Hard Corals: CO2 Sequestering Concrete Aggregates — Blue Planet

Biological model: Hard corals (Scleractinia order)

Company: Blue Planet

Blue Planet developed concrete aggregates using CO2-sequestering minerals inspired by coral calcium carbonate structures. These aggregates lock CO2 into concrete, reducing emissions while improving building material sustainability.

The challenge

Concrete is one of the most carbon-intensive materials; we need low-carbon alternatives for massive construction needs

Nature's strategy

Hard coral (Scleractinia order) calcium carbonate skeleton formation

What was emulated

Mineral precipitation of calcium carbonate that sequesters atmospheric CO2

The innovation

Carbon-sequestering aggregates and concrete that lock CO2 into building materials

Full case study

Hard corals build their skeletons from calcium carbonate, extracting calcium and carbonate from seawater and precipitating it into mineral structures. The process sequesters CO2—the carbonate in shells and skeletons originally came from atmospheric CO2. Blue Planet developed an alternative cement technology based on this principle: instead of portland cement (which is extremely carbon-intensive to produce), they use CO2-sequestering aggregates. The process involves capturing CO2 (from industrial sources or directly from air), converting it to mineral form (calcium or magnesium carbonate), and using this as concrete aggregate or binder. The result is concrete that is carbon-negative: the carbon sequestered in the material exceeds the carbon emitted in production. Concrete production accounts for ~8% of global CO2 emissions; CO2-sequestering concrete could fundamentally transform construction's carbon footprint. Blue Planet's technology is commercially scaling; the aggregates work in standard concrete mix designs and perform comparably to conventional aggregates. The ultimate goal is net-negative concrete: materials that actually improve the atmosphere by sequestering more CO2 than their production emits. Additional benefits include utilizing waste CO2 from industrial sources (converting a waste product into a resource) and creating building materials that literally reverse climate change by the act of being produced.