| Early Hydration Properties of Calcium Aluminosulfate (3CaO · 3Al2O3 · CaSO4) Prepared by Chemical Synthesis |
| Hoon-Sang Kim, Hyung-Chul Kim, Jong-Taek Song |
| Department of Materials Science and Engineering, Dankook University |
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| ABSTRACT |
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Calcium aluminosulfate (3CaO.3Al$_2$O$_3$.CaSO$_4$or $C_4$A$_3$S) was prepared by chemical synthesis from the nitrate salts and aluminum sulfate. $C_4$A$_3$S was the main phase after calcination at 110$0^{circ}C$. The specific surface areas after calcination at 110$0^{circ}C$ and 130$0^{circ}C$ were about 2.5 and 1.0 $m^2$/g, respectively. Hydration was investigated by XRD, DSC, SEM, EDS, conduction calorimetry and analysis of the liquid phase. Calorimetry showed that the induction period was longer than that of a sample prepared by conventional solid state sintering and this was attributed to the formation of amorphous coatings in abundance of $Al_2$O$_3$ and SO$_3$. Crystalline hydration products, principally calcium monosulfoaluminate hydrate and Al(OH)$_3$, appeared subsequently.ᜎࠀ ࠀ㘲㌮㠵㘻Ԁ䭃䑎䷕᜕ఽ 0〳⸵㬅K䍄乍븗ጊ缀 Ѐ㘰〻Ԁ䭃䑎䶩ഏ 3㠴⸰㠻Ԁ䭃䑎䴀 |
| Key words:
$C_4$$A_3$S, Induction period, Amorphous coating, Calcium monosulfoaluminate, Al(OH) |
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