Mechanical Properties and Microstructure of Class C Fly Ash-Based Geopolymer Paste and Mortar
Abstract
:1. Introduction
2. Experimental Test
2.1. Materials
2.2. Mixture Design and Specimen Preparation
2.2.1. Mixture Design
2.2.2. Specimen Preparation and Methods for Analysis
3. Results and Discussion
3.1. Fluidity
Geopolymer | Water-to-fly ash ratio | Fluidity (mm) | |
---|---|---|---|
30 s | 30 min | ||
Geopolymer paste | 0.30 | 145 | 162 |
0.32 | 169 | 192 | |
0.35 | 173 | 195 | |
Geopolymer mortar | 0.30 | - | - |
0.32 | 131 | ||
0.35 | 136 |
3.2. Compressive Strength
3.3. Microstructure
3.3.1. XRD Analysis
3.3.2. SEM Analysis
4. Conclusions
- (1)
- For class C fly ash-based geopolymer paste, low W/F could meet the demand for an approving fluidity. Increases in the concentration of sodium hydroxide decreased the fluidity of the mixes. As sand aggregates were added, fluidity decreased distinctly;
- (2)
- Class C fly ash-based geopolymer paste and mortar could both obtain high compressive strength after curing at 70 °C for 24 h. Compressive strength of mortar was much higher than paste with the same water-to-fly ash ratio;
- (3)
- In the XRD patterns of the paste and mortar samples, broad band diffraction peaks around 30 degrees of 2theta show that gels have been formed in these samples. SEM analysis revealed that the dense structures of mortar and paste contribute to the high compressive strength.
Acknowledgments
References
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Li, X.; Ma, X.; Zhang, S.; Zheng, E. Mechanical Properties and Microstructure of Class C Fly Ash-Based Geopolymer Paste and Mortar. Materials 2013, 6, 1485-1495. https://doi.org/10.3390/ma6041485
Li X, Ma X, Zhang S, Zheng E. Mechanical Properties and Microstructure of Class C Fly Ash-Based Geopolymer Paste and Mortar. Materials. 2013; 6(4):1485-1495. https://doi.org/10.3390/ma6041485
Chicago/Turabian StyleLi, Xueying, Xinwei Ma, Shoujie Zhang, and Enzu Zheng. 2013. "Mechanical Properties and Microstructure of Class C Fly Ash-Based Geopolymer Paste and Mortar" Materials 6, no. 4: 1485-1495. https://doi.org/10.3390/ma6041485