The research team, led by Désiré Ndahirwa of UniLaSalle with colleagues including Hélène Lenormand, Hafida Zmamou and Nathalie Leblanc, focused on a question that has dogged the field for years. Wood ash contains reactive silica, alumina and calcium-bearing phases that can, in principle, behave like cement itself, reacting with water through hydraulic and pozzolanic pathways. In practice, however, pastes made from pure wood ash are weak and porous. Previous studies had shown that replacing moderate amounts of cement with wood ash often reduces compressive and flexural strength, and most work had examined substitution levels below 50 percent. Almost nothing was known about what happens at very high replacement levels, where wood ash dominates the mixture, and the stiffness of such materials, measured as Young’s modulus, had rarely been quantified despite its importance for structural design.

To close that gap, the researchers gathered four locally sourced wood ashes from the Normandy region of France. Two of them, designated WFA3 and WBA, came from the combustion of wood pellets and were delivered as wet sludge, requiring oven drying and crushing before use. The other two, WFA8 and WFA9, arrived as dry fine powders from a local heating plant operated by Coriance in Mont-Saint-Aignan, where boilers with power inputs of 6 and 8 megawatts burn forestry wood chips, bocage wood chips and pallet residues at temperatures between 900 and 1100 degrees Celsius. The team prepared seventeen paste formulations in total: four containing only wood ash, twelve blending 80 to 95 percent wood ash with 5 to 20 percent ordinary Portland cement, and a reference paste of pure cement, all compacted with a mini-Proctor device to boost density and cured for up to 28 days.

The chemical analysis alone revealed why wood ash is such a tricky raw material. The four ashes were dominated by calcium oxide, silica, potassium oxide and sulfur trioxide, but in wildly varying proportions. Sulfate contents reached 15.4 percent in WFA8 and 14 percent in WFA9, far above the 4 to 5 percent limit set by ASTM standards for pozzolans, and their combined pozzolanic oxides fell well below the required thresholds. In plain terms, these ashes do not qualify as conventional pozzolans, yet X-ray diffraction showed they carry crystalline phases such as portlandite, calcite, albite, alite, dolomite and sylvite that can still participate in binding reactions. The variability is a direct consequence of differing feedstocks, boiler designs and combustion temperatures, and it means each ash must be evaluated on its own terms rather than lumped into a single category.

When it came to mechanical performance, the effect of the small cement additions was unmistakable. Pure wood ash pastes managed compressive strengths of only 0.13 to 1.65 megapascals at 28 days, but raising the cement content to 20 percent lifted those values substantially. The best performer was the WFA8-based blend, which reached 5.49 megapascals, while WFA9 and WFA3 pastes achieved 4.01 and 3.87 megapascals respectively at the same dosage. The researchers attribute the gains to a richer supply of hydration products, including calcium silicate hydrate gel, portlandite and ettringite, formed as the cement’s tricalcium silicate reacts with water and progressively densifies the paste matrix. Stiffness told the same story: the modulus of elasticity, estimated from the linear portion of stress-strain curves, climbed with cement content, curing time and bulk density in three of the four ash families, with the highest values consistently recorded in mixtures containing 20 percent cement.

One ash refused to follow the script. The wood bottom ash, WBA, behaved atypically across every measurement. Its pastes lost compressive strength between 7 and 28 days at certain dosages, its modulus of elasticity peaked at 7 days and then declined, and thermogravimetric analysis found no detectable portlandite whatsoever. X-ray diffraction offered an explanation: the WBA pastes contained no alite, the calcium silicate phase that drives strength development in hydrating cement, and their dominant crystalline phases were calcite and quartz. Adding 20 percent cement pushed the estimated calcite content up from about 47 to 63.5 percent while quartz fell, a signature of carbonation of calcium silicate hydrate or the formation of complex, less efficient hydrate phases, both of which are associated with increased porosity and weaker binding.

Scanning electron microscopy added a visual dimension to the story. Under the microscope, pure cement paste appeared dense and well packed, bristling with the products of hydration, while pastes made from 100 percent wood ash showed loosely arranged particles riddled with interparticle voids, along with unreacted ash grains and dark fragments of unburnt wood. With 20 percent cement added, the microstructure tightened, porosity dropped and hydration products proliferated, with needle-like ettringite crystals, gel-like calcium silicate hydrates, plate-shaped portlandite and rhombohedral calcite all visible. The ashes from the heating plant, WFA8 and WFA9, consistently produced more compact matrices than the pellet-derived WFA3 and the bottom ash WBA, underlining how much origin and processing shape a material’s destiny.

