Low-Carbon Cement Patents: Who Leads, Where the Gaps Are 2026
- Filings peaked in 2022 at 98 and have not returned to that level, suggesting the current wave of calcined-clay and SCM claims is consolidating rather than still accelerating.
- A cluster of assignees shows 0 filings in the latest year with -100% YoY, including major cement producers — a sign that early claim positions are now being defended rather than expanded.
- C04B accounts for essentially the entire corpus (518 of 518 records), while related fields like CO2 capture (C01B), drilling cements (E21B) and metal extraction (C22B) remain thinly claimed by comparison.
What this landscape covers
This dataset tracks patent families filed against calcined clay, supplementary cementitious materials (SCM) and clinker substitution chemistry, spanning compressive strength development, hydration behaviour, durability and CO2 footprint claims within the C04B cement and refractories classification. The window runs from 2015 through the 2026-07-31 data cut-off, capturing both the early wave of calcined-clay activity and the more recent consolidation phase.
Because publication lags filing by roughly 18 months, the 2025 and 2026 counts in any trend line are understated relative to what will eventually be recorded — treat the most recent one to two years as a floor, not a ceiling.
Filing trend and technology composition
Two views of the same 518-family corpus: how filing activity has moved year over year, and which IPC subclasses carry the claims.
Filings rose then plateaued
Annual filings climbed from 14 in 2017 to a peak of 98 in 2022, then eased off. With 2022 sitting at the corpus midpoint and no year since exceeding it, the growth curve reads as flat-to-declining rather than still climbing — consistent with an already-crowded core rather than an emerging one.
C04B dominates; adjacent classes are thin
Every one of the 518 records sits in C04B (cement, ceramics and refractories), with much smaller counts spilling into C01B (inorganic compounds, 17), C09K (misc. materials, 16), B01D (separation processes, 15), E21B (well cements, 10), C01F (alkaline-earth compounds, 9), G01N (testing, 9) and C22B (metal extraction, 7). The concentration confirms this is a single-classification technology rather than one that has fragmented across adjacent domains.
Shares are the percentage of the 518 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Low-Carbon Cement and Clinker Substitution with Eureka
This page is one run against one query. Ask Eureka your own question about low-carbon cement and clinker substitution and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records and a representative claim
EP3524585A1 — Microwave-calcined clay as supplementary cementitious material
Use of clay calcined by microwave as supplementary cementitious material in composite binders, use of microwaves for calcining clay to be used as supplementary cementitious material, and a method for calcining clay comprising adjusting temperature and time so that substantial dehydroxylation is achieved without crystallization of the calcined clay.Filed by HeidelbergCement AG, published 2019-08-14.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20110067600A1 | Methods and compositions using calcium carbonate | 149 |
| 2 | US7922809B1 | Methods and compositions using calcium carbonate | 144 |
| 3 | US8114214B2 | Methods and compositions using calcium carbonate | 126 |
| 4 | US20070095255A1 | Blended cement composition | 99 |
| 5 | US8137455B1 | Methods and compositions using calcium carbonate | 92 |
| 6 | US8062418B2 | Methods and compositions using calcium carbonate | 92 |
| 7 | US20110067605A1 | Methods and compositions using calcium carbonate | 88 |
| 8 | EP3498681A1 | Use of carbonated recycled concrete fines as supplementary cementitious material | 80 |
| 9 | US20110203489A1 | Methods and compositions using calcium carbonate | 79 |
| 10 | US20110067603A1 | Methods and compositions using calcium carbonate | 77 |
Citation counts reflect influence within the searched corpus and skew toward older filings; they are not a proxy for current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about where this field stands
Reading the filing trend, IPC spread and citation pattern together points to a technology that consolidated around a small number of chemistries rather than one still branching outward.
Activity has plateaued since the 2022 peak
The corpus grew steadily from 14 filings in 2017 to a peak of 98 in 2022, then did not surpass that figure again. Combined with the 2022 midpoint sitting at the growth peak, this points to a field that front-loaded its claim activity rather than one still expanding.
Almost no cross-domain spillover
Every record in the corpus sits under C04B, with the next-largest subclass (C01B) carrying only 17 records. Adjacent fields like well cementing (E21B) and metal extraction (C22B) show only single-digit-to-low-double-digit activity, meaning claim strategy here is a single-classification game.
Leaders have gone quiet in the latest year
Multiple established assignees, including major cement producers, recorded zero filings in the most recent year with -100% year-on-year change. That pattern is consistent with a maturing core position being held rather than actively extended.
