Kanto Regional Development Bureau / Producing revetment blocks with 3D printers / Trial introduction for construction of Arakawa No. 2 Regulating Reservoir
17 November 2025 – Technology & Products
The 3D printer introduced on a trial basis (blocks produced in the foreground)
The Kanto Regional Development Bureau of Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is trialling the use of 3D printers to produce revetment blocks for the ongoing construction of the “Arakawa No. 2 Regulating Reservoir” in Saitama Prefecture. The target application is the curved sections of the revetment near the drainage gate of the reservoir, where conventional processing is difficult. Because the printer can shape blocks exactly according to design drawings, it is expected to reduce labor requirements and decrease hazardous manual work.
The blocks produced by the 3D printer will be installed near the inner waterway of the drainage gate area within the reservoir, a section for which the Kanto Regional Development Bureau has issued the construction order. The construction is being carried out by Tobishima Corporation. Polyuse (Minato-ku, Tokyo; represented by Takuya Iwamoto and Wataru Ooka), a company specializing in construction 3D printers and related technologies, is supplying the equipment. Of the entire revetment area (approximately 600 square meters), around 72 square meters will be produced using automated 3D printing.
The printer measures 3.7 meters wide, 3.4 meters long, and 2.8 meters tall. The curved revetment blocks range between 0.7 and 1.8 meters in width and are 1 meter high. With a thickness of 16 centimeters, the printer can produce about four blocks per day. The printer reads 3D CAD data and extrudes a mortar-and-water mixture through a nozzle to create formwork. Fresh concrete is then poured into the hollow shapes to complete the blocks. The two materials used for the formwork are uniquely formulated by Polyuse and can be adjusted according to site conditions.
The revetment features subtle curves in various places. Previously, workers manually shaped the blocks to match the design using rotary tools. This process required significant effort and posed risks of injury due to tool usage. Takushige Yonezawa, Director of the Arakawa Regulating Reservoir Construction Office at the Kanto Regional Development Bureau, described the 3D printer as “a new tool that contributes to labor savings.”
The actual machine was demonstrated on the 14th for personnel from MLIT and Saitama Prefecture, and on the 15th during a parent–child site tour hosted by the Kanto Branch of the Japan Society of Civil Engineers (chaired by Tomohiro Sugiyama).
