Abstract
In the present work, the relationship between the composition of the SiO2–Al2O3–CaO precursor system and the setting time, microstructure and mechanical properties of the resulting alkali-activated cement (AAC) were investigated. The results showed that with the increase of metakaolin content and the modulus of activator solution, setting time of alkali-activated cements was prolonged. The compressive strength increased with the increase of CaO content to a certain extent, but had different trends as Si/Al ratio varied. Microstructural analyses revealed that CaO content had remarkable effects on the microstructure of AAC. In calcium-free system, the strength was dependent on the three-dimensional structure of N–A–S–H gels. As the CaO content increased gradually, the main activation product changed from N–A–S–H to C–(A)–S–H gel, resulting in a more compact structure. This investigation helps to build up a practical approach for the composition design of alkali-activated cements.
Original language | English |
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Article number | 178 |
Pages (from-to) | 1-11 |
Number of pages | 11 |
Journal | Materials and Structures |
Volume | 50 |
DOIs | |
Publication status | Published - 11 May 2017 |
Keywords
- alkali-activation
- SiO2–Al2O3–CaO system
- composition design
- setting time
- strength
- microstructure