| abstract |
This rapid hardening agent for a spray contains a calcium aluminate and an aluminum sulfate, and does not contain an alkali metal aluminate and an alkali metal hydroxide, wherein the content of the aluminum sulfate is 5-105 parts by mass with respect to 100 parts by mass of the calcium aluminate, and the content of an alkaline earth metal in the aluminum sulfate is 0.007-4 mass% in terms of an alkaline earth metal oxide. |