Method of decoloring colored concrete

摘要

A method of decoloring a colored concrete, comprises adding to the colored concrete, a decoloring pigment comprising a titanium oxide pigment, or a titanium oxide pigment and a pigment having a complementary color relative to color of the colored concrete. Such method can decolore the color of the colored concrete residue which attaches to or remains in production facilities in order to return a color thereof to that of an ordinary plain concrete, without works or treatments for washing-out or removing the colored concrete residue which attaches to or remains in the production facilities, in which the works or treatments are required in the case where the production facilities are used for the production of an ordinary plain concrete after the colored concrete has been produced therein, and without works or treatments for purifying a waste water generated upon washing-out or removing the residue and for making the waste water harmless; and a pigment used therefor.