In the basement of Thurston Hall, the Bovay Civil Infrastructure Laboratory Complex has installed a formidable new research tool: a 6,000-pound industrial robot designed for large-scale 3D printing. This system, an IRB 6650S Industrial Robot, is poised to explore how additive manufacturing can reshape construction practices by reducing waste and enabling complex geometries that traditional methods struggle to achieve.
Additive manufacturing has already transformed sectors such as prototyping and biomedicine, but its application to civil infrastructure raises critical questions about performance at scale. The Bovay Lab’s testing capabilities—covering materials and structures of varied sizes—position it to address these questions through rigorous mechanical and structural evaluation. Cornell now joins a small group of U.S. universities equipped for such research, providing both faculty and students with direct access to robotic construction technologies.
Derek Warner, professor of civil and environmental engineering, emphasized the breadth of opportunities: “Robotic masonry (brick laying), printing with recycled plastics and printing with metal at a large scale are all exciting areas with lots of room for growth, both in terms of science and understanding, as well as technology and engineering. The scaling of many of the phenomena controlling the build processes are such that they need to be studied at a scale near to that in which they will be used. The same applies to some of the phenomena controlling performance. Plus, there are always the unknown surprises that occur when up-scaling early-on with a new technology.”
Since its arrival in February, the robot has completed medium-scale test prints—benches, planters, and even a large Cornell “C.” Its core design features a long, swiveling arm mounted on a 12-foot track, offering a circular reach of roughly 12 feet and a total coverage area of up to 8 by 30 feet. While the lab does not anticipate printing at maximum dimensions immediately, the system’s versatility is already being explored.
“The robotic system is versatile and flexible,” said Sriramya Nair, assistant professor of civil and environmental engineering. “One of the ways we are using it is for 3D-printing of concrete, but it can be used in other ways, too. You can attach a welder or laser system. You can stack bricks or tie rebar. Many tedious processes can be automated.”
Operation involves coordinated teams. One group prepares pre-batched mortar, incorporating additives such as superplasticizers to improve flow through the delivery hose. Another team controls the robot’s extrusion parameters. At the nozzle, a hardening agent is introduced to ensure the material gains strength as it is deposited. Achieving the right consistency is critical. James Strait, manager of tech services for the Bovay Lab, described the challenge: “The bottom layers need to be rigid enough to hold the next layer that’s being printed. But they can’t be so rigid that when you print the next layer on top, it doesn’t stick to it. You need to make the adhesion in there, but you can’t have it so soft that it squishes out.”
When executed correctly, the process bypasses the need for casting molds, saving time and materials. Strait noted the efficiency gains: “Any time you pour cast-concrete, like for a sidewalk, you have to set up all the molds. It takes labor, materials, you have to stake it all down. All of that stuff takes a lot of time. Every change you make to a concrete structure, you have to modify the mold or get a new mold and spend labor doing that. That is a lot more difficult than going to a computer program and saying, ‘You want this rounded?’ Click. A couple of hours and you’re done.”
Nair plans to integrate the robot into her upcoming course, *Sustainability and Automation: The Future of Construction Industry*, giving students exposure to cutting-edge tools and methods. “We are giving them an opportunity to learn something that’s cutting edge and happening right now,” she said. “The more they know, the more they can be champions of change, but also know what the limitations could be.”
Currently, the system prints with mortar containing aggregate up to 4 millimeters, as larger particles risk damaging the pump. Nair’s team aims to develop a custom extruder head for steel-fiber-reinforced concrete, enabling components capable of bearing heavier loads, such as bridge segments. Another goal is to formulate proprietary mixtures with reduced carbon footprints. “The carbon footprint of these materials is very high right now,” Nair said. “So that’s another goal, to reduce the carbon footprint associated with 3D-printed materials.”