抄録
In order to investigate the influence of calcium chloride on portland and portland blastfurnace cement, the author tested the various properties of the paste, mortar and concrete made with normal portland cement, portland blastfurnace cement and other pozzolanic cements, with the addition of the various amount of calcium chloride (CaCl2·2H2O).
The results are summarized as follows:
1. Portland and portland blastfurnace cement, containing insufficient amount of gypsum, which showed flash set or abnormal slow set show the nearly normal set, by the addition of the suitable amount of calcium chloride.
2. By the addition of calcium chloride in amount of 1-3 percent by weight of cement, the mortar and concrete made with portland blastfurnace cement, show higher strength at early ages than those of normal portland cement without this salt, and yet thereafter show similar strength at later ages to the portland blastfurnace cement without this salt.
3. By the addition of calcium chloride, portland blastfurnace cement shows the beneficial property in promoting early higher strength than other pozzolanic cements.
4. Portland blastfurnace cement requirer larger amount of calcium chloride for the occurence of flash set than normal portland cement.
5. The addition of calcium chloride increases progressively an entrained air content in mortar and concrete, mortar flow and concrete slump.
6. The premature stiffened paste, mortar and concrete, made with aerated fake setting cement, resume its plasticity slightly, by the addition of the suitable amount of calcium chloride.
