WEDNESDAY, MAY 25, 2022
Cornell University in Ithaca, New York, recently announced that it is now home to a 6,000-pound robot with 3D printing capabilities, with a goal of potentially making the construction industry more efficient and sustainable. The IRB 6650S Industrial Robot system arrived at the Bovay Civil Infrastructure Laboratory Complex in February, reportedly making Cornell one of only a handful of universities in the country to have such a system.
According to Derek Warner, professor of civil and environmental engineering, not only will it enable College of Engineering faculty to do robotic construction research, it will also give students hands-on experience in the fast-growing technological area within civil infrastructure.
“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,” Warner said.
“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.”
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| Photos: Cornell University, Charissa King-O'Brien |
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Cornell University in Ithaca, New York, recently announced that it is now home to a 6,000-pound robot with 3D printing capabilities, with a goal of potentially making the construction industry more efficient and sustainable. |
For the last several months, the university reports, the lab has being training to use the robotic system that comprises of a long, swiveling arm, and has run a number of medium-size test prints. The prints have included benches, planters and a large letter C in the Cornell typeface.
According to the release, the robot is set on a 12-foot-long track, with a circular reach of about 12 feet, for a total coverage area of up to 8 feet by 30 feet. However, James Strait, manager of tech services for Bovay Lab, said that he doesn’t anticipate anything quite that large.
The system operation requires a team effort, with one group mixing pre-batched mortar and stirring in additives, while the other operates the robot’s controller to regulate how much admixture runs through the system.
Superplasticizer can be added to reduce the water content of the mix and improves its flow through the hose. A hardening additive is introduced when the admixture reaches the extruder head and nozzle, thickening the material as it is poured.
“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,” Strait said. “You need to make the adhesion in there, but you can’t have it so soft that it squishes out.”
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For the last several months, the university reports, the lab has being training to use the robotic system that comprises of a long, swiveling arm, and has run a number of medium-size test prints. |
Despite the process being labor intensive, 3D printing reportedly eliminates the need for cast molds, thus also allowing for the creation of unconventional shapes which can waste less material.
“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,” Strait said.
“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.”
Currently, the system is 3D printing with mortar that has an aggregate up to four millimeters in size. Cornell reports that anything larger would jam and damage the pump system.
“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.”
Nair reportedly plans to incorporate the system into a new class this fall, Sustainability and Automation: The Future of Construction Industry.
“We are giving them an opportunity to learn something that’s cutting edge and happening right now,” Nair said. “The more they know, the more they can be champions of change, but also know what the limitations could be.”
Nair’s team also anticipates building their own extruder head to print steel-fiber-reinforced concrete, using larger aggregates that can withstand heavier loads. Eventually, the university reports, this could pave the way for the lab to 3D print full bridge components for testing.
Additionally, Nair hopes to create a mixture to print with, rather than relying on the manufacturer’s premixed material.
“The carbon footprint of these materials is very high right now,” she said. “So that’s another goal, to reduce the carbon footprint associated with 3D-printed materials.”
Recent 3D-Printed Infrastructure
Last year, students from the Rhode Island School of Design presented a virtual exhibit reimagining pedestrian and cyclist access on the Newport Pell Bridge.
Unlike other replacement, rehabilitation or new construction bridge projects now accommodating for pedestrians and cyclists in the form of specified lanes, students have looked to how these types of access lanes could be installed beneath these massive structures.
“It’s not super easy to get to Newport unless you have a car,” says Liliane Wong, a professor of interior architecture at Rhode Island School of Design who led a class in adaptive reuse that considered how it might be possible to redesign the bridge.
However, adding another deck onto an aging piece of infrastructure isn’t easy, and in most cases, can’t support the additional weight. To mitigate these potential issues, students from Wong’s class developed the idea of 3D printing these new lanes from carbon fiber wrapped with a composite membrane, a material that’s both lightweight and strong.
According to the students, the deck would attach to the bridge’s existing columns. In addition, since the Newport Pell Bridge had been their structure focus, the students also considered the comfortability of those crossing the 2.1-mile-long structure. As a result, the students also included sheltered spaces for restaurants, small shops, dog parks and other activities in their designs.
At the beginning of the year, a team of researchers from public research university, ETH Zurich, were reported to successfully create a pre-cast concrete slab using 3D-printed formwork elements made from recyclable mineral foam.
In using 70% less material than traditional concrete slabs, the team found that FoamWork, their newly developed building material, is both lighter and better insulated. The slab mold prototype used for the research was reportedly filled with 24 mineral formwork elements in 12 different shapes and sizes before concrete was cast around the material to cure.
The framework uses a 3D printer and autonomous robotic arm to print the mineral foam before being placed into a conventional timber perimeter formwork. The material itself is created by foaming cement. As a result, hollow cells are created throughout the panel.
To optimize the material’s strength and insulating materials, the team reinforced the material’s internal geometry—particularly along its stress lines—to achieve both goals, in addition to drastically reducing the amount of concrete needed to produce the slab. However, the shape and configuration of the internal cells could be customized in order to create a range of concrete building elements, such as walls or roofs.
Most recently, reports indicated that China is preparing to build a hydropower dam by 2024 using an artificial intelligence system, robots and 3D printing. The South China Morning Post reports that the 590-foot-tall dam will be fully automated and will not require human workers, eliminating the risk for human error and safety concerns for workers.
Once completed, the project is expected to generate almost 5 billion kilowatt-hours of electricity each year to the Henan province. The project is expected to be the world’s tallest structure using 3D printing if and when it is completed.
Scientists involved in the project said that the Yangqu dam on the Tibetan Plateau will be assembled layer by layer, using a 3D printing method from an article published last month in the Journal of Tsinghua University (Science and Technology). The system uses intelligence robots and a construction scheduling system for the efficient filling of large construction projects.
A 3D scheduling system cuts the 3D digital design model into slices to calculate the filling material information, then it plans the transport roads on the site map model for each step in the construction process, according to the paper.
For the dam construction, a central AI system will reportedly be used to oversee the automated assembly line that starts with a fleet of unmanned trucks used to transport construction materials to parts of the worksite. Automated bulldozers and pavers will then use those materials to turn them into a layer of the dam.
Next, rollers equipped with sensors will press each layer to become firm and durable. Once a layer is complete, robots will send information about the state of the construction back to the AI system.
Tagged categories: 3D Printing; Additives; Building materials; Colleges and Universities; Green Infrastructure; Infrastructure; Infrastructure; Mortars; Program/Project Management; Research and development; Robotics; Sustainability; Technology; Tools & Equipment
