The research, published in the journal Construction and Building Materials, examined whether red mud, a highly alkaline residue generated in enormous quantities by aluminum refining, could be combined with dredged sediment to replace a substantial portion of conventional Portland cement in concrete formulations. The team, led by Faber Chaparro and Mohamed Osman, both MSc and PhD graduates of 2026 respectively, along with their colleague Mohammad Almakhadmeh and supervised by Ahmed Soliman, associate professor in Concordia’s Department of Building, Civil and Environmental Engineering, estimated that the substitution could reduce greenhouse-gas emissions by anywhere from 25 to 50 per cent, depending on how the mixture is formulated. That range is significant because it suggests the approach is not a marginal improvement but a potentially transformative one for an industry under intense pressure to shrink its environmental impact.

The logic behind the study rests on a class of materials known as limestone calcined clay cements, often abbreviated as LC3, which have emerged in recent years as one of the most promising routes to lower-carbon concrete. Rather than relying almost entirely on clinker, LC3 blends combine clinker with calcined clay and limestone powder, allowing a large fraction of the traditional binder to be replaced while retaining most of the mechanical performance. The catch is that the clay must be of reasonable quality, rich in the reactive minerals that participate in the pozzolanic reactions responsible for strength development. Low-grade clays and dredged sediments, which are abundant and cheap, often fall short of that standard because they contain impurities and lack the reactive phases that make calcined clays useful binders.

This is where red mud enters the picture. Red mud is the caustic slurry left behind when bauxite ore is processed with sodium hydroxide to extract alumina, the feedstock for aluminum metal. It is produced at a rate of well over 150 million tonnes per year worldwide, and it accumulates in vast holding ponds that pose both environmental hazards and disposal costs for the aluminum industry. Chemically, however, red mud contains oxides of iron, aluminum, and silicon, along with residual alkaline compounds, several of which are precisely the kinds of constituents that can contribute to cementitious reactions if the material is properly activated. The Concordia researchers hypothesized that red mud could compensate for the deficiencies of low-quality dredged sediment, supplying the reactive components that the sediment lacks.

To test that hypothesis, the team first subjected both the red mud and the dredged sediment to a thermal treatment, heating them at 800 degrees Celsius. Calcination at this temperature drives off bound water and restructures the mineral phases, breaking down crystalline structures and creating amorphous, chemically hungry material that can dissolve and react in the alkaline environment of a hydrating cement paste. The researchers varied the duration of the heating and found that one hour produced the best overall results, maximizing the reactivity of the two materials without wasting energy on longer treatment. That finding matters for practical deployment, because the energy cost of the calcination step directly affects both the economics and the carbon accounting of the final cement.

With the activated materials in hand, the team prepared a series of blended cement formulations in which the treated red mud and dredged sediment replaced varying proportions of Portland cement. The mixtures were then evaluated for their physico-chemical performance, including the formation of hydration products and the mechanical strength of the resulting pastes and mortars. The results revealed a clear synergistic effect: red mud could offset some of the inherent limitations of the dredged sediment, promoting the formation of the compounds that give cement its strength. In several formulations, the combination of the two waste materials produced stronger products than mixtures containing the dredged sediment on its own, demonstrating that the pairing is more than the sum of its parts.

Equally important was the finding that dosage matters. The researchers observed that excessive amounts of red mud could reduce strength in some mixtures, a consequence likely tied to the material’s iron-rich composition and its residual alkalinity, which can interfere with normal hydration chemistry when present in high concentrations. At moderate levels, however, the red mud improved the structure and performance of the blended binder, refining the microstructure and supporting the development of strength-giving phases. This dose-response behaviour underscores a recurring theme in cement chemistry: supplementary cementitious materials are not interchangeable fillers but reactive components whose optimal proportions must be carefully calibrated for each combination of source materials.

The implications extend beyond the laboratory. Dredged sediment is generated continuously by ports, waterways, and harbours around the world, and disposing of it is a persistent logistical and environmental challenge, since contaminated sediments cannot simply be dumped back into ecosystems. Red mud, meanwhile, sits in accumulating stockpiles that occupy land and carry risks of alkaline leaching. If even a fraction of these two streams could be diverted into cement production, the construction industry would gain a low-cost, locally available source of binder materials while two waste-management problems would be partially solved at once. The emissions benefit compounds the appeal: because the waste materials displace both clinker and virgin raw materials, the approach attacks the carbon problem from two directions simultaneously, reducing the need for limestone calcination and for quarrying fresh clay.

