When 12CaO⋅7Al
2O
3 was dispersed in aqueous solution at 20°C, the quantities of effluent calcium and aluminium in various durations indicated the super saturation phenomena. On the other hand, when 12CaO⋅7Al
2O
3 was dispersed in solution of Ca(OH)
2, it was suggested generally that these quantities were greatly decreased because of the formation of 2CaO⋅Al
2O
3⋅8H
2O.
However, the quantity of effluent calcium was increased also in solution of Ca(OH)
2. The processes are seemed different from those found in the previous reports. 2CaO⋅Al
2O
3⋅8H
2O was detected at the time of elimination of super saturation phenomenon.
Furthermore, the authors confirmed by the electro-conductivity as well as the effluent quantities. The change of electro-conductivity vs. the hydration time was closely connected with the effluent quantities. Namely, it is apparent from the results of experiments that the maximum phenomenon on the electro-conductivity curves have existed also in solution of Ca(OH)
2.
The hydration processes of 12CaO⋅7Al
2O
3 in solution of Ca(OH)
2 were observed by scanning electron microscopic photographs. Accordingly, it was elucidated the products of card house states consisted of 4CaO⋅Al
2O
3⋅13H
2O and 2CaO⋅Al
2O
3⋅8H
2O in the early hydration processes. Therefore, the flash setting of 12CaO⋅7Al
2O
3-Ca(OH)
2 system is produced by the formation of card house states.
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