Laser based hybrid technique for civil engineering

A laser-based hybrid technique is shown to be effective for cutting concrete and drilling rock. Experimental conditions used included a laser power of 1-10 kW, 10 mm laser beam diameter and 1.25-50 mm/s scanning speed. The results of surface scanning tests and 100 mm deep cut tests indicated that the shortest operation time was about 3.5 hr/m2 for plain concrete and 4.5 hr/m2 for heavy concrete. The specific energy for the rocks (the amount of energy required to remove a unit volume of rock), which were granite and sandstone, was as same as that for heavy concrete. Thermal decomposition was observed for limestone. The specific energy of limestone was more than 1.5 times higher than that for granite and sandstone.