The mineralogical detective work also turned up some genuinely unexpected chemistry. In the WFA8 blends, introducing cement promoted the formation of alunite, a potassium aluminum sulfate hydroxide phase not present in the unblended paste, alongside an array of compounds including syngenite, arcanite, serandite and harmotome. Thermogravimetric analysis at 7 and 28 days complemented the diffraction data, identifying calcium silicate hydrates and ettringite dehydrating between 50 and 200 degrees Celsius, AFm phases such as calcium monocarboaluminate and hemicarboaluminate decomposing between 200 and 300 degrees, portlandite dehydroxylating between 400 and 500 degrees, and carbonates releasing carbon dioxide from 500 to 800 degrees. The two techniques agreed closely, with the single discrepancy being ettringite in the bottom ash pastes, which thermal analysis detected but diffraction did not, likely because its concentration fell below the instrument’s detection limit.

What emerges from the study is a nuanced but practical message. Low doses of ordinary Portland cement, between 5 and 20 percent, can meaningfully upgrade pastes in which wood ash makes up as much as 95 percent of the solid content, provided the ash is fine and reasonably reactive. The improvements in stiffness, strength and microstructure are real, even if the resulting materials remain suited to low-strength applications such as lightweight binders rather than load-bearing concrete. The decisive variable, the authors conclude, is the variability of the ash itself: its origin, chemistry and mineralogy govern everything from phase development to porosity. That insight carries weight well beyond Normandy. With millions of tons of biomass ash generated annually and cement production responsible for a major share of global carbon dioxide emissions, even modest cement dosages that transform a landfill-bound waste into a functional building material represent a meaningful step toward circular, lower-carbon construction. The next challenge will be standardizing how ashes are characterized and selected, so that builders can trust what is in the bag before it ever reaches the site.

Subject of Research: The effect of low ordinary Portland cement content on the stiffness, microstructure and mineralogical composition of wood ash-based pastes

Article Title: Effect of low ordinary Portland cement content on stiffness, microstructure and mineralogical composition of wood ash pastes

Article References: Ndahirwa, D., Lenormand, H., Zmamou, H., Chenot, E., Potel, S., & Leblanc, N. (2026). Effect of low ordinary Portland cement content on stiffness, microstructure and mineralogical composition of wood ash pastes. Cleaner Engineering and Technology, 34, Article 101303. https://doi.org/10.1016/j.clet.2026.101303

Image Credits: AI Generated

DOI: 10.1016/j.clet.2026.101303

Keywords: wood ash, ordinary Portland cement, Young's modulus, compressive strength, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, calcium silicate hydrate, ettringite, porosity, biomass ash, sustainable construction

The scale of the problem is difficult to overstate. The construction industry contributes an estimated 33 percent of global carbon emissions, driven by energy-intensive cement production, the depletion of non-renewable aggregates, and the sheer volume of debris generated by rapid urbanization. In regions experiencing construction booms, and in areas devastated by earthquakes or severe weather, mountains of broken concrete accumulate faster than they can be absorbed. Traditional disposal through landfilling is becoming untenable, as land grows scarce and disposal costs climb. Recycling, the authors argue, is the most viable circular-economy strategy available once a concrete structure reaches the end of its service life and direct reuse or refurbishment is no longer feasible.

The technical logic of concrete waste recycling is straightforward in principle. Demolished concrete is collected, sorted and processed through crushing, screening and contaminant removal, with steel reinforcement, impurities and off-specification particle sizes separated out. The output is a family of secondary materials: recycled coarse aggregates, recycled fine aggregates and recycled concrete powder. These can partially replace natural aggregates in new concrete mixes, and the fine powder can substitute for a portion of cement in suitable proportions. The environmental payoff is twofold: waste is diverted from landfill, and the demand for virgin aggregates and cement, both of which carry heavy carbon footprints, is reduced. Empirical studies cited in the review also point to economic benefits, including revenue generation, job creation and technological development.

