Method of Removing Graffiti from Surface of Concrete

The appearance of buildings and towns is ruined by graffiti drawn on walls made of concrete or brick. Much money and labor are spent in removing graffiti from such rough surface. This paper is a comparative study of the laser irradiation method and the high-pressure water jet method for removing graffiti from the surface of concrete. The former uses a YAG laser beam and the later uses water containing sodium bicarbonate particles. The graffiti were drawn in nine colors on the surface of concrete specimens using oil spray paint and emulsion spray paint. The main results of this study are as follows: Graffiti drawn with oil paint is easier to remove than that with emulsion paint. Yellow and orange colors are harder to remove compared to other colors. In both methods (laser irradiation and water jet) of removal, the surface of concrete is damaged only slightly. Overall, the laser irradiation method appears to be more effective for graffiti removal than the water jet method.