Changes of microstructural characteristics of cement-based material in scabbling process using nanosecond pulsed laser

Abstract

Laser scabbling is an advanced method used to remove surface defects in concrete such as cracking, glazing, salt contamination, corrosion, and even radiation-contaminated concrete surfaces in nuclear plants. Therefore, the microstructural changes in the processed concrete surface caused by laser treatment are essential for further research. In this study, two types of cement mortar and one type of ultra-high performance concrete (UHPC), were fabricated and scabbled by a 250 W laser with a spot size of 40 μm. After laser scabbling experiments, under a confocal microscope, three main types of zones were observed: processed zone, partially melted zone, and heat-affected zone. The morphological and phase changes of scabbled sample were identified using both optical and scanning electron microscopy (SEM), respectively. The microstructural reorganization of cement-based materials was also evaluated in each zone. Furthermore, the elemental redistribution of chemical elements was observed using energy dispersive X-ray spectroscopy (EDX) area mapping and point analysis.