Yet the reality on the ground is far less circular than the theory suggests. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, methodology, the team searched the Scopus and Web of Science databases for English-language peer-reviewed publications from 2000 onwards. An initial haul of 1,642 records was progressively filtered down through language and year screening, duplicate removal and full-text assessment, ultimately yielding 65 scholarly publications for detailed analysis. These studies, published between 2004 and 2025, spanned 25 countries, with China contributing the most research (14 studies), followed by Australia (8), Malaysia (5), and the United Kingdom and Hong Kong (4 each). The geographic distribution reveals a striking imbalance: research on concrete recycling is heavily concentrated in parts of Asia, Europe and Oceania, while African and many developing-country contexts remain largely underrepresented in the literature.

From these 65 studies, the researchers identified 30 distinct barriers to concrete waste recycling, grouped into six categories: regulatory and policy, financial and economic, technical and technological, social and behavioural, market, and organizational and operational. Five barriers dominated the literature. High initial investment costs for recycling equipment and infrastructure were the most frequently reported, appearing in 14 studies. Close behind were poor quality and limited applications of recycled concrete products (12 studies), lack of comprehensive governmental regulations and guidelines (10), limited availability of advanced recycling technologies (10) and insufficient recycling facilities (10).

The quality problem deserves particular attention because it is fundamentally rooted in materials science. Recycled aggregates typically carry a layer of adhered cement mortar on their surfaces, which increases water absorption and porosity. This porous structure degrades the mechanical strength and durability of new concrete made with these aggregates, which is why recycled products are frequently restricted to lower-grade applications such as road base, pavements and drainage systems rather than structural concrete. Various treatment techniques have been developed to strip away the adhered mortar, including mechanical, thermal, chemical, microbial and supplementary cementitious material-based approaches. Among these, carbonation-based conditioning, in which recycled aggregates are exposed to carbon dioxide, has attracted growing interest because it can simultaneously improve aggregate performance and lock away carbon, contributing to emissions reduction.

Social and behavioural factors compound the technical ones. The review found that stakeholder resistance, ingrained preference for traditional practices, skepticism about recycled material quality and limited awareness of recycling benefits all slow adoption. Theoretical framing in the study draws on Diffusion of Innovation theory, which explains how new practices spread through social systems at different rates depending on perceived benefits, compatibility and complexity, and on Attitude theory, which holds that individual and collective attitudes shape behaviour. If industry leaders champion concrete recycling, the authors note, others are more likely to follow; conversely, misconceptions about recycled product quality can harden into industry-wide reluctance.

The study’s answer to these barriers is a set of 19 critical success factors organized into four domains. Legal and regulatory drivers include clear technical standards, quality certification systems, recycling targets, landfill restrictions, minimum recycled-content requirements, public procurement criteria and landfill taxes, all backed by enforcement, audits and accountability mechanisms. Economic and market drivers encompass grants, subsidies, tax reductions, competitive pricing of recycled aggregates and the strategic location of recycling centers near demolition sites to optimize transport logistics. Infrastructure and technology drivers involve government-supported land allocation for regional recycling hubs, investment in advanced processing technologies, and digital tools such as Building Information Modelling, RFID-enabled material tracking, material passports and AI-supported logistics platforms. Knowledge and education drivers include targeted professional training, public awareness campaigns, collaborative knowledge-sharing platforms, and pilot and demonstration projects that validate recycled concrete performance.

The most novel contribution of the review is its integrated conceptual framework, which links these success factors to the specific barriers they mitigate and assigns roles to the stakeholders across the concrete recycling value chain. Governments and regulatory authorities set policy direction and enforce standards. Construction and demolition enterprises practice selective demolition and waste segregation. Clients and project owners stimulate demand by writing recycled-content requirements into project briefs and tenders. Consultants and built-environment professionals influence material selection through design specifications. Recycling enterprises process the waste, concrete producers incorporate the resulting aggregates into new mixes, and educational institutions generate the evidence base and train the workforce. The public and non-governmental organizations round out the picture through awareness-building and implementation monitoring.

