paper review

1. Removal of chlorinated rubber coatings from concrete surfaces using an RF excited CO_2 laser

Substrate:  Standard concrete slabs were used, which underwent a 4-month curing process and were dried to match typical moisture levels.

Paint Application: Chlorinated rubber (CR) paint was applied in three distinct layers.

Primer: Applied with a dry film thickness (DFT) of ~25 μm and dried for 24 hours.

Undercoat: Applied with a DFT of ~100 μm and dried for 24 hours.

Topcoat: Applied in 1-2 layers with a DFT of ~75 μm each, resulting in a final total coating thickness of ~250-275 μm.

Laser Equipment: A Coherent Diamond 84 CO₂ laser (wavelength 10.4–10.8 μm, power 25–150 W) was utilized. An unfocused ~7 mm diameter beam was scanned at speeds of 2.5–100 mm/s. 

Side Gas Jet (Optimal Condition): Air at ~3 bar was injected perpendicularly to the scanning direction at a 5° angle. This immediately removed the generated ash and provided a strong cooling effect, enabling complete paint removal down to the substrate without any concrete damage or residual ash.