Continuous wave laser grooving of cementitious materials

Fracture examination of brittle and quasi-brittle materials typically requires the creation of a sharp notch that involves removal of solid materials to nucleate a crack at a well-defined location. Here, we investigate the use of a 400 W continuous wave laser to create well-defined grooves in hardened cement-based materials. The influence of scanning speeds of a laser on the processing of cement-based materials was investigated using scanning electron microscopy (SEM) and confocal microscopy. The results show that for constant laser power below a certain scanning speed, redeposition of the material in the form of bridges across the groove decreases the effectiveness of the cut leading to an optimal combination of speed and laser power for sharp groove formation. Grooving cementitious material by laser processing enables significantly smaller grooves than those created using conventional methods, such as circular saws, and allows more precise control over location and cutting depth.