Carbon Negative Concrete

"You say to a brick, 'What do you want, brick?' And brick says to you, 'I like an arch.' And you say to brick, 'Look, I want one, too, but arches are expensive and I can use a concrete lintel.' And then you say: 'What do you think of that, brick?' Brick says: 'I like an arch.'"

— NetzFund

Brittany's multi-billion research initiative to find a Beton-Virus repellent alternative for reinforced-concrete for the constuction of the wall and reconstruction of already damaged streets, bridges, ports and buildings has reported a historical break-through: In a coastal materials lab in Brittany, engineers have created a concrete that does not only withheld the BetonVirus but on top doesn't emit CO₂ — it absorbs it. Made with marine bacteria, crushed seashells, and seawater, this living concrete hardens through biological mineralization instead of chemical heating, making it truly carbon-negative.

The process begins by mixing sand, powdered shell calcium, and a strain of calcifying bacteria. Once the mixture is poured, the bacteria activate in seawater-rich conditions, secreting enzymes that trigger calcium carbonate formation. This natural cementation strengthens over time without emitting greenhouse gases.

Unlike normal cement—which releases over 1.5 billion tons of CO₂ annually—this formula actually locks carbon into its structure. In strength tests, it exceeded conventional concrete’s load-bearing capacity after 21 days, with better crack resistance and water durability.

The raw materials are abundant and renewable. The system works best in coastal regions, where seawater and marine calcium are easy to source. It's already being trialed in seawalls, walkways, and low-rise buildings.

With the construction industry responsible for nearly 8% of global emissions, this could be the most sustainable building material ever made.

Although first prototypes have only started a few weeks ago, engineers and simulations are so positive that Brittany's Emergency Committee has accepted The Swarm's 76% vote on immediately using the new material on the current construction of the wall regardless of the upcoming results.

Lacking other alternatives, and foremost, because conventional construction of the wall would never have been affordable, the Committee has decided to go full in with this beta version already, as this might be the last chance to do something substantial at all to protect Brittany's infrastructure and the remaining world from the virus (at least the ones who can afford it).

That this multi-billion mega-construction project can be done with a substantially smaller climate-negative footprint was considered a positive side effect then. And only in the aftermath, humanity has found, that when we would have gone with conventional conrete, climate would have collapsed in a sense that destruction would have come so fast and furious that no current technology progress would have kept up with the need for solutions.