Carbonated concrete curing uses carbon dioxide uptake during the hardening process to lock carbon into the concrete matrix, instead of relying only on water-based hydration. It offers a route to lower the net carbon footprint of concrete while potentially speeding up strength gain, which is why cement producers, materials-science spinouts and university groups have all filed in this space. Filing activity peaked in 2023 at 49 records in this dataset before pulling back sharply, so the technology has already moved past its earliest exploratory phase into more targeted claims on specific process steps and mix designs.

The assignee ranking behind this landscape covers 53 companies, and the leading filer holds 46 records — roughly double the fifth-ranked assignee's 23. Beyond the leader, the field includes a cluster of academic institutions and materials-science companies that co-file frequently, alongside a long tail of assignees with only a few filings each. That structure means one company sets much of the claim landscape, but there is still meaningful activity outside its portfolio worth tracking.

Filings dropped 72% between 2021 (29 records) and 2024 (8 records), which is a real and complete-year decline. However, patent publication typically lags actual filing by around 18 months, so the 2025 and 2026 figures in any dataset are still incomplete and should not be read as confirming a continued slowdown. The honest read is that filing activity cooled sharply through 2024; what happens after that is not yet visible in the published record.

Almost every record in this dataset — 99.5% of 185 records — falls under the C04B cement and refractories classification, which is expected given the scope. Within that, about a fifth of records (21.1%) also carry a B28B shaping-and-forming class, and smaller but notable clusters sit in B28C mixing, B01D separation processes, and E04G scaffolding and formwork. The overlap between curing-process claims and shaping or separation claims is where new filings are most likely to run into existing prior art.

US20240262743A1, assigned to HSustainability GmbH and filed in 2024, claims a specific method for separating hardened concrete paste from aggregate using electric-pulse fragmentation combined with a carbon dioxide-containing liquid feed. The claim ties particle-size bounds and a defined fine-fraction cut-off directly to the fragmentation and carbonation steps, which is the combination a design-around needs to clear. Anyone building a recycled-aggregate or demolition-waste carbonation process should check whether their particle-size control and CO2 dosing sequence falls inside that claimed combination before committing to a process design.