| abstract |
(57) [Abstract] [PROBLEMS] To provide a method for producing a hardened colored cement, which is hardly faded even when exposed to a natural environment for a long time. First, a pigment 12 is subjected to a low temperature plasma treatment in which a plasma 20 of oxygen gas, inorganic gas or water vapor is irradiated. Next, the pigment 12 after this treatment is taken out of the apparatus and mixed with the hydraulic cement hardened material, Further, water is added to the cement hardened material after the mixing to harden it. |