To provide a continuous manufacturing device for a quick setting agent slurry having such advantages that the generation of dust can be reduced to a low level, the operating environments are ameliorated, the display of the same initial or long-term strength as seen in a conventional powdered quick setting agent can be expected and the spraying of the agent slurry to an exposed mountainous terrain or the like is achieved as well as a spray technique using this device.

The continuous manufacturing device for a quick setting agent slurry is structured of a supply pipe for a pressure-fed powdered quick setting agent, a water supply pipe and a discharge pipe for the quick setting agent slurry arranged opposite to the supply pipe through a gap, the inside diameter of the supply pipe being the same as that of the discharge pipe and the water supply pipe being connected to the supply pipe and the discharge pipe. Water is forced into the supply pipe and the discharge pipe through the gap to manufacture the quick setting agent slurry. This device is characterized in that the water supply angel is 10 to 90° with a supply pipe axis and the gap and the inside diameter of the supply pipe is 0.05 to 0.2 and further, that the water supply pressure is 0.05 to 3 MPa higher than the pressure at which the powdered quick setting agent is fed under pressure and the powdered quick setting agent contains a calcium aluminate. In addition, the spray technique is provided that the quick setting agent slurry manufactured by the continuous manufacturing device is added to and mixed with a cement concrete and the mixture is sprayed.