The authors are candid about the limitations of their work. The review drew only on Scopus and Web of Science, restricted to English-language publications from 2000 onwards, which may have narrowed the temporal, geographic and linguistic diversity of the evidence. The frequency analysis indicates how often barriers and success factors appear in the literature, not their relative severity or causal influence. Future research, they suggest, should empirically validate the framework across different regulatory and economic contexts, pursue longitudinal studies of policy instruments and market-development strategies, and pay far more attention to developing countries, where weak infrastructure and enforcement may shape recycling outcomes very differently.

Still, the message of the review is unambiguous. Concrete waste recycling is not merely a technical challenge to be solved with better crushers. It is a systemic problem requiring coordinated interventions across policy, finance, technology, markets and human behaviour. With the right mix of regulation, incentives, advanced processing and stakeholder collaboration, the rubble of yesterday’s cities could become the raw material of tomorrow’s, closing one of the largest and most stubborn material loops in the global economy.

Graphene’s promise for cementitious composites is well known, but conventional routes to high-quality graphene often struggle with scalability and cost. Here, the authors focus on shear exfoliation, a mechanical approach that can separate graphene layers from bulk materials using controlled shear forces. Unlike energy-hungry or batch-limited methods, shear exfoliation is designed for continuous processing, offering a practical pathway from laboratory demonstrations to factory floors.

The technical heart of the study is the way the graphene is produced and integrated. The team refines a shear-exfoliated graphene workflow to generate dispersible graphene suitable for mixing into cement systems. Dispersion matters: poorly dispersed graphene tends to agglomerate, reducing effective surface area and limiting the pathways through which graphene can influence hydration and microstructure.

Once incorporated into concrete made with recycled aggregates, the graphene acts on multiple scales. At the nanoscale, graphene’s large specific surface can interact with cement hydration products, supporting more refined formation of binding phases. At the microscale, the improved packing and altered pore structure contribute to stronger connectivity across the hardened matrix, which translates to better mechanical performance.

A key claim of the study is that performance improvements come while keeping the carbon implications favorable. By enabling high-performance concrete using recycled inputs, graphene-assisted formulations can reduce reliance on virgin materials. In turn, that reduction supports a lower overall embodied footprint, aligning material innovation with climate goals.

The researchers also emphasize reproducibility and controllability—properties required for a “viral science news” moment that extends beyond proof-of-concept. If shear exfoliation can be scaled while preserving graphene quality, construction materials could gain a new class of additives produced through mechanically driven, potentially lower-cost manufacturing.

For an industry audience, the message is straightforward: graphene doesn’t need to remain a niche lab material. With scalable shear exfoliation, graphene can move toward engineered cement composites where durability, strength, and sustainability are optimized together.

Overall, the study positions graphene not as an exotic additive, but as an industrially manufacturable ingredient tailored for recycled concrete. If the approach holds under real-world mixing, curing, and long-term testing, it could reshape how engineers think about both materials performance and carbon reduction in the built environment.
< strong>Subject of Research: Scalable production and application of shear-exfoliated graphene in recycled concrete for high performance and lower carbon footprint.
Article Title: Scalable shear-exfoliated graphene for high-performance low-carbon recycled concrete.

Article References: Abden, M.J., Tam, V.W.Y., Afroze, J.D. et al. Scalable shear-exfoliated graphene for high-performance low-carbon recycled concrete. Commun Eng (2026). https://doi.org/10.1038/s44172-026-00732-2

Image Credits: AI Generated

DOI: 10.1038/s44172-026-00732-2

Keywords: graphene; shear exfoliation; recycled concrete; low-carbon materials; cement hydration; composite performance.

At the heart of this groundbreaking innovation is the decoupling of the building material’s lifecycle from the building’s use phase. Unlike traditional masonry, which relies on permanent mortar joints, these industrially prefabricated brick wall elements are united through reversible joint solutions that facilitate non-destructive disassembly. This method ushers in a new paradigm for circular construction, where bricks maintain their value and functionality across multiple building lifecycles. Initial experimental results reveal a promising scenario: over three separate life cycles, CO₂ emissions can be reduced by a staggering 60 percent compared to conventional brick construction methodologies. Such an emission reduction is not merely incremental but transformative, signaling that reusability of high-quality building materials is a viable strategy in sustainable architecture.

