Researchers from the University of Berkeley in California are pushing the boundaries of 3D printing for building and construction purposes with the development of a new cement powder material that will permit the creation of more daring and innovative structures.
Major strides have been made in recent years in the usage of additive manufacturing for building construction purposes – most notably by Chinese 3D printing company WinSun, which has grabbed headlines around the world with its attempts to create homes, villas and apartment buildings with record-breaking speed.
All of these techniques, however, have relied on the same conventional method of additive manufacturing – the application of a voluble building material in successive layers to produce a finished solid object to the desired specifications.
Now, a team led by Ronald Rael, associate professor of Architecture at UC Berkeley, could be the first to experiment with a different method the 3D printing of buildings. This development could dramatically expand the potential for the technology for construction and architectural purposes.
“While there are a handful of people currently experimenting with printing 3D architecture, only a few are looking at 3D printing with cement-based materials, and all are extruding wet cement through a nozzle to produce rough panels,” said Rael.
Instead of pouring out a liquid building material in layers, the new system developed by Rael and his colleagues at UC Berkeley’s Emerging Objects involves the printing of thin layers of a special dry cement powder to produce precisely customized blocks.
Water is then applied to the printed blocks in order to bind the powder together and harden it.
According to Rael, the new material the team has developed is an iron-oxide free Portland cement polymer that results in printed structures which are far lighter and more precise than those currently being produced by their peers using conventional additive manufacturing techniques.
“We are mixing polymers with cement and fibres to produce very lightweight, high-resolution parts on readily available equipment; it’s a very precise, yet frugal technique,” said Rael.
In order to demonstrate the increased precision and flexibility of design that can be achieved using the 3D printing powder, Emerging Objects created the Bloom Pavilion on the university campus – a highly intricate, curvilinear structure whose creation would defy the capabilities of other existing forms of 3D printing based construction.
The pavilion stands a total of 2.7 metres in height while covering an area of approximately 3.6 by 3.6 metres. It was built using a set of 840 individually customized blocks, each of which possesses an intricate decorative pattern that permits the passage of light.
The blocks are connected together using steel components, while the absence of iron oxide from the cement powder confers it with a highly distinctive hue.
While the entire development process for the Bloom Pavilion took roughly a year, Rael said now that design and testing has been completed and the production process refined, a new pavilion could be created in under a month using the team's existing system of 11 printers with an output of 30 blocks a day.
The intricate and elaborate design of the Bloom Pavilion – which in addition to using individually customized bricks is characterized by a complex, curvilinear surface – serves as ample proof that 3D printing is up to the task of structurally challenging architectural projects.
The 3D printing of a dry powder enables the process to produce highly intricate and detailed features that could be beyond the capabilities of other forms of additive manufacturing in the building sector that use nozzle-dispensed wet materials. The fact that the powder is based on Portland Cement - one of the world's most widely employed building materials, also means that it's likely to be easy to source and cost-effective.
The current usage of the method of 3D printing employed by the developers of the Bloom Pavilion could be restricted in terms of convenience, however, by the comparatively small size of the bricks; the chief virtue of other additive manufacturing processes used for construction has been their ability to rapidly extrude sections of material in large-scale swathes.