Removal of chlorinated rubber coatings from concrete surfaces using an RF excited CO2 laser

This paper describes the effects of radio frequency excited CO2 laser (RF-CO2) radiation on the material characteristics of white chlorinated rubber (CR) paint on concrete substrates. Direct laser irradiation of a paint coating has been performed. Almost complete removal of the coating with very little to almost no damage (glazing or scabbling) to the concrete substrate has been achieved. Performing the process without additional process gas, i.e. purely with an optics shield gas resulted in the generation of a brittle ash layer, covering the coating and shielding it from further laser irradiation. Avoidance of this was accomplished by introducing a strong airflow parallel to the coating surface during the process. This resulted in almost perfect removal of the coating material down to the substrate. The residual ash has been analysed via EDX and SEM.