The study, titled “Physico-chemical performance of red mud/dredged-based LC3,” was published on 12 September 2026 and received funding from the Natural Sciences and Engineering Research Council of Canada, the Fonds de Recherche du Québec – Nature et Technologies, and the Canadian Standards Association. The authors declared no known competing financial interests. As with any experimental cement research, the path from laboratory formulations to structural concrete will require further validation, including long-term durability testing, work on workability and setting behaviour, and assessment of how variability in waste-stream composition affects performance at industrial scale. But the core result stands: materials that industries currently pay to dispose of can be transformed, with a modest input of heat, into ingredients that make cement both stronger and substantially cleaner. In a sector where even single-digit percentage reductions in emissions are celebrated, a formulation capable of cutting greenhouse gases by up to half represents the kind of advance that could reshape how the world builds.

Subject of Research: Using red mud and dredged sediment as supplementary materials in low-carbon limestone calcined clay cement

Article Title: Research: Industrial waste can be a key ingredient in low-carbon cement, new Concordia study shows

Article References: Research: Industrial waste can be a key ingredient in low-carbon cement, new Concordia study shows. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: cement, red mud, dredged sediment, LC3, clinker, carbon emissions, Concordia University, construction materials, aluminum industry, waste valorization, calcination, sustainable building

The research, conducted by Farshad Malekpour, MASc 2026, and Mehdi Hojjati, a professor in Concordia’s Department of Mechanical, Industrial and Aerospace Engineering, was published in the journal Composites Part B: Engineering. The team set out to answer a question that sits at the heart of lunar in-situ resource utilization, or ISRU: can a space-grade polymer be recycled and blended with simulated moon soil to produce printed parts that actually perform under load? Their answer, demonstrated through a series of carefully controlled experiments, was yes, with important caveats about the trade-offs involved.

The material at the center of the study is poly(ether ketone ketone), commonly abbreviated PEKK, a high-performance thermoplastic prized in aerospace applications for its strength, thermal stability and resistance to harsh environments. Crucially, the PEKK used in the demonstrations was not virgin material. It had been recycled from a previously printed sacrificial structure, proving that this demanding engineering polymer can be processed and reused while retaining its thermal and mechanical properties. The researchers recycled the material three times and observed no significant degradation or loss of structural and mechanical performance, a result with major implications for missions where every gram of feedstock must be conserved and nothing can be wasted.

The recycling process itself was methodical. Collected PEKK scrap was shredded, milled into a powder, heat dried and then mixed with a commercially available lunar regolith simulant, a terrestrial stand-in designed to mimic the mineralogy and particle characteristics of actual moon soil. The resulting composite was extruded into filament and fed into a 3D printer, where it was formed into standard test shapes and into a sacrificial structure: a strong, lightweight, sponge-like configuration engineered to deform and absorb energy under load and then recover its original shape without damage. Sacrificial structures of this kind are not meant to be permanent load-bearing elements. Instead, they are designed to take the hit, so to speak, absorbing stresses the way the landing mechanism of a lunar module would have to cushion the shock of touchdown on the moon’s surface.

With the printed parts in hand, the researchers subjected them to a battery of mechanical and thermal tests. Samples were stretched, bent and compressed to measure how the composite responded to the kinds of stresses a real lunar component would encounter. Some specimens were also heat-treated to see how this additional processing step affected performance, an important consideration because any manufacturing process on the moon will have limited access to post-processing equipment. The team even printed a functional wrench from the same composite material, a small but symbolic demonstration that the blend can produce recognizable, practical tools rather than only test coupons.

The results revealed several genuine advantages of adding regolith to the polymer. The recycled composite showed strong thermal stability, and microscopic examination found the regolith particles evenly distributed throughout the plastic matrix, indicating a well-mixed, homogeneous material. Perhaps most significantly, the addition of regolith simulant lowered the temperature at which PEKK crystallized during heating, making the heat treatment process more efficient. On the moon, where energy is scarce and every watt counts, a material that crystallizes at a lower temperature translates directly into reduced power demands and faster processing cycles. The regolith also helped reduce shrinkage and warping during heat treatment, an advantage the researchers describe as especially important for manufacturing in an environment with little to no access to equipment for further processing. A warped part on Earth is a nuisance; a warped part on the moon may be an unusable one.

