Calcined Clay Cement Patents: Top Companies & Filing Trends 2026
An analysis of 782 calcined clay cement patent families from 2015 to 2026: filing trends, leading assignees, IPC technology composition and where white space remains for low-carbon cement formulators.
Filing growth = 2021 (95 records) → 2024 (84); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 782 records in scope (CR5), not the ranked leaders only.
What this landscape covers
Calcined clay cement, most often built around limestone calcined clay cement (LC3) chemistry, substitutes thermally activated clay and ground limestone for a share of clinker in cement and concrete formulations, cutting the CO2 intensity of the mix without a full process changeover. This landscape covers 782 published records filed between 2015 and the 2026 data cut-off, drawn from claims describing calcined clay cement compositions, cementitious binders and related processing methods classified predominantly under C04B.
The scope pulls in both construction cement and oilfield well-cementing formulations that use the same calcined clay chemistry, which is why some of the most-cited prior art in the dataset comes from drilling-fluid patents rather than building-materials patents. Receiving-office data shows the United States, Europe and the WIPO PCT route carrying the largest shares of filings, with Australia, India and Canada following behind.
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Filing trends and technology composition
The dataset spans 782 published records from 2015 through the 2026 cut-off, tracked across receiving offices and IPC subclasses to show where calcined clay cement activity concentrates and where it thins out.
Filing activity peaked in 2021 and has eased since
Annual filings rose from 17 in 2017 to a peak of 95 in 2021, then eased to 84 by 2024 — a -12% change over that three-year span. 2025 and 2026 figures are still filling in as publication lags filing by roughly 18 months, so the recent-year dip should not be read as a slowdown yet.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
C04B dominates; every other class is a minority branch
Almost every record in scope, 99.6% of the 782, carries a C04B cement or refractory classification, confirming this is a binder-chemistry field first. The next largest branches — materials for miscellaneous applications, furnace details, shaping processes, additive manufacturing, water treatment, well drilling and catalysis — each sit under 8% of records, marking them as secondary or adjacent claim territory rather than core ground.
Shares are the percentage of the 782 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
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Try EurekaRepresentative filing and most-cited prior art
Limestone calcined clay cement (LC3) construction composition
A limestone calcined clay cement construction composition comprising a cementitious binder with calcium silicate and calcium aluminate mineral phases at a defined Blaine surface area and dosage, combined with a supplementary cementitious material split between calcined clay and carbonate rock powder in a stated weight ratio and particle-size ceiling.Filed by Construction Research & Technology GmbH, published 2023-10-05 — illustrates the core LC3 composition-claim structure this field is built on.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4159302A | Fire door core | 251 |
| 2 | US5711383A | Cementitious well drilling fluids and methods | 226 |
| 3 | US5626665A | Cementitious systems and novel methods of making the same | 189 |
| 4 | US6133347A | Oligomeric dispersant | 169 |
| 5 | US5584926A | Cement compostion | 144 |
| 6 | US5788762A | Cementitious systems and methods of making the same | 129 |
| 7 | US6290770B1 | Cementitious mixture containing high pozzolan cement replacement and compatabilizing admixtures therefor | 124 |
| 8 | US6267814B1 | Cementitious dry cast mixture | 116 |
| 9 | EP2253600A1 | Portland limestone calcined clay cement | 108 |
| 10 | US6451881B1 | Oligomeric dispersant | 101 |
Citation counts are drawn from a searched corpus and favour older filings; read them as a signal of influence on later claim drafting, not of current commercial relevance.
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Four read-throughs from the dataset for teams deciding where to file, litigate, or license next.
A small leadership group, then a long tail
The leading assignee alone holds 85 families and the fifth-ranked holds 39, but the count drops to 16 by tenth place — the field is led by a handful of construction-chemicals, cement and oilfield-services companies with many smaller filers behind them.
A plateau after the 2021 peak, not a decline
Filing activity rose steadily from 17 in 2017 to a peak of 95 in 2021, then eased modestly to 84 by 2024. Because publication lags filing by roughly 18 months, treat the lower 2025-2026 counts as incomplete rather than a genuine drop-off.
Binder chemistry is the core; everything else is a minority branch
Cement and refractory classification C04B covers almost the entire dataset. The next largest branches — materials for miscellaneous applications, furnace details, shaping processes, additive manufacturing, water treatment, well drilling and catalysis — each sit under 8% of records.
