Effect of Laser Speed on Cutting Characteristics of Cement-Based Materials.

The results of an experimental investigation on the physical and chemical characteristics of cement-based materials under laser interactions are presented. The laser cutting tests were conducted using a multi-mode continuous fiber laser with a laser power of 1 kW. The experimental variables were laser speed, water to cement ratio, and material compositions including cement paste, cement mortar, and ultra high-performance concrete (UHPC). In order to evaluate the mass removal mechanisms of cement-based materials under laser interactions, the effect of laser cutting was evaluated in terms of kerf width, penetration depth, and chemical composition changes before and after the interaction with laser using EDX analysis. The test results reveal that adding silica sand in cement-based materials leads to decreasing penetration depth and increasing kerf width. Unlike the cement paste and cement mortar series, UHPC specimens showed no discernible crack observed by the naked eye after laser interaction due to its high strength. Furthermore, the chemical analysis indicates that chemical composition changes were caused by various mechanisms including dehydration of calcium hydroxide and thermal decomposition of calcium carbonate.