Laser Scabbling of a Concrete Block Using a High-Power Fiber Laser

A laser scabbling experiment was performed using a high-power fiber laser to investigate the removal rate of the concrete block and the scabbled depth. Concrete specimens with a 28-day compressive strength of 30 MPa were used in this study. Initially, we conducted the scabbling experiment under a stationary laser beam condition to determine the optimum scan speed. The laser interaction time with the concrete surface varied between 3 s and 40 s. The degree of spalling and vitrification on the surface was primarily dependent on the laser interaction time and beam power. Furthermore, thermal images were captured to investigate the spatial and temporal distribution of temperature during the scabbling process. Based on the experimental results, the scan speed at which the optical head moved over the concrete was set to be 300 mm.min(-1) or 600 mm.min(-1) for the 4.8-kW or 6.8-kW laser beam, respectively. The spalling rates and average depth on the concrete blocks were measured to be 87 cm(3).min(-1) or 227 cm3.min(-1) and 6.9 mm or 9.8 mm with the 4.8-kW or 6.8-kW laser beams, respectively.