DECOLORIZING METHOD OF COLORED CONCRETE AND DECOLORIZING PIGMENT USED FOR THAT METHOD

摘要

PROBLEM TO BE SOLVED: To easily reuse a colored concrete residue without requiring a complicated treatment by adding a titanium oxide pigment or a decolorizing pigment which consists of a titanium oxide pigment and a pigment of the complementary color for the color of the colored concrete to the colored concrete. ;SOLUTION: A decolorizing pigment comprising 1 to 75 wt.% pigment of the complementary color for the color of the colored concrete and 99 to 25 wt.% of titanium oxide is mixed with 0.01 to 10 wt.% of a surfactant. The pigment of the complementary color is selected from magnetite, maghematite, hematite, hydrous iron oxide, chromium oxide, cobalt blue, phthalocyanine blue and phthalocyanine green. The mixture is treated by compressive deaeration and granulated to obtained a granular product having 300 to 1,500 μm average particle size and 0.1 to 0.3 porosity. A titanium oxide pigment or the granular product above described is added by 0.5 to 10 times of the weight of the color pigment included in the colored concrete to the colored concrete.;COPYRIGHT: (C)1998,JPO