An experimental investigation of laser scabbling on cement-based materials using nanosecond fiber laser

In this study, the influence of a pulsed fiber laser of 250 W power with a spot size of 40 µm was successfully analyzed during scabbling of six types of cement mortar and three types of ultra-high-performance concrete (UHPC). Confocal microscopy on the surface of the scabbled samples elucidated the formation of three distinct zones: glassy layer (GL), partially melted zone (PMZ), and heat-affected zone (HAZ) with unique morphological appearances. The glassy layer exhibited bubble formation, whereas cracks were spotted alongside the scabbled area. The difference in scabbling depth between the beginning and end of the process was revealed by using 3D topography images. Moreover, the development of pores and the changes in the microstructure of each zone were observed by using scanning electron microscopy (SEM). Further energy dispersive X-ray (EDX) analysis also revealed significant changes in the percentage of silicon and calcium inside the glassy layer and non-processed zone (NPZ).