Coral reefs occupy only a tiny fraction of the ocean floor, yet they are home to a quarter of all marine species. While they’re delicate and increasingly at risk due to climate change, could they also provide inspiration for how we build our own habitats on land? For the fifth edition of the Chicago Architecture Biennial, Skidmore, Owings & Merrill (SOM) designed a spiral-shaped pavilion that introduced an entirely new construction material: the Bio-Block. Developed by Colorado firm Prometheus Materials, the concrete block alternative harnesses microalgae, one of the many life forms that coral reefs support.
To produce Bio-Block, microalgae is grown in factory conditions with artificial sunlight and seawater — plus CO2 from ambient air — to support photosynthesis. Organic additives are mixed in to stimulate biomineralization, replicating the growth processes of coral and seashells. The plant is then dried out, ground to a powder and blended with natural binders to form a bio-cement. From there, it is mixed with aggregate to become bio-concrete. Pressed into shape, it is finally left to dry, and 95 per cent of its water returns to the atmosphere.
Once the curing process is completed, the next challenge is making sure that the structural units get put to good use. Scott Duncan, the SOM design partner behind the pavilion, explains that the primary benefit of Bio-Block is that it is a “frictionless solution,” integrating seamlessly into existing construction practices. Indeed, skilled union masons provided feedback as they built the Spiral Pavilion, a project that would have resulted in over a metric ton of additional carbon emissions had it been formed using traditional concrete.
“We can’t get to net zero without changing our use of cement and concrete,” says Loren Burnett, president, CEO and co-founder of Prometheus Materials. He hopes their products, if deployed at scale, will help the construction sector reduce climate emissions by eight per cent; his company has already received US$8 million in series A funding, including from SOM. And Burnett envisions many other uses for his cement alternative: Bio-Block is one of five initial products in a range that also includes acoustic panels and paving. A ready-mix cement will be available soon, and reinforced panels might be possible further down the line.
Prometheus Materials is now undertaking a round of funding to build a factory to expand production and research such applications. When it comes to the building materials of tomorrow, the tides are turning.
Prometheus Materials previews the next wave of construction with a masonry block made of algae.