Unveiling Bloom, the Largest Powder-Based 3D Printed Structure

On March 6, 2015, I watched University of California Berkeley, with support from Oakland-based Emerging Objects and Siam Research and Innovation Ltd., unveil the largest structure ever printed with a powder based 3D printer. Aptly named Bloom, the structure stands 9 feet high, 12 feet wide, and is made of 840 8” x 8” 3D-printed blocks bolted together. Bloom is a work of art, but it’s much more than that. It represents a fundamentally new way of building, and if it catches on, the technology behind Bloom could make 3D printers as common at construction sites as hard hats and caution signs.

Bloom 3D printed concrete structure from emerging objects
Photo by Matthew Millman Photography, via Emerging Objects.

Bloom is a milestone in the development of architecture comparable to the first steel-reinforced concrete building. The structure’s construction technique combines new materials, new building processes, new design philosophies, and off-the-shelf 3D printers to print structures that are cheaper, more functional, and much more imaginative than anything ever possible before. For those familiar with Emerging Objects, that’s not much of a surprise.

Bloom 3D printed structure outside closeupHeaded by Berkeley Associate Professor Ronald Rael, Emerging Objects has been dazzling attendees at Maker Faires for years with some of the most beautiful, complex, and absolutely unique objects ever made by any production method. The materials their works are made of are as remarkable as the works themselves: salt, paper, chocolate, nylon, acrylic, wood, and cement polymer. However, no matter what the material, their work always has a mathematical quality to it that makes you feel like, somehow, you’re looking at nature’s most secret source code, somehow captured and displayed. (You can see their work online at their website, or at Shapeways, for downloading or printing & shipping.) They initially made household items, but they have since decided to move on to more ambitious projects.

About a year ago Rael, heading up a UC Berkeley research team, and Siam Research and Innovation began collaborating to develop the technology we now see in Bloom. The key was the formula of the concrete. The concrete Bloom is made from is different than most concrete, which is a combination comprised mostly of rocks and some Portland cement. Bloom’s concrete is even different from the leading polymer-related concretes, polymer concrete and polymer-modified concrete. Polymer concrete simply replaces Portland cement in the mix with a polymer binding material. Polymer-modified concrete is the usual mix of Portland cement and rocks, but with some extra polymers added to fine-tune its characteristics. Both need to be wet in order to harden, and are usually cast in large, heavy panels requiring machinery or significant labor to install or place onsite. Professor Rael’s approach is very different.

The Emerging Objects 3D printing Lab at Berkeley
The College of Environmental Design Lab.

First, Professor Rael decided it would be better to print a greater number of smaller pieces than fewer larger pieces. As a result, every part of Bloom was designed to have a maximum print size of 8 x 8 x 4 inches. This allowed Bloom to be printed by a farm of 11 3D Systems printers located in the College of Environmental Design and at Emerging Objects’ shop in Oakland. Second, Professor decided to develop his own concrete formula. No small task. People have been developing and improving cement since Roman times. The cement we use today is very strong and cheap to make.

I asked Professor Rael how his cement formula compared with traditional concrete. He told me that his cement has a compressive strength of 4,700 psi. In comparison, the compressive strength for the concrete usually used for building homes is rated at 2,500 psi, and concrete for commercial buildings can range up to 4,000 psi.

He said, “While there are a handful of people currently experimenting with printing 3D architecture, only a few are looking at printing with cement-based materials, and all are extruding wet cement through a nozzle to produce rough panels.”

“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. This project is the genesis of a realistic, marketable process with the potential to transform the way we think about building a structure.”

Professor Rael estimated the material Bloom was built with to cost about $60 per 100 pounds, and that the entire structure weighed about 2,000 pounds, for a total cost in materials of $1200. With a little modification Bloom could have been altered to form a 12-foot dome with a closed roof for about the same amount of material and cost.

bloom 3D printed block showing numberLabor wasn’t much of an expense. Bloom can be assembled and disassembled by a handful of people in a couple of hours. They don’t need to have detailed assembly instructions. They don’t even have to know what it looks like when it’s assembled. Every part ID on the inside of a component describes in what column and at what level the part should go. And the construction is really easy. There’s no building frame supporting Bloom’s walls; the curves of the walls provide all the support they need. It’s a new kind of architecture, and it’s about time.

How realistic are Emerging Objects hopes? For their technology to take off, 3D printers from 3D Systems and other manufacturers are going to have to print Professor Rael’s magic concrete a lot faster than they do now. In 3D Systems case, there’s a good chance they might.

Professor Rael has been working on printer issues with the Chief Marketing Officer at 3D Systems, Cathy Lewis, which is very fortunate. Cathy Lewis pioneered low-cost 3D printing while CEO at Desktop Factory, and is arguably the most competent CEO any 3D printer company has ever had. She’s probably the best-equipped person in the industry to justify and get the kind of budget and resources needed to develop the kind of 3D printers we need now. It won’t be easy, but it will be worth the risk.

The commercial potential of this technology goes off the charts. Within a few years we could have flexible concrete, sound absorbing concrete, super strong concrete, super light weight concrete, completely recyclable concrete, any combination of the above, or even more. It will even be possible to print individual building parts out of several types of cement at once. For instance, it would be possible to print a building support column with concrete that was extremely strong in the center but flexible and sound absorbing on the outer edges.

Bloom 3D printed structure from emerging objects made from concrete polymer
Photo by Matthew Millman Photography, via Emerging Objects.

Bloom’s technology could also help us recover from natural disasters. In the case of a Katrina-level event, millions of tons of 3D printed debris could be recycled and used to rebuild the city, instead of becoming just a huge trash pile to get rid of.

Bloom presents so many potential uses it’s hard to evaluate them all properly. I had a chance to ask the senior executives of SRI what they planned to do with their new technology in the immediate future. They told me that, in the immediate future, the company will return to Thailand with Bloom, and begin the first of many promotional tours across Asia with the structure.

They added that their main focus will be on mainstream construction. They want to make the world’s most advanced concrete, not really develop a new housing construction process. At least for now, the President of SRI told me, they consider 3D printed housing too expensive for general use.

Still, the potential of Bloom’s technology is too great to ignore. We’ve made a lot of progress in cement technology in the past few centuries, but it should be remembered that after nearly 2,000 years, we still have yet to match, let alone surpass, the Roman Parthenon. It’s still the biggest free-standing concrete dome in the world. UC Berkeley and Emerging Objects’ technology doesn’t promise anything on the scale of the Parthenon, but it might offer buildings just as wondrous, and far more profitable. We should make sure that the team behind Bloom has a chance to do so.

Correction 3/10/2015: This post previously attributed Emerging Objects as the creator of this project.  Though Prof. Rael is a leader of the Oakland studio, the project was the result of research at the University of California Berkeley.