The composite was not without its weaknesses. The printed material exhibited more internal porosity than unmixed PEKK, and that porosity made the composite more brittle. Brittleness is a meaningful concern for components expected to absorb impact energy, since a material that cracks rather than deforms fails in a less forgiving way. The researchers note, however, that the recycled plastic itself was not degraded, meaning the brittleness stems from the regolith particles and the voids they introduce rather than from any breakdown of the polymer through repeated recycling. This distinction matters for mission design: it suggests engineers can plan around the composite’s limitations by reserving it for applications where energy absorption and dimensional stability matter more than maximum toughness, while keeping pure recycled polymer for parts that demand it.

What makes the study notable in the broader landscape of space manufacturing research is its circularity. Many proposed ISRU techniques envision using lunar soil as a bulk construction material, for example in sintered bricks or concrete-like structures, but few have demonstrated a closed loop in which a high-performance, space-grade polymer is recycled multiple times and combined with regolith in a single workflow. Hojjati says the study is among the first to demonstrate such a closed-loop approach, combining the recycling of PEKK with lunar regolith in this way. In a circular system, a sacrificial structure printed for one mission phase could be shredded, reprocessed and printed again for the next, with regolith extending the feedstock each cycle. The economics are compelling: every kilogram of locally sourced or recycled material is a kilogram that does not need to be launched from Earth at a cost that can reach seven figures.

The implications extend beyond the moon. Thermoplastic recycling of this kind could apply to any long-duration space mission where manufacturing scrap accumulates, from orbital fabrication facilities to Mars habitats, and the principle of reinforcing recycled polymers with locally gathered mineral fillers is adaptable to planetary surfaces beyond the lunar environment. The researchers are careful to frame the technology as still very new, and the study published on 25 July 2026 represents an early experimental demonstration rather than a flight-ready process. Real lunar regolith differs from simulants in ways that could affect printing behavior, and the porosity and brittleness observed in the composite will need to be addressed before such parts could be trusted in critical applications.

Even so, the work offers a promising pathway toward efficient use of scarce materials in space exploration, the researchers note. As space agencies and commercial partners move from brief sortie missions toward sustained lunar presence, the ability to print, use, recycle and reprint components from a blend of moon dust and recovered engineering polymer could transform the logistics of living off-world. The Concordia study provides a concrete, tested demonstration that the loop can close: a printed sacrificial structure becomes powder, the powder becomes filament, the filament becomes a wrench, and the moon itself supplies the filler. For a species hoping to stay on the lunar surface rather than merely visit, that kind of resourcefulness may prove to be the difference between an outpost that endures and one that never gets built.

Subject of Research: Recycled PEKK thermoplastic and lunar regolith composites for 3D-printed lunar infrastructure

Article Title: Simulated moon soil and recyclable thermoplastics could help build future space infrastructure, study shows

Article References: Simulated moon soil and recyclable thermoplastics could help build future space infrastructure, study shows. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: lunar regolith, 3D printing, PEKK, thermoplastics, in-situ resource utilization, recycling, space manufacturing, Concordia University, additive manufacturing, sacrificial structures, lunar habitat, composites

The study, published in the journal Journalism Practice, examined almost 2,000 news stories published between May and December 2023 by six Canadian and US news organizations: The Globe and Mail, Le Devoir, Le Journal de Montréal, The New York Times, The Boston Globe and The New York Post. The sample was deliberately broad, spanning English- and French-language coverage, prestige broadsheets and popular tabloids, and both straight news reporting and opinion writing. That breadth allowed the researchers to ask not only how often climate change came up, but which kinds of newsrooms, formats and contexts made those mentions more likely.

The headline finding is striking for anyone who has followed media scholarship on climate coverage. Nearly 40 per cent of all stories in the sample mentioned climate change, and more than 30 per cent explicitly connected the wildfires to it. Those figures stand far above the levels reported in earlier studies of disaster coverage, which the study’s corresponding author, Amélie Daoust-Boisvert, an associate professor in Concordia’s Department of Journalism, describes as typically ranging from only 2 to around 15 per cent. In other words, the 2023 fires produced some of the highest rates of climate attribution ever documented in mainstream press coverage of a natural disaster.

