A Cementless Binder Based on High-Calcium Fly Ash, Silica Fume, and the Complex Additive Ca(NO3)2 + MgCl2: Phase Composition, Hydration, and Strength

This study aimed to comprehensively investigate the properties of a binder based on high-calcium fly ash and silica fume with a complex additive consisting of calcium nitrate and magnesium chloride. The strength characteristics, the characteristics of the hydration process, and the phase composition of the hydration products of the binder were investigated. Silica fume was used to suppress the expansion of fly ash during hydration. A complex additive (CA) consisting of Ca(NO3)2 and MgCl2 provided a higher strength of binder than each of these salts separately. When testing a mortar with sand, the CA additive ensured that the strength of the specimens was 43.5% higher than the strength of the mortar with the addition of Ca(NO3)2 and 7.5% higher than the strength of the mortar with the MgCl2 additive. Calcium nitrate greatly accelerated the process of heat release in the first 60 min of binder hydration, and subsequently, conversely, slowed it down. The addition of MgCl2 gave a significantly greater thermal effect than Ca(NO3)2. When the two salts acted together, even a small fraction of magnesium chloride (0.2 of CA) compensated for the retarding effect of calcium nitrate and provided heat release for the binder that was almost as good as that of MgCl2.

Авторы
Barabanshchikov Yurii1 , Usanova Kseniia 1, 2
Журнал
Издательство
MDPI Multidisciplinary Digital Publishing Institute
Номер выпуска
7
Язык
Английский
Страницы
2121
Статус
Опубликовано
Том
14
Год
2024
Организации
  • 1 Institute of Civil Engineering, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
  • 2 Academy of Engineering, RUDN University, 117198 Moscow, Russia
Ключевые слова
binder; hydration; microsilica; calcium nitrate; magnesium chloride; phase composition; strength; heat generation; heat of release
Дата создания
27.09.2024
Дата изменения
27.09.2024
Постоянная ссылка
https://repository.rudn.ru/ru/records/article/record/157540/
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