It seemed unbelievable when, in 2014, a Chinese construction company called WinSun unveiled 10 concrete houses that had supposedly been 3D printed in under 24 hours. Since then, however, the field of 3D-printed construction has slowly started to grow, recently culminating in the world’s first 3D-printed public building in the United Arab Emirates.
While the walls for WinSun’s projects are 3D printed offsite with a yet unseen concrete 3D printing system, the results, including a five-story apartment building, are often quite impressive. Now, another Chinese company has come onto the scene, this time performing the 3D printing process live and onsite.
The villa 3D printed onsite. (Image courtesy of Huashang Tengda.)
Over the course of 45 days, Chinese construction company Huashang Tengda 3D printed a 400-square-meter villa. The structure features walls that are 250 mm thick and made up of roughly 20 tons of C30-grade concrete, which is typically used to lay pavement.
There have been numerous construction 3D printing projects that explore the potential of the technology for building unique structures quickly and with a limited amount of labor. For instance, Oak Ridge National Laboratory recently 3D printed a dwelling meant to share power with a 3D-printed biodiesel vehicle. An engineer in Minnesota also 3D printed his own castle in his backyard using a homemade concrete 3D printer before taking his business to the Philippines to 3D print a hotel.
The components were laid down before 3D printing was performed. (Image courtesy of Huashang Tengda.)
This may be the first instance of a building being 3D printed onsite and, more importantly, with structural and plumbing elements directly integrated into the 3D-printed elements. The video below shows a construction team monitoring and aiding the 3D printer as it pours concrete on top of a prelaid foundation that already includes all of the steel rebars and plastic pipes that will be incorporated into the final structure.
Behrokh Khoshnevis, seen as one of the pioneers of 3D-printed construction, has envisioned numerous machine and process configurations for 3D printing buildings, some of which include the automated placement of such elements into the walls as they are printed. Huashang Tengda, however, has chosen to create these elements first and then print over them.
Concrete is laid over the rebars and piping. (Image courtesy of Huashang Tengda.)
The firm described the way that this technology was made in-house and includes custom software, saying, “Our house 3D printing equipment combines four separate systems: an electronic ingredient formulation system, a concrete mixing system, a transmission system and a 3D printing system. We have used a traditional reinforced concrete material to 3D print the villa, without any additives. The material does not need to be specially customized, so users can simply use locally produced cement to greatly reduce material transportation costs.”
Manual labor is still required. (Image courtesy of Huashang Tengda.)
The benefits of this construction technique, according to the company, is the speed, efficiency and cost of 3D printing over traditional construction methods. Unlike other cement printing processes, which often use quick-drying material concoctions, the company claims to use standard concrete, thus bringing down material costs. At the same time, only the needed material is used, reducing overall waste. Additionally, the firm suggests that a similarly sized structure would have taken three months to construct—its villa was printed in only 45 days. Buildings could also potentially be made in more elaborate shapes more easily than is possible with typical fabrication techniques.
Khoshnevis previously predicted that 3D printing in construction would see widespread usage by 2020 and that high rises would be 3D printed by 2025. As Singapore already aims to 3D print skyscrapers for its public housing program and Dubai plans to 3D print 25 percent of its buildings by 2030, the University of Southern California professor may very well be right. Unfortunately for Khoshnevis, some of this may occur without his credit as he has also accused WinSun of stealing the designs for his concrete 3D printing technology.