Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM
Abstract
:1. Introduction
2. Materials and Methodology
2.1. Sample Information
2.2. Experimental Methods
2.3. Analytical Methods
3. Results
3.1. Subsection Hydration Products
3.2. Microstructure Characterization
3.3. Micro-Mechanical Properties of Slag Rim
3.3.1. Nanoindentation Combined with SEM-EDS
3.3.2. Frequency Histogram of Indentation Modulus and Hardness
4. Discussion
5. Conclusions
- (1)
- First, ~15 GPa higher modulus was obtained for slag rim compared with that of the C–S–H gel phase. Considering that the modulus of the C–S–H gel phase commonly varied around 20 GPa and it was in the range of 30~40 GPa for slag rim, it was concluded reasonably that the indentation modulus of the hydrotalcite-like phase was larger than ~40 GPa roughly.
- (2)
- At early age, slag cement paste mainly consisted of low-density C–S–H gel phase, high-density C–S–H gel phase, and unhydrated slag particles, as well as calcium hydroxide; at later age, the system contained C–S–H gel phase, slag rim (a mixture of C–S–H gel phase and hydrotalcite-like phase), and unhydrated slag particles.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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CaO | SiO2 | Al2O3 | MgO | FeO/Fe2O3 | TiO2 | MnO/Mn2O3 | Na2O | K2O | SO3 | Residual | |
---|---|---|---|---|---|---|---|---|---|---|---|
Cement | 64 | 20 | 5 | - | 3 | - | - | 0.58 | - | 2.93 | 4.49 |
Slag | 37.04 | 37.79 | 14.51 | 8.83 | 0.28 | 0.70 | 0.17 | 0.24 | 0.25 | 0.01 | 0.18 |
Phase | Pore | Hydrotalcite-Like Phase | C–S–H Gel Phase 1 | Anhydrous Slag Grains 2 |
---|---|---|---|---|
Grey Value | 0~50 | 50~100 | 100~160 | 160~255 |
Sample A | 0.91 ± 0.25 | 8.62 ± 1.32 | 47.34 ± 4.12 | 43.13 ± 3.38 |
Sample B | 0.32 ± 0.24 | 26.15 ± 2.46 | 51.59 ± 5.39 | 21.94 ± 2.79 |
Aggregate | Unhydrated Slag Particle | C–S–H | Slag Rim | ||||
---|---|---|---|---|---|---|---|
Indent | C1R5 | C7R6 | C6R5 | C7R5 | C5R6 | C9R6 | C10R5 |
Hardness | 4.80 | 3.00 | 0.62 | 0.45 | 0.64 | 0.96 | 0.98 |
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Zhang, Y.; Liang, M.; Gan, Y.; Çopuroğlu, O. Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM. Materials 2022, 15, 6347. https://doi.org/10.3390/ma15186347
Zhang Y, Liang M, Gan Y, Çopuroğlu O. Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM. Materials. 2022; 15(18):6347. https://doi.org/10.3390/ma15186347
Chicago/Turabian StyleZhang, Yu, Minfei Liang, Yidong Gan, and Oğuzhan Çopuroğlu. 2022. "Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM" Materials 15, no. 18: 6347. https://doi.org/10.3390/ma15186347