Daoust-Boisvert says the team was somewhat surprised by the sheer volume of climate mentions and connections they observed, given how low the levels found in previous studies tended to be. She was less surprised to find a gap between legacy broadsheets and tabloids, but noted that even the tabloids were not entirely silent on climate change. The co-author of the study is Brianna Losinger Ross, a PhD candidate in political science. Together, the two researchers combined automated text mining with human coding, a hybrid method that proved essential to the accuracy of their results.

That methodological choice matters. Keyword searches alone could flag climate-related terms in stories where no actual connection to the fires was being made. A phrase such as spreading like wildfire, for example, contains the word wildfire but says nothing about the climate. By manually reviewing the relevant stories, the researchers could distinguish genuine attribution from incidental vocabulary, avoiding the false positives that can inflate counts in purely computational analyses. This distinction between mentioning climate terms and making an explicit causal link is at the heart of the study’s contribution.

The analysis also revealed which factors most strongly shaped whether a story connected the fires to climate change. The likelihood of attribution varied most according to the newsroom producing the story and whether the piece was news or opinion. Language, country and whether a publication was a tabloid or a broadsheet had smaller effects. Opinion writing was by far the most climate-conscious category: almost 78 per cent of opinion pieces mentioned climate change, and about 65 per cent of them explicitly tied the fires to it. News stories lagged behind, with about 34 per cent mentioning climate change and 26 per cent making the explicit connection, a pattern consistent with the traditional reluctance of reporters to editorialize about causes.

One event appears to have acted as a turning point within the coverage period. In August 2023, the international scientific collaboration World Weather Attribution published a report examining the root causes of extreme climate events, concluding that climate change more than doubled the likelihood of the extreme fire weather conditions seen in Quebec. According to the researchers, climate mentions and connections became more pronounced after the report’s publication. Their statistical analysis shows clear trends before and after that date, suggesting that journalists seized on the peer-reviewed attribution work as the authoritative source they needed before asserting that climate change was involved in the catastrophe.

Daoust-Boisvert points out that journalists always need a source before they can write that climate change is involved in or contributing to a natural disaster, and that the World Weather Attribution report provided exactly that. She also notes that the field of extreme weather attribution has expanded considerably over the past few years, which means reporters increasingly feel confident making the link between warming and specific disasters going forward. The researchers suggest that media practices are shifting in part because of journalists’ better understanding of the scientific consensus around climate change and its relationship to extreme weather events. In effect, rapid attribution science is giving newsrooms a defensible factual basis for statements that once would have been treated as too speculative for straight reporting.

The findings arrive with important caveats. Daoust-Boisvert emphasizes that climate remains a politicized and polarizing topic, and that straightforward reporting on it faces pressure from influential voices across the political spectrum. Newsrooms navigating that landscape must weigh scientific evidence against audience expectations, ownership priorities and the risk of accusations of advocacy. The differences the study found between newsrooms and between news and opinion formats reflect those tensions, even in a year when the physical evidence of a climate-fuelled disaster was impossible to ignore.

There is also a subtler risk on the horizon. As extreme weather events become the new normal, Daoust-Boisvert cautions, they could lose their newsworthiness, leading to a decrease in the urgency of addressing anthropogenic climate change. The 2023 wildfire season, fuelled by record-breaking drought and unusually high temperatures, was voted the Canadian Press news story of the year, and its unprecedented scale helped push climate framing into the mainstream. Whether that realignment persists, or fades as such disasters become routine, may determine how effectively the media informs the public about the defining environmental challenge of the era. For now, the study offers quantitative evidence that a historic disaster can move journalistic norms, and that attribution science is becoming the bridge between the newsroom and the climate research community.

Subject of Research: Media attribution of the 2023 Canadian wildfires to climate change

Article Title: Canada’s 2023 wildfires broke longstanding media caution around climate reporting

Article References: Canada’s 2023 wildfires broke longstanding media caution around climate reporting. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: climate change, wildfires, journalism, media coverage, attribution science, World Weather Attribution, Concordia University, Canada, news analysis, extreme weather, Journalism Practice, climate communication