Biomimetic Materials

Life Lessons: Architects turn to biology for solutions to all that ails us.
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Architectural Record

Learning Objectives:

  1. Differentiate biomimicry from related concepts such as biophilia, biomorphism, and bio-utilization.
  2. Explain how biomimetic materials can sequester carbon.
  3. Discuss the role of additive manufacturing techniques in the fabrication of biomimetic materials.
  4. Describe biomimetic construction assemblies that can improve building performance and enhance occupant comfort.

Credits:

1 AIA LU/HSW
1 AIBD P-CE
0.1 IACET CEU*
AAA 1 Structured Learning Hour
AANB 1 Hour of Core Learning
AAPEI 1 Structured Learning Hour
SAA 1 Hour of Core Learning
MAA 1 Structured Learning Hour
NSAA 1 Hour of Core Learning
OAA 1 Learning Hour
NLAA 1 Hour of Core Learning
NWTAA 1 Structured Learning Hour
 
This course can be self-reported to the AIBC, as per their CE Guidelines.
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Approved for Core Learning
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This course is approved as a Core Course
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The earth’s biological materials and the processes through which they’re generated represent the fruits of about 3.8 billion years of research and development. As our species approaches the limits of the earth’s carrying capacity, there’s a lot humans can learn from them. That’s the basic premise of biomimicry—design inspired by the way functional challenges have been solved in biology.

PHOTOGRAPHY: © JOHN BRECHER FOR MICROSOFT

Jenny Sabin’s Ada, a digitally knitted enclosure, is equipped with sensors enabling its photo-luminescent fibers to transform and respond to visitors.

Biomimicry’s emphasis on problem solving distinguishes it from related concepts, such as biophilia (the hypothesis that humans have an innate need for connections with nature and other forms of life), biomorphism (design based on nature’s shapes and forms), bio-utilization (the direct use of nature—in green infrastructure, for instance), and bio-inspired design (a catch-all). The ideas these terms represent are distinct yet compatible, and a given scheme may combine more than one of them.

Biomimicry can generate solutions to a gamut of design challenges ranging from green chemistry to organizational development. But of particular interest for architects are biomimetic construction materials and the ways they are leading to more sustainable—and even regenerative—buildings. For example, looking to nature for ways to curb runaway carbon emissions reveals that biological processes kept pre-anthropogenic levels of atmospheric carbon dioxide confined within a narrow band for hundreds of thousands of years. That’s probably because, as CO2levels increased, blooms of coccoliths—marine microorganisms that form their skeletons from calcium carbonate, and become limestone when they die—transferred carbon from the atmosphere to the earth’s crust, regulating the balance. “Biology would solve the problem of climate change by making a lot more stuff out of atmospheric carbon,” says Michael Pawlyn, author of Biomimicry in Architecture and founding principal at London-based Exploration Architecture.

The BioRock Pavilion, Exploration Architecture’s concept for a small auditorium, does just that. BioRock, a technology originally developed by marine scientists and used in the restoration of coral reefs, grows limestone in seawater by running a low-voltage current through steel filaments; the current causes a chemical reaction that deposits carbon-sequestering limestone along the armature. And unlike, say, concrete manufacturing (which is responsible for 4 to 8 percent of the world’s CO2 emissions), this natural carbon-sequestering process is environmentally benign.

“There’s much to be gained from looking at the way materials are assembled in biology,” says Pawlyn, listing some of the key principles: low-energy production with locally available materials, the absence of persistent and bioaccumulative toxins, and interconnections within a closed-loop system in which everything can be—and is—reused.

A product generated according to these principles—in a process developed by Brent Constantz, founder of Blue Planet, a Los Gatos, California, company focused on economically sustainable carbon capture—is already being used commercially. Blue Planet grows carbon-sequestering aggregate for use in concrete or roadbeds by converting CO2 from the air or from flue gas—often from cement plants—into limestone. Instead of a current-charged wire armature, Blue Planet uses rock particles from solid industrial waste (such as concrete-demolition debris) to provide a nucleus around which limestone builds in water-based mineral solutions to sizes ranging from sand to gravel.

Because the aggregate’s carbon-sequestering coating is 44 percent CO2 by mass, the material completely mitigates the carbon emitted in the production and transport of the concrete it’s part of—and then some—to produce carbon-negative concrete: 3,000 pounds of aggregate in a cubic yard of concrete could sequester 1,320 pounds of carbon, more than offsetting the 300 to 600 pounds of embodied carbon the concrete would typically represent. It has been used in such projects as the San Francisco International Airport, and, if it were substituted for all 50 billion tons of aggregate quarried each year worldwide, it would sequester more than half the world’s annual anthropogenic carbon emissions, bringing atmospheric carbon down to preindustrial levels by 2050 singlehandedly, according to an estimate from the Foundation for Climate Restoration. With production facilities able to locate near ready-mix operations, the cost is generally less than that of quarried and transported aggregate, says Constantz, so the main challenge to widespread adoption is Blue Planet’s ability to open enough plants.

In addition to growing material by the strategic and adaptive accretion of available substances, biology tends to generate efficient but spectacularly complex, hierarchically organized systems to efficiently carry loads with minimal structure—an idea neatly summed up in an aphorism attributed to biologist and retired academic Julian Vincent: “In biology, material is expensive, and shape is cheap.”

PHOTOGRAPHY: KELLY HILL PHOTOGRAPHY

Exploration Architecture’s proposal for a crow-skull-inspired pavilion (left), depends on additive-manufacturing processes to place material precisely where it is needed. The firm’s concept for an auditorium (right) uses a technology originally developed to restore coral reefs.

One of the most elegant examples is birds’ skulls, for which evolution has prioritized lightness. Built up of fine layers of bone connected by tiny struts, they combine dome and space-frame technologies, says Pawlyn, whose crow’s-skull-inspired pavilion, now in design (with a still-confidential commission in the offing), demonstrates the principle. “Conventionally, it’s been very difficult to mimic the complexity of biology without a huge cost penalty,” he says. But now, with additive manufacturing processes placing material precisely and only where it’s needed, there’s no cost premium, says Pawlyn, “and there is actually the potential to save money by using less material.”

 

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Originally published in Architectural Record

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