Bone-Inspired Concrete for Carbon Capture

Concrete, the ubiquitous grey bedrock of modern civilization, underpins everything from our skyscrapers to our sidewalks.

It is, by far, the most consumed man-made material on Earth – a testament to its affordability, strength, and versatility.

Yet, this very ubiquity comes at a staggering environmental cost.

Accounting for roughly 8% of global greenhouse gas emissions, concrete’s silent contribution to the climate crisis is immense, a paradox that has long challenged engineers and environmentalists alike. Concrete: the most destructive material on Earth – The Guardian

For years, the industry has grappled with this burden, seeking solace in sustainable mixtures and more efficient designs, but the scale of demand often outpaces these earnest efforts.

Now, a team of researchers at the University of Pennsylvania, under the visionary leadership of Associate Professor Masoud Akbarzadeh, is offering a glimpse into a radically different future.

Their project, aptly named Diamanti, doesn’t merely tweak existing formulas; it reimagines concrete from its fundamental structure, drawing inspiration from one of nature’s most efficient designs: the human bone.

This isn’t just about using less material; it’s about making the material itself an active participant in carbon capture, turning a pollutant into a potential solution.

The core ingenuity of Diamanti lies in its dual-pronged approach.

First, it employs a novel, enhanced concrete mixture, developed in collaboration with Dr. Shu Yang’s Material Science Department.

This isn’t your grandfather’s concrete.

By partially replacing traditional cement with diatomaceous earth (DE), a naturally porous, silica-rich material derived from fossilized algae, the team has engineered a concrete that actively absorbs carbon dioxide. Using Diatomaceous Earth When Building a Home

Dr. Du Hongjian, a senior civil engineering lecturer at the National University of Singapore, not involved in the project but keenly observing, explains that DE creates microscopic “channels” within the concrete, allowing CO2 to penetrate below the surface.

The result? Diamanti’s mixture absorbs a remarkable 142% more carbon dioxide than conventional concrete mixes.What is the Carbon Footprint of Concrete? – Greenly

But the innovation doesn’t stop there.

The second, equally revolutionary aspect is the design itself. Recent advancements and future trends in 3D concrete printing indicate significant benefits.

Leveraging robotic 3D printing, Diamanti creates complex, lattice-like patterns inspired by triply periodic minimal surface (TPMS) structures found in porous bones. Triply periodic minimal surface – Wikipedia

“Through millions of years of evolution, nature has learned that you don’t need material everywhere,” Akbarzadeh explains, pointing to the efficient, load-bearing structure of a bone’s cross-section.

By mimicking these natural blueprints, the team has crafted a pedestrian bridge design that uses an astounding 60% less material while retaining – and even enhancing – its mechanical strength.

This material reduction isn’t just about saving resources; it directly translates to fewer emissions from production and transport.

Crucially, the bone-inspired design serves another vital function: it significantly increases the bridge’s surface area.

Concrete naturally absorbs some CO2 from the air, but as Hongjian notes, this reaction is typically limited to the exposed surface.

Diamanti’s intricate, porous structures expand this accessible surface area by another 30%, maximizing the interaction between the enhanced concrete and atmospheric carbon at a microscopic level. Solving Cement’s Massive Carbon Problem

“That contributes a lot to both (carbon dioxide) reduction and absorption,” Akbarzadeh affirms, highlighting the synergistic power of the material and design innovations.

The journey from concept to reality has been swift and promising.

Launched in 2022 with support from Swiss chemical company Sika and grants from the US Department of Energy, Diamanti has already seen its prototypes excel.

A five-meter test bridge proved feasibility, followed by a larger 10-meter version that passed rigorous load testing “with flying colors,” exceeding all expectations.

This impressive prototype is currently gracing the European Cultural Center in Venice, a testament to its architectural as well as engineering prowess.

While the dream of installing the first full-scale bridge in Venice was thwarted by changing city regulations, the project has now secured approval for its inaugural real-world structure in France, with a location still to be determined.

This move underscores the practical challenges of bringing groundbreaking research into the public sphere, yet it also signifies a critical step towards demonstrating Diamanti’s potential beyond the lab.

Akbarzadeh is eager to monitor the structure’s performance in a live environment, a crucial phase for any nascent technology.

Of course, no single innovation is a panacea.

Andrew Minson, director of concrete and sustainable construction at the Global Cement and Concrete Association, acknowledges the industry’s sustained efforts, noting a 25% reduction in carbon emissions per metric ton between 1990 and 2023. Top 10 Best Sustainable Building Practices

However, the International Energy Agency reports that overall sector emissions are higher today than in 2015 due to escalating global demand.

The energy-intensive process of producing cement – the binding agent in concrete – remains the largest culprit, largely due to the high temperatures required to break down limestone, which also releases CO2 as a byproduct.

The supply chain for diatomaceous earth, while promising, also presents a potential hurdle for widespread adoption, as Hongjian and Minson both point out.

Global production of DE was 2.6 million tons in 2023, a significant amount but still dwarfed by the colossal demand for concrete.

This reinforces Minson’s pragmatic view: “There’s no silver bullet. We need to be doing all the different actions that we can to manage material demands and reduce carbon.” Eco-Friendly Alternatives To Traditional Concrete

Yet, Diamanti offers more than just a niche solution.

It presents a paradigm shift in how we conceive of construction materials.

By demonstrating that concrete can be both structurally sound and environmentally restorative, the project opens “a whole new world of possibilities,” as Akbarzadeh envisions.

Beyond bridges, the team is already exploring applications in prefabricated floor systems, suggesting that the intricate, carbon-absorbing designs could become a fundamental component of future sustainable architecture.

In a world desperate for solutions to its environmental woes, Diamanti stands as a powerful example of how looking to nature, combined with cutting-edge technology, can transform even the most entrenched industries.

It’s a testament to the idea that our built environment doesn’t have to be a passive contributor to climate change, but can instead become an active partner in healing the planet, one bone-inspired, carbon-absorbing structure at a time.