Div Of Civil, Mechanical, & Manufact Inn [1030708] Funding Source: National Science Foundation
- Div Of Civil, Mechanical, & Manufact Inn
- Directorate For Engineering [1254333] Funding Source: National Science Foundation
A better understanding of silica dissolution-precipitation reactions at high pH aqueous solutions allows for promotion of favorable (e.g., pozzolanic) reactions and mitigation of deleterious (e.g., alkali-silica) reactions in concrete. In this paper, the kinetics and products of silica glass dissolution are studied as a function of solution pH, temperature, and availability of calcium. It was observed that dissolution rate versus time increases linearly with pH and reaches a maximum at pH = 14, with slower dissolution at higher alkalinities. In solutions with similarly high pH, but saturated with portlandite, glass dissolution is significantly slower. This is due to formation of a dense, low porosity, and strongly bonded C-S-H layer on the surface of glass, which serves as a barrier against diffusion of OH- and alkali ions towards the substrate glass. This protective layer forms only when Ca is abundant and portlandite saturation can be maintained on a local scale. (C) 2016 Elsevier Ltd. All rights reserved.
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