An interdisciplinary team at Penn State University was recently awarded a $50,000 grant from the College of Engineering’s Engineering for Innovation and Entrepreneurship (ENGINE) program, along with additional $25,000 from the College of Arts and Architecture, to pursue a concrete 3D printing project.
The team—made up of faculty from the Departments of Architecture, Architectural Engineering, Civil and Environmental Engineering and the School of Engineering Design, Technology and Profession Programs—believes that construction 3D printing has the potential to radically transform the construction industry for the better of the planet.
Today, construction is one of the most taxing industries on the environment, contributing significantly to air pollution, water pollution, waste and more. It is no surprise then that significant resources and research efforts are being put towards developing more eco-friendly solutions for the construction sector. After all, it is not in human nature to stop building, so the ways of building will have to change.
In recent years, 3D printing has presented a possible avenue forward. By 3D printing concrete structures, buildings could be made on-site and with far less material waste, reducing fuel from transportation and overall waste.
An alternative to cement
At Penn State, the interdisciplinary team’s work began during the 3D Printed Habitat Challenge, in which NASA invited groups to submit designs and 3D printing solutions for astronaut habitats in space. The group developed a particularly interesting material solution, called MarsCrete, which is a cement-free concrete. The recent funding will enable the team to build upon this research to commercialize the material and 3D printing technology.
Traditional concrete is made up primarily of ordinary Portland cement (OPC), water, sand and aggregates. OPC, however, requires extensive energy to produce and emits significant carbon dioxide (about one ton of carbon dioxide per ton of OPC made). The cement industry is responsible for about 5% of the carbon dioxide emissions we create.
Moving ahead with MarsCrete
The research team, led by Ali Memari, the Bernard and Henrietta Hankin Chair of Residential Construction and professor of architectural engineering and civil engineering, will expand upon its cement-free MarsCrete material by creating high-performance, sustainable concrete made up of a cement-based mixture. The new material will be developed specifically for home building and small building construction.
The $500,000 ENGINE grant will enable the researchers to complete proof-of-concept testing for the new material and explore some innovative reinforcement concepts.
Also crucial to the researchers’ work is a 3D printer made up of a dual mixer and pump that feeds a nozzle controlled by a six-axis robotic arm. The system was devised for the NASA 3D Printed Habitat Challenge and has performed well for the past two years.
“The concrete formulations and the printer system are tightly coupled, as the design of one affects the design of the other,” said Sven Bilén, head of the School of Engineering Design, Technology, and Professional Programs. “We have to work from the micro-scale to the macro-scale. Our work is also tightly coupled to the architectural designs that can be realized via our materials and printing methods. All three—materials, printing system and architecture — must be considered together.”
A multidisciplinary approach
The project aims to 3D print sample buildings using its 3D printing technology and material to demonstrate the benefits of the process, including reduced material waste, faster construction times, less labor and lower costs. However, Memari does emphasize that the 3D printing approach will unlikely replace traditional construction methods.
“The technology for 3D printing of concrete is not being developed to replace conventional construction that can be carried out economically with existing methods,” Memari said. “Rather, this technology will be more useful for complex designs, where conventional methods of using formwork will be much more expensive or prohibitive.”
Ultimately, the multidisciplinary team hopes to better understand the various components of construction additive manufacturing—material mixture, material characterization and design and the printing process itself.
“The development of 3D printing technology at the construction scale is a complex endeavor,” added José Pinto Duarté, faculty member of the College of Arts and Architecture. “Given the breadth and depth of the knowledge required, it would be rather difficult for a single investigator to perform meaningful research at a reasonable pace in this area. Multidisciplinary collaboration among researchers with different, complementary expertise is, therefore, essential. Penn State has a system of incentives in place that fosters multidisciplinary collaboration and the development of research like ours.”