Concrete Cutting by a Solid-State, Localized Microwave-Heating Applicator

This article presents experimental results of concrete cutting by a localized microwave-heating (LMH) applicator, fed by a 0.25-kW solid-state microwave generator. The LMH applicator is a modified microwave-drill, operating in a stepwise pecking mode. Compared to the previously-presented, magnetron-based microwave-drill for concrete, the new device operates at a lower power; it is more compact, and it enables arbitrary cutting contours. In each pecking step in this mode, a small amount of concrete is softened by LMH, and mechanically removed. These sequential pecks are accumulated to form a long deep groove along the desired cutting contour. The lower microwave power applied in the pecking mode enables a narrower LMH applicator, which reduces the total amount of concrete removed in the cutting process (the kerf), and hence improves the overall efficiency. The solid-state LMH pecking module can be remotely controlled, and it is applicable to other masonry as well. Its silent and clean operation (with no vibration or dust effusion) classifies it as an environmental-friendly technology. The article introduces the LMH pecking concept for concrete cutting, and presents its experimental results. Concrete removal rates of 0.35 cm3/min in 0.5-cm pecking steps (accumulated to 6-cm-long, 6-cm-deep grooves) were obtained by applying a 0.25-kW microwave power, in agreement with the LMH theory. The feasibility of a faster concrete cutting in practice by advanced LMH-based devices, also in array schemes, is discussed.