Berkeley researchers pioneer new powder-based concrete 3D printing technique
3D printing looks set to become very important in architecture, but we've yet to see exactly how the future of large-scale click-and-print construction will play out. A potential step forward comes via a team of UC Berkeley researchers led by Associate Professor of Architecture Ronald Rael, who recently created a free-standing pavilion called Bloom to demonstrate the precision of their powder-based cement method of 3D-printed construction.
We've previously reported on several 3D-printed architecture projects, including Andrey Rudenko's castle and Winsun's impressive feat of printing 10 houses in less than 24 hours. However, the method pioneered at Berkeley by Rael and his team is different to those, and rather than extruding wet cement, involves printing out thin layers of a special dry cement powder, each of which is then sprayed with water to harden the structure.
"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," says Rael, who is also a member of Emerging Objects, the group behind the Cool Bricks concept we recently covered.
So what's the benefit of this system over existing methods of extrusion? Well, using an iron oxide-free Portland cement polymer formulation developed by the team members, along with their system of 11 powder-based 3D printers, they can create a more complex and precisely finished structure than the extrusion method, and one which is reduced in weight and waste.
"We are mixing polymers with cement and fibers to produce very strong, lightweight, high-resolution parts on readily available equipment; It’s a very precise, yet frugal technique," adds Rael. "This project is the genesis of a realistic, marketable process with the potential to transform the way we think about building a structure."
To demonstrate this, the team produced the Bloom pavilion, which rises to a height of 2.7 m (9 ft) in height, has a footprint of roughly 3.6 x 3.6 m (12 x 12 ft), and is built using a total of 840 customized blocks connected with steel hardware. Its unusual appearance is partly due to the removal of the iron oxide, which is what gives cement its usual color, according to Rael. Each brick is unique, and creates a complex decorative pattern that lets some light pass through.
Rael told Gizmag that the current system of 11 printers could construct up to 30 blocks per day – which could potentially produce the Bloom pavilion in a total of 28 days. However, the actual project took around a year, including designing the parts, testing, building the printers, repairs and refinements, and the actual printing process.
Bloom is currently on display in Berkeley and will be disassembled and shipped to SRI in Thailand (the research and development division of Siam Cement Group, who provided financial backing and support for the research), where it will be exhibited and remain on display before visiting select locations worldwide.