The environmental rationale for reusing bricks is compelling. Brick production demands significant energy and resource input, making it one of the more resource-intensive building materials. By salvaging bricks intact post-demolition, the energy embedded within them is preserved, and the demand for new brick manufacturing diminishes drastically. This aspect is crucial as the construction sector currently accounts for one of the highest proportions of global carbon emissions. The life cycle assessment data affirm that significant emissions spikes occur during the initial phase of material production. Hence, extending brick utility via reusable wall systems circumvents repeated emissions tied to conventional mortar joint demolition and brick replacement.

Developing a reusable brick wall that maintains stringent structural standards posed formidable challenges. The system must adhere to tolerances maintaining dimensional accuracy, ensure load-bearing stability, provide airtightness, and guarantee sufficient thermal insulation—all without the rigidity of conventional mortar. Engineers solved these hurdles by optimizing wall thickness at 44 centimeters and integrating insulating wool within the bricks to meet modern thermal performance codes. Additionally, walls are prefabricated and pre-plastered within controlled factory environments to minimize onsite labor and installation errors. Two principal stabilizing techniques were innovated: either using a sufficiently heavy roof structure to provide downward compressive force or employing vertically aligned, pre-stressed threaded rods penetrating through the bricks. This dual approach ensures robustness under varying architectural configurations.

An essential breakthrough was the design of the reversible joint—a structural interface that combines the mechanical interlock and sealing requirements essential for building envelopes. Unlike traditional mortar, which irreversibly bonds brick units, these joints permit disassembly while maintaining load transfer capabilities. Micro-vibration analysis techniques, commonly referred to as modal analysis, were leveraged throughout the research to non-destructively monitor the structural health of these wall elements. By stimulating the prefabricated walls with vibrational energy, researchers established baseline natural frequencies corresponding to the healthy, undamaged state. Future frequency shifts indicate variations in structural integrity or load-bearing capacity, allowing predictive maintenance without intrusive inspection or invasive testing.

To validate their theoretical and laboratory work, the team constructed a full-scale demonstrator building composed entirely of these prefabricated brick walls. This prototype underwent assembly, dismantling, transportation, and reassembly at a new location, demonstrating extraordinary resilience and functional equivalence throughout the process. Remarkably, the building retained all architectural and structural characteristics after repeated use, confirming the robustness of the reversible joint and the overall construction system under practical conditions. This success not only substantiates the technical soundness but also points toward promising market applications where building reuse is economically advantageous and environmentally imperative.

The pioneering project further highlights a critical yet unaddressed issue in conventional construction—residual building value. Standard practice results in buildings becoming liabilities at the end of their service lives, generating costly demolition waste and demanding fresh resources. With reusable brick wall systems, buildings gain residual value as disassembled elements can be reconfigured or repurposed without loss of integrity. This value retention empowers property owners by enhancing asset longevity and offers an environmentally conscious approach, aligning with global sustainability targets.

Behind this innovation lies interdisciplinary collaboration among TU Graz’s Institutes of Building Physics, Services and Construction, Structural Design, and Structural Engineering, combined with Wienerberger’s manufacturing expertise. This synergy has enabled a holistic approach encompassing material science, structural mechanics, thermal dynamics, and practical assembly techniques. The Austrian Research Promotion Agency FFG supported the project financially, underscoring the growing institutional commitment to sustainable construction technologies.

The project’s implications extend well beyond bricks and buildings. It exemplifies how industrialized prefabrication married to smart engineering can create circular material flows in sectors historically dominated by linear, wasteful practices. As urbanization continues globally, and building stock expands rapidly, the relevance of reusable structural components cannot be overstated. The technical successes established here pave the way for further innovation; for example, integrating smart sensors for real-time structural health monitoring, optimizing joint designs for faster assembly, or even scaling to other building components beyond walls.

From a policy perspective, introducing circular construction techniques necessitates new building codes and standards recognizing reversible joints and reused materials. Market acceptance will hinge on demonstrating lifecycle cost savings alongside ecological benefits. Educational initiatives aimed at architects, engineers, and construction workers will be vital in proliferating these methods. Importantly, the research sets a precedent for incentivizing deconstruction over demolition, shifting industry mindsets toward preservation and reuse.

Looking ahead, the durability of these prefabricated brick wall elements over prolonged timeframes remains a focus. The application of modal analysis as a monitoring tool is foundational here, allowing stakeholders to ascertain when components require intervention, refurbishment, or final recycling. This predictive capacity enhances safety while optimizing material usage, shaping a proactive approach to building maintenance.