The oldest compositions carry the deepest defensive moat
The most heavily cited records in this dataset are decades-old broad composition claims for cementitious systems and well-cementing fluids, not recent filings. Newer, narrower claims on dosage and particle-size ranges are comparatively easier to design around.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to low-carbon cement & concrete: calcined clay cement patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Sika Technology AG | EBERHARD BAU AG | 5 |
| Heidelberg Materials AG | HCONNECT 2 GMBH | 5 |
| Construction Research & Technology GmbH | SCOFIELD LM CO | 2 |
| Halliburton Energy Services, Inc. | RODDY CRAIG W | 2 |
| Halliburton Energy Services, Inc. | CURTIS PHILIP ANTHONY | 2 |
| Halliburton Energy Services, Inc. | COVINGTON RICKY L | 2 |
| Aalborg Portland A/S | HERFORT DUNCAN | 2 |
| Aalborg Portland A/S | DAMTOFT JESPER SAND | 2 |
Only 10 co-assignee pairs appear in the dataset, with the strongest pairs each linked by up to 5 shared records — evidence that most calcined clay cement patenting happens inside single organisations rather than through joint filing arrangements.
Where to take this next
The dataset points to a next set of questions that need claim-level detail rather than aggregate counts.
Check freedom to operate against the leaders
With the top five assignees holding 37.0% of the 782 records, a targeted freedom-to-operate read of their claim sets is the fastest way to see which formulation windows are already occupied.
Run a freedom-to-operate searchStress-test a white-space claim
Additive manufacturing, water treatment and catalysis branches each sit under 8% of records — thin enough to draft a first claim into before the space fills in.
Draft a claim in EurekaTrack the leadership group over time
A small set of construction-chemicals, cement and oilfield-services companies drive most of the filing volume; watching their newest publications flags shifts in strategy early.
Set up assignee monitoringFrequently asked questions
Calcined clay cement, often built around limestone calcined clay cement (LC3) chemistry, replaces a portion of ordinary Portland cement clinker with thermally activated clay and ground limestone, cutting the CO2-intensive clinker content of the mix. It is patented heavily because the performance depends on tightly specified variables — particle size distribution, surface area, calcination temperature, and the ratio of clay to carbonate — each of which can be claimed as its own composition window. That is why this dataset of 782 records sits almost entirely under the C04B cement and refractories classification rather than spreading evenly across construction categories.
Filing is concentrated at the top: the leading assignee in the ranked list holds 85 families, and the top five combined account for 37.0% of the 782 records in scope. That concentration drops off quickly — the tenth-ranked assignee holds only 16 families — leaving a long tail of smaller filers and single-patent entrants behind the leaders. Construction chemicals, cement producers and oilfield services companies all appear among the most active filers, reflecting calcined clay's use in both construction cement and well-cementing formulations.
Filings grew from 17 in 2017 to a peak of 95 in 2021, then eased to 84 by 2024, a -12% change over that three-year span — a plateau rather than a collapse. Because publication typically lags filing by around 18 months, the lower counts shown for 2025 and 2026 in the raw trend line are an artefact of incomplete data, not evidence of declining interest. Judged on the last complete year, 2024, filing activity remains close to its 2021 peak.
US20230312412A1, filed by Construction Research & Technology GmbH and published in October 2023, claims a construction composition combining a fine cementitious binder (at least 3800 cm2/g Blaine surface area, dosed 180-400 kg per cubic metre) with a supplementary cementitious material made of calcined clay and carbonate rock powder in a specified weight ratio and particle size ceiling. It blocks that specific combination of surface area, dosage and particle-size ranges, but it does not claim the general idea of mixing calcined clay with limestone — formulators working outside its stated numeric ranges have room to operate. Anyone developing an LC3-type mix should check their own binder fineness and dosage figures against this claim's stated bounds before assuming freedom to operate.
The branches furthest from the dense C04B core are the most open: additive manufacturing (3D-printable calcined clay mixes) sits at 2.8% of the 782 records, water and wastewater treatment uses at 2.4%, and catalysis-adjacent process claims at 2.0%. These are not empty, but they are thin enough that a well-specified combination claim — tying a particular calcined clay formulation to a printing rheology window or a contaminant-removal performance range — would have comparatively little prior art directly in front of it. The core binder-composition space, by contrast, is dense and best approached through narrow numeric differentiation rather than broad claims.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.