Shimizu’s Spray-Based 3D Printing System Is Redefining How Reinforced Concrete Is Built

As Japan’s aging population and shrinking construction workforce put growing pressure on the industry, Shimizu Corporation is turning to a new kind of 3D printing. The company has developed a spray-based system designed to fabricate large, curved, and reinforced concrete components. Unlike extrusion-based printers, it sprays a special concrete mixture from a robotic nozzle instead of laying down stacked layers. This allows the robot to build shapes that would be difficult or impossible to achieve with conventional concrete printing.

This approach allows concrete to be deposited from multiple angles and around steel reinforcement cages. That is a major shift for structural construction, especially in seismic regions where reinforced concrete is essential. Most existing concrete printers struggle when rebars are present. Spray-based printing removes that constraint and makes true structural 3D printing possible.

How Simulation Improves Spray-Based Printing

Spraying concrete is powerful but unpredictable. Material can rebound, drip, or spread depending on nozzle distance, angle, and how fast it sets. To control this, Shimizu partnered with Carnegie Mellon University’s Computational Engineering and Robotics Lab to develop a material spray simulator.