1 Introduction
2 Test Scheme
2.1 Materials
Component | CaO | MgO | SiO2 | Fe2O3 | P2O5 | Al2O3 | SO3 | LOI |
---|---|---|---|---|---|---|---|---|
Cement | 54.65 | 2.58 | 22.07 | 4.32 | 1.03 | 6.30 | 2.59 | 2.14 |
Fly ash | 8.18 | 0.30 | 41.11 | 6.28 | 1.15 | 38.62 | 0.42 | 3.61 |
Slag powder | 45.09 | 6.99 | 27.33 | 0.45 | 0.13 | 13.66 | 4.03 | 0.95 |
2.2 2.2 Mix Proportion
No | Cement | Slag powder | Fly ash | Sand | RA | Water | PCA |
---|---|---|---|---|---|---|---|
RACC | 483 | 0 | 0 | 815 | 957 | 145 | 3.42 |
RACS | 241.5 | 241.5 | 0 | 815 | 957 | 145 | 3.42 |
RACSF | 241.5 | 144.9 | 96.6 | 815 | 957 | 145 | 3.42 |
2.3 Curing condition
Sample No | Static time /h | Heating time /h | Curing temperature /℃ | Holding time /h | Cooling time /h |
---|---|---|---|---|---|
RACS-6012 | 3 | 2 | 60 | 12 | 2 |
RACS-8009 | 80 | 9 |
Sample No | RACC | RACS | RACSF | RACS6012 | RACS8009 |
---|---|---|---|---|---|
Compressive strength | 59.6 | 61.4 | 51.9 | 56.7 | 54.6 |
2.4 X-Ray CT
3 Results and Discussion
3.1 Characteristic Analysis of Pore Structure
3.1.1 Porosity and Pore Size Distribution
3.1.2 Distribution of Pore Surface Area
Range of pore surface area/mm2 | 0–0.1 | 0.1–0.2 | 0.2–0.4 | 0.4–0.6 | 0.6–0.8 | 0.8–1.0 |
---|---|---|---|---|---|---|
RACC20 | 56.57 | 18.92 | 14.41 | 5.72 | 2.76 | 1.63 |
RACS20 | 63.42 | 17.20 | 11.82 | 4.28 | 2.07 | 1.20 |
RACSF20 | 58.78 | 18.26 | 13.53 | 5.27 | 2.56 | 1.60 |
RACS6012 | 52.90 | 20.52 | 15.82 | 6.12 | 2.89 | 1.76 |
RACS8009 | 58.78 | 18.26 | 13.53 | 5.27 | 2.56 | 1.60 |
3.1.3 Pore Fractal Dimension
3.1.4 Pore Sphericity
Pore sphericity | 0–0.275 | 0.275–0.0.475 | 0.475–0.675 | 0.675–0.825 | 0.825–0.925 | 0.925–0.975 |
---|---|---|---|---|---|---|
RACC20 | 0.17 | 1.99 | 9.50 | 22.79 | 30.94 | 34.59 |
RACS20 | 0.096 | 1.66 | 8.26 | 21.18 | 30.39 | 38.41 |
RACSF20 | 0.094 | 1.38 | 8.70 | 22.76 | 30.47 | 36.59 |
RACS6012 | 0.23 | 2.09 | 8.59 | 21.71 | 30.76 | 36.61 |
RACS8009 | 0.19 | 2.30 | 10.24 | 23.55 | 31.21 | 32.51 |
3.1.5 Pore Shape Factor
Classification | Stretch ratio | Flatness ratio | Shape |
---|---|---|---|
I | > 0.67 | < 0.67 | Pie |
II | > 0.67 | > 0.67 | Spherical |
III | < 0.67 | < 0.67 | Bladed |
IV | < 0.67 | > 0.67 | Rod |
Sample No. | Pie (%) | Spherical (%) | Bladed (%) | Rod (%) |
---|---|---|---|---|
RACC20 | 15.18 | 20.46 | 47.51 | 16.83 |
RACS20 | 16.13 | 22.31 | 43.38 | 18.18 |
RACSF20 | 15.95 | 23.17 | 42.20 | 18.68 |
RACS6012 | 16.32 | 21.08 | 42.71 | 19.89 |
RACS8009 | 14.92 | 12.95 | 53.35 | 18.78 |