| Author: | Wang, Yanshuai |
| Title: | Influence of metal ions on formation of silico-aluminophosphate geopolymer |
| Advisors: | Dai, Jian-guo (CEE) |
| Degree: | Ph.D. |
| Year: | 2018 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Polymeric composites Polymers |
| Department: | Department of Civil and Environmental Engineering |
| Pages: | xxii, 208 pages : color illustrations |
| Language: | English |
| Abstract: | Portland cement as the most widely used construction material plays a significant role on the global urbanization. However, numerous crises (e.g., environmental issues) coming with this progress have been emerging. Geopolymer cement (or chemically-activated cement [CAC] defined by other researchers) is an attractive alternate to the traditional Portland cement because such a type of cement can be calcination-free and derived through chemical reactions (e.g., gels formation and geopolymerization) between industrial by-products or natural minerals (i.e., aluminosilicate precursors) and activating solutions (e.g., alkali-silica or phosphate). This thesis focuses on the influences of metal ions on the microstructural modification during the formation of silico-aluminophosphate geopolymer. An in-depth understanding of the material formation mechanism is believed to be a key to tailor this type of geopolymer to meet specific performance requirements in different engineering applications. The study mainly involves four dimensions: (1) Synthesis of silico-aluminophosphate geopolymer based on a theoretical Si-Al-P ratio which is supported by a hypothetical molecular structure; (2) Improvement of the workability and setting time of silico-aluminophosphate geopolymer by incorporating aluminate species into the phosphate activator; (3) Use of dead-burnt magnesia-doped aluminosilicate precursor to induce acid-base reaction during the geopolymerization for improving the early age performance of silico-aluminophosphate geopolymer; (4) Use of high-calcium coal fly ash as the calcium donor during geopolymerization to acquire the castable silico-aluminophosphate geopolymer with high early strength. Aluminum-incorporated phosphate activation and magnesium/calcium-doped aluminosilicate precursors (e.g., dead-burnt magnesia and high-calcium coal fly ash) were extensively studied and found to be effective to modify both the fresh and hardened properties of silico-aluminophosphate geopolymer. The knowledge arisen from the thesis has facilitated a solid basis for a wide range of engineering applications of this new category of geopolymer cement. |
| Rights: | All rights reserved |
| Access: | open access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022164558603411.pdf | For All Users | 7.28 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/9591