My primary research interest is Laser Aided Manufacturing (LAM) on composite materials. My recent research focuses on the applicability of laser processing to composite materials such as concrete and rock. I am investigating 1) the mechanism of the composite materials through the interaction of the composite material and the laser, 2) the physical and chemical changes of the composites during laser-composite interaction.
Cement-based materials are prevalent materials in almost all construction fields, such as buildings, roads, bridges, dams and nuclear power plants. The cement-based materials can be deteriorated under some unfavorable circumstances, such as high chloride environments, poorly controlled concrete casting and unexpected overloading. For this reason, the demand for the removal of deteriorated parts is steadily increasing. Conventional cutting methods for cement-based materials are typically used diamond saw cutting, wire cutting, and water-jetting. However, these methods are time consuming and uncertain removal due to relatively low precision. In addition, undesirable vibration could cause micro-cracks in the sound concrete structure, which could lead to the removal of essential cement-based materials sections. Furthermore, there are additional drawbacks, including noise and dust generation during the cement-based materials removing process. On the other hand, Laser-Aided Manufacturing (LAM) has many advantages, such as no tool wear due to no physical contact, low Heat-Affected Zone (HAZ), high precision, high energy density, low noise level, flexible processing, high productivity and high processing speed. Based on these advantages, laser scabbling has been studied to remove the surface material of concrete using a high-power laser beam. However, this process is only limited to the removal of surface layers. To remove more volume of concrete, a higher laser beam energy is required. Recently, since a high-power laser beam of 10 kW is commercially available and can be focused on very small spots up to 10 um by manipulating the optics, laser cutting can be applied to remove the large volumes of cement-based materials. In addition, laser ablation techniques are considered as the alternative technology to remove the contaminated concrete of about 76.2 mm thickness in nuclear power plants. By decontaminating the concrete surface using the laser ablation technique, the generation of radioactive concrete waste can be significantly reduced.