Filing strategy is genuinely multi-jurisdictional
The United States, Europe, India, WIPO/PCT, Canada and Australia all carry meaningful volume, with no single office dominating the way C04B dominates the IPC breakdown. That spread suggests assignees are pursuing parallel protection across major construction markets rather than concentrating in one home jurisdiction.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to low-carbon cement and clinker substitution, with the prior art for and against each one.
Who holds the ground, and where it is still open
Filing activity concentrates among a handful of cement producers and materials specialists, with co-assignee links pointing to a small number of active collaborations rather than a broad ecosystem.
One pairing dominates joint filing
Of the 10 identified co-assignee pairs in this corpus, the HeidelbergCement and HConnect 2 GmbH pairing is by far the strongest at 10 joint filings — an order of magnitude ahead of the next pairings, which sit at 2 each.
Several leaders show no latest-year activity
HeidelbergCement, Holcim Technology, Construction Research & Technology, Aalborg Portland, Envirotech and Roman Cement all show zero filings in the latest year, several with an explicit -100% YoY drop. This is a corpus where the incumbent set has been stable for years but is not currently adding new claims at pace.
A moderate-sized, single-domain corpus
At 518 patent families, this is a focused rather than sprawling technology area — small enough that a handful of strong assignees and one dominant co-filing pair can meaningfully shape the competitive picture.
| Assignee | Recent year | YoY |
|---|---|---|
| HeidelbergCement AG | 0 | -100% |
| Holcim Technology Ltd | 0 | -100% |
| Construction Research & Technology GmbH | 0 | — |
| Aalborg Portland A/S | 0 | — |
| Envirotech Corporation | 0 | -100% |
| Roman Cement, LLC | 0 | -100% |
| Calera Corporation | 0 | — |
| HCONNECT 2 GMBH | 0 | — |
Where to take this analysis
The landscape points to a consolidated core and a thinner set of adjacent branches — the next steps depend on whether you are clearing a filing or scouting white space.
Map claims against your own formulation
Run your specific calcined-clay, SCM ratio or hydration-modifier approach against the most-cited records to see how close your claim language sits to the dense prior art.
Explore this in Eureka →Track the quiet incumbents
Several major assignees show zero recent filings — worth monitoring for pending applications not yet published, given the 18-month publication lag.
Set up monitoring in Eureka →Scope the under-claimed branches
Well-cement clinker substitution and CO2 footprint quantification methods show comparatively light claim density relative to the C04B core — worth a deeper freedom-to-operate look before committing R&D.
Run a white space search in Eureka →Common questions about this landscape
In this corpus, SCM claims cover materials used to partially replace Portland clinker in cement blends, most commonly calcined clay but also other pozzolanic or latent hydraulic materials. Claims typically address either the material itself, a calcination or activation process for producing it, or a composite binder formulation incorporating it alongside clinker. The representative filing in this dataset, EP3524585A1, is a clean example: it claims microwave-calcined clay as an SCM, the calcination method, and the resulting binder material as three separate but related claim types.
The filing trend in this dataset rises from 14 in 2017 to a peak of 98 in 2022, then does not return to that level through 2026. This pattern is consistent with an early wave of foundational claims around calcined clay and SCM chemistry being filed and then defended rather than continuously expanded, though publication lag of roughly 18 months means the very latest years are understated and the apparent slowdown may partly be a reporting artefact rather than a real drop in R&D activity.
Filing activity in this corpus concentrates among established cement producers and materials science firms, with HeidelbergCement and its joint-filing partner HConnect 2 GmbH standing out as the strongest co-assignee pairing at 10 joint filings. Several of the most active historical assignees, including major cement producers, show zero filings in the latest recorded year, which suggests the field has a stable but currently quiet incumbent set rather than new entrants displacing them.
The clearest signal in this dataset is classification concentration: all 518 records sit under C04B, while adjacent classes like well-cementing (E21B, 10 records) and metal extraction byproducts (C22B, 7 records) carry very little dedicated claim activity. That gap suggests under-explored combinations, such as clinker-substitution chemistry adapted for oilfield well cements or SCMs derived from metal-extraction byproducts, are comparatively open relative to the dense core calcined-clay and blended-cement claims.
Citation counts in this corpus, such as the calcium carbonate composition patents cited well over 100 times each, reflect influence within the searched document set but skew toward older filings simply because they have had more time to accumulate citations. A recent filing addressing the same problem more efficiently may be under-cited purely due to age, so citation rank should be read as a signal of historical influence rather than a ranking of current technical importance.
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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.