In conclusion, the TU Graz and Wienerberger collaboration has delivered not merely a new construction product but a transformative concept aligning architecture with circular economy principles. Reusable prefabricated brick walls embody a pragmatic convergence of engineering innovation and environmental responsibility capable of reshaping the construction landscape. As this technology matures and expands its reach, the potential for significantly lowering the sector’s carbon footprint and resource demand is immense. The future might well see a construction industry where bricks themselves narrate stories of buildings past, revived anew without waste and with minimal ecological cost.

Subject of Research: Not applicable

Article Title: A Reusable Prefabricated Brick Wall System for Circular Construction: Development, Structural Concept, and Life Cycle Potential

News Publication Date: 12-Aug-2026

Image Credits: IBPSC – TU Graz

Keywords

Circular construction, reusable brick walls, prefabrication, reversible joints, building lifecycle, CO2 reduction, sustainable architecture, construction waste, structural health monitoring, modal analysis, building physics, industrialized construction

AMHERST, Mass. — Researchers at the University of Massachusetts Amherst recently unveiled a tool to combat climate change, fossil-fuel dependency, skyrocketing home-heating bills and gentrification all at once—a simple fabric treated with a special photothermal dye that, when placed on outside walls, can help keep a home 8.64ºF warmer over the course of a day.

“Sometimes, a simple solution works best,” says Trisha Andrew, professor of chemistry at UMass Amherst, and one of the paper’s senior authors, along with Carolina Aragón, associate professor of landscape architecture, and Ho-Sung Kim, senior lecturer in building and construction technology.

“When you’re cold, you put on a sweater,” says Aragón, “so we started thinking: what would you do if you’re a building?”

Heating buildings is a huge driver of fossil-fuel consumption, greenhouse gas emissions and energy insecurity. Over 33 million homeowners in the U.S. report trouble keeping their houses warm, and more than 24 million people—often renters—report skipping food or rationing energy in order to pay for heat. Meanwhile, according to the U.S. Energy Information Administration, residential and commercial buildings account for 39.1% of the primary energy used in the U.S. Reducing heating costs also translates into an enormous reduction in CO₂ emissions.

The typical way to address an inefficient home is to tighten it up: new windows and doors, more and better insulation, etc. But if you’re a renter, these options aren’t necessarily open to you. Worse is the phenomenon of “reno-viction,” where a landlord upgrades their property and then raises rents beyond what’s affordable for their current tenants. “Too many people have to choose whether they heat or eat,” says Aragón.

But what if keeping a house snug were as easy and affordable as putting on a sweater?

Andrew, among whose specialties includes inventing high-tech fabrics that can mimic animals adapted to extreme cold—like polar bears—and Aragón, who has long worked at the community scale to tell the story of climate change, teamed with Kim, who is an expert in modeling architectural designs for their energy usage.

The team initially thought of a building blanket, but ultimately what they designed and tested looks much more like jewelry: a series of removable tiles or panels that can be hung on any surface which not only conduct the sun’s warmth but insulate the building.

The key is a special photothermal dye that Andrew invented. “We can put this dye on anything,” Andrew says. “It doesn’t have to be on an expensive fabric. We chose to test it on umbrella fabric—something that was rugged and robust but still affordable.”

When they modelled their design, the results were eye-popping.

“We saw up to a 15% decrease in energy costs for a residential building in a northern climate, like Massachusetts,” says Andrew, “and up to 23% reduction in a large, 16-story apartment building.”

By comparison, a well-done traditional home renovation might yield a 2% reduction in energy costs.

These panels could even be sold as do-it-yourself projects that any renter could complete. The team imagines a scenario where people head to their local hardware store, buy a roll of the fabric and a few 2x4s and, in an afternoon, have a cheap and effective way of helping to heat their homes.

“Because the heart of this technology is a dye, we can use it to make panels that are beautiful and blend in with the specific culture and aesthetics of an area,” says Aragón. “It’s important to get the architectural and aesthetic part of this right, in addition to the science.”

But before consumers rush out to ask for the miracle fabric, the team needs to conduct additional, real-world testing. Though they’ve proven the concept in the lab, they need more data and field tests with life-sized prototypes.

