4 Exciting New Possibilities for Concrete

Biocement Made from Bacteria

A collaboration between North Carolina–based Biomason and Copenhagen, Denmark, architecture firm 3XN’s research studio, known as GXN, this product uses Biomason’s proprietary Biocement, which uses non-modified bacteria to grow a cementlike material that is 20 percent lighter than concrete blocks, yet three times stronger. Introduced at the Copenhagen Contemporary Museum’s 2023 exhibit Reset Materials — Towards Sustainable Architecture, the collaborators created an architectural column grown from bacteria with minimal human intervention in just 72 hours. The process requires significantly less energy than manufacturing cement and can make use of natural aggregates (sand, soil) or recycled concrete, brick, and glass.

“We’ve been looking at Biocement for more than ten years, but it’s not been at a stage where people were interested in investing, or in bringing it up to a scale for the built environment,” says architect Lasse Lind, a partner and head of consultancy at GXN. “Whereas now we’ve arrived at a moment in time where that’s changing. It’s dawning on a lot of people that we actually have to change.”

Brimstone’s Carbon-free Cement

Instead of baking limestone to make Portland cement, Oakland, California–based Brimstone uses carbon-free calcium silicate rock to make its cement, which does not release carbon dioxide. Brimstone’s is the first product to receive third-party certification from the international standards organization ASTM International, proving it meets the same specification guidelines as traditional cement.

“Massive industrial change typically only happens when technical advances or economic shifts make a new product cheaper or more efficient,” says Brimstone CEO and cofounder Cody Finke. “In some places, supplementary cementitious materials are also becoming scarce, leading to high prices and creating co-product markets. Because of the rising price of co-products like SCM and other market conditions incentivizing low-carbon innovation, our idea is only recently economically sound—and we were lucky to think of it first. Brimstone’s deeply decarbonized process is more efficient and lower cost at scale than the status quo.” 

3-D Printed Recycled Cement at Holcim

After first building the temporary Striatus bridge at the 2021 Venice Architecture Biennale using 3D-printed concrete blocks assembled without mortar or steel reinforcement, collaborators Zaha Hadid Architects, manufacturer Holcim, and the Block Research Group at Swiss research university ETH Zurich have created a follow-up, the Phoenix bridge, at Holcim’s Lyon, France. Made partly by recycling material from the Striatus, Phoenix contains 40 percent less embodied CO2, reducing its carbon footprint by 25 percent compared with reinforced concrete structures. Phoenix demonstrates a circular system allowing Holcim to upcycle 100 percent of demolition materials into new building solutions, from aggregates and sand to decarbonized cement paste.

Whereas Striatus is temporary, “Phoenix will stay in place, and we want to use the service life here within our premises to monitor how it evolves,” says Hélène Lombois-Burger, Holcim’s head of research and development for concrete and aggregates and digital fabrication. Utilizing 3D printing, she adds, allows greater precision. “You are saving up to one-third of the concrete and one-half of the steel versus a conventional reinforced bridge.”

Prometheus and SOM Unveil Bio-Block

Concrete blocks are one of the industry’s most ubiquitous products, as common to Home Depot aisles as to large-scale building projects. Boulder, Colorado’s Prometheus Materials recently collaborated with Chicago-based mega-firm Skidmore, Owings & Merrill at the Chicago Architecture Biennial to introduce the zero-carbon Bio-Block—made primarily from algae-based bio-concrete—at a public installation called Bio-Block Spiral. Constructed by skilled local masons, it is another step in making this alternative product mainstream.

“We saw the promise in it, which is easy to do,” says SOM design partner Scott Duncan, who sees potential for the firm’s skyscraper projects. “Bio-Block dampens sound more than CMU [concrete masonry units], and it’s lighter. When that gets used over dozens of floors, it has an accumulated positive effect on everything else. Your beams can be lighter, your foundations can be smaller. That has a collateral impact on foundations and overall structural frame sizes.” 

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• Architecture
• Sustainability
• Technology

• 3XN
• Bio-based Materials
• biobased materials
• Biomason
• Brian Libby
• Brimstone
• Cement
• Concrete
• Construction Materials
• Holcim
• Prometheus
• SOM
• Zaha Hadid Architects