کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7885337 | 1509746 | 2015 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A thermodynamic and kinetic model for paste-aggregate interactions and the alkali-silica reaction
ترجمه فارسی عنوان
یک مدل ترمودینامیکی و جنبشی برای تداخل خمیدگی و واکنش سیلیکا قلیایی
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی صنعتی و تولید
چکیده انگلیسی
A new conceptual model is developed for ASR formation based on geochemical principles tied to aqueous speciation, silica solubility, kinetically controlled mineral dissolution, and diffusion. ASR development is driven largely by pH and silica gradients that establish geochemical microenvironments between paste and aggregate, with gradients the strongest within the aggregate adjacent to the paste boundary (i.e., where ASR initially forms). Super-saturation of magadiite and okenite (crystalline ASR surrogates) occurs in the zone defined by gradients in pH, dissolved silica, Na+, and Ca2Â +. This model provides a thermodynamic rather than kinetic explanation of why quartz generally behaves differently from amorphous silica: quartz solubility does not produce sufficiently high concentrations of H4SiO4 to super-saturate magadiite, whereas amorphous silica does. The model also explains why pozzolans do not generate ASR: their fine-grained character precludes formation of chemical gradients. Finally, these gradients have interesting implications beyond the development of ASR, creating unique biogeochemical environments.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cement and Concrete Research - Volume 76, October 2015, Pages 107-120
Journal: Cement and Concrete Research - Volume 76, October 2015, Pages 107-120
نویسندگان
George D. Guthrie, J. William Carey,