“This could have an enormously beneficial societal impact,” says Andrew, and Aragón agrees: “there’s a role for anything that is empowering at the individual scale.”

The research appears in the journal ACS Applied Engineering Materials.

Contacts: Trisha Andrew, tandrew@umass.edu

                 Carolina Aragón, caragon@larp.umass.edu

                 Daegan Miller, drmiller@umass.edu

About the University of Massachusetts Amherst 

The flagship of the commonwealth, the University of Massachusetts Amherst is a nationally ranked public land-grant research university that seeks to expand educational access, fuel innovation and creativity and share and use its knowledge for the common good. Founded in 1863, UMass Amherst sits on nearly 1,450-acres in scenic Western Massachusetts and boasts state-of-the-art facilities for teaching, research, scholarship and creative activity. The institution advances a diverse, equitable, and inclusive community where everyone feels connected and valued—and thrives, and offers a full range of undergraduate, graduate and professional degrees across 10 schools and colleges and 100 undergraduate majors.  

The benefits of using rice husk ash cannot be overstated. It is rich in silica, a crucial component that contributes to the pozzolanic activity required for effective cement hydration. The fine particles of RHA provide a high surface area that can react with calcium hydroxide, a byproduct of cement hydration, to form additional cementitious compounds. This reaction results in improved strength, durability, and resistance to aggressive environmental conditions. Traditional cement production, in contrast, is a significant source of carbon emissions; thus, blending materials like RHA can foster more sustainable construction practices.

Nanomaterials have also gained attention for their potential to revolutionize the field of construction. When blended with ordinary Portland cement, these materials can significantly modify the microstructure of geopolymer cement composites. The fascination with nanomaterials stem from their unique physical and chemical properties, which can enhance the mechanical strength and enhance the resilience of the final product. Researchers are currently exploring various nanomaterials such as nano-silica, carbon nanotubes, and titanium dioxide to determine their synergistic effects when combined with RHA in cement matrices.

The amalgamation of RHA and nanomaterials sets the stage for innovation in composite materials, enabling engineers to tailor blends that not only perform exceptionally well under compressive loads but can also withstand harsh environmental conditions. Such advancements might prove vital for regions prone to aggressive weather patterns or for structures requiring longevity in marine environments. The transportation and construction sectors, which account for vast energy consumption and resource usage, stand to benefit immensely if these materials can be effectively employed in real-world applications.

Moreover, the sustainability implications of utilizing RHA and nanomaterial blends extend beyond structural integrity. Reduced dependence on conventional cement leads to decreased energy usage and carbon emissions, aligning with global goals for sustainable development. The production process of conventional cement is not only carbon-intensive but also demands vast quantities of raw materials and water. By adopting RHA-based composites in construction, the industry can pivot towards eco-friendlier methodologies that preserve natural resources while still meeting the infrastructural needs of an ever-growing global population.

However, the journey towards widespread adoption of RHA and nanomaterial composites is fraught with challenges. One major concern is the variability in the properties of RHA, which can be influenced by factors such as the type of rice, burning temperatures, and methods of processing. Such variations can affect the performance of cement composites significantly. Researchers are actively investigating ways to standardize the characteristics of RHA, ensuring consistency and reliability in its application for construction.

To improve the understanding of the interactions between RHA, nanomaterials, and conventional cement, detailed studies into their microstructural properties are necessary. It is essential to explore how the morphology and size distribution of RHA and nanomaterials influence the overall performance of the cement composites. Advanced imaging techniques and analytical methods play a crucial role here, revealing the nuances of particle interactions and the development of creating durable bonding phases.

The collaboration between academia and industry is crucial for accelerating the transition from laboratory-scale innovations to commercial applications. As researchers unveil the potential of RHA-blended cement composites, industry stakeholders must engage by conducting field trials that validate the findings through real-world performance assessments. This connection between research and application not only strengthens the empirical base but also fuels investment in novel material solutions.

Furthermore, public awareness of environmental issues linked to construction practices fosters an environment conducive to the acceptance of RHA and nanomaterial composites. As builders and consumers increasingly prefer sustainable options, there is mounting pressure on manufacturers to innovate. Demonstrating the benefits of RHA and nanomaterial composites effectively to policymakers, contractors, and the public could stimulate wider implementation and a shift in building material standards.

In the broader context, the integration of materials like RHA represents a significant opportunity to build resilient infrastructure that can withstand future challenges. Climate change, urbanization, and resource scarcity are pressing issues that demand innovative solutions in construction. RHA and nanomaterials, accordingly, represent not only a scientific advancement but also a response to these existential concerns about resource and environmental sustainability.

In conclusion, the future of cement composites leans toward utilizing waste and innovative materials like rice husk ash and nanomaterials. The ongoing research demonstrates a promising path towards developing materials that optimize performance while aligning with sustainability goals. Addressing the challenges inherent in using these materials will be crucial as the construction industry moves towards greener alternatives. With continued research and collaboration between scientists and industry professionals, the transformation of the built environment into a sustainable, eco-friendly space may indeed become a reality.

Through years of persistence in research and development, it is becoming evident that building materials have the potential to undergo a monumental transformation. The exploration and utilization of low-impact alternatives, like RHA and nanomaterial blends, can pave the way for sustainable construction practices, addressing both immediate and long-term challenges in a world that increasingly depends on resilience and innovation in its building processes.

Subject of Research: Rice husk ash and nanomaterial-blended cement composites

Article Title: Rice husk ash and nanomaterial-blended cement composites: a review

Article References:
Samarajeewa, P., Buddika, S., Yapa, H. et al. Rice husk ash and nanomaterial-blended cement composites: a review.
Environ Sci Pollut Res (2026). https://doi.org/10.1007/s11356-025-37361-9

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s11356-025-37361-9

Keywords: Rice husk ash, nanomaterials, cement composites, sustainability, pozzolanic activity, construction, eco-friendly materials, durability, waste management.

Fly ash, a byproduct of coal combustion in power plants, has been recognized for its pozzolanic properties, which allow it to react with calcium hydroxide in the presence of water to form compounds with cementitious properties. This transformation is fundamental for creating a durable binding material essential for construction. While fly ash on its own offers various advantages, it often presents certain limitations related to setting times, workability, and strength development. Consequently, researchers have been actively seeking ways to modify fly ash geopolymers to improve these attributes.

In their groundbreaking study, the researchers investigated the effect of incorporating calcium formate into fly ash-based geopolymer cement. Calcium formate, a soluble calcium salt, is known for its ability to accelerate the hydration process in cement. By introducing this additive, the team aimed to enhance the early-age properties of the geopolymer, thereby addressing the common drawbacks associated with fly ash cements. Their experimental results indicated a notable enhancement in workability, compressive strength, and setting times when calcium formate was added.

The study detailed how varying the concentration of calcium formate significantly influenced the performance of the geopolymer cements. At optimal concentrations, the calcium formate not only accelerated the hydration reaction but also contributed to the formation of calcium silicate hydrates, which are critical for the strength and durability of the hardened product. This finding is significant for the construction industry, where rapid setting times and enhanced mechanical properties are often essential requirements for various applications.

Furthermore, the researchers conducted a series of tests to evaluate the long-term performance of calcium formate-modified geopolymers. The durability of the materials was assessed under various environmental exposure conditions, such as elevated temperatures and humidity levels. Remarkably, the modified geopolymers exhibited superior resistance to cracking and degradation over time compared to their unmodified counterparts. This resilience suggests that calcium formate could indeed serve as a game-changer in the formulation of fly ash-based geopolymers, potentially extending their applicability in diverse construction scenarios.

An essential aspect of the study involved characterizing the microstructural changes induced by the addition of calcium formate. Advanced analytical techniques, including scanning electron microscopy and X-ray diffraction, were employed to observe the formation of new phases and the densification of the matrix. These results confirmed that the interactions between the fly ash, calcium formate, and water resulted in a more refined and compact microstructure, which correlates with improved mechanical properties.

Sustainability is a key consideration in modern construction practices. By utilizing industrial byproducts like fly ash, the environmental footprint of constructing infrastructure can be substantially reduced. The incorporation of calcium formate as a modifying agent aligns seamlessly with this sustainable agenda by enabling the production of high-performance geopolymers without depending on the extraction of virgin natural resources. This adds value not only to waste materials but also contributes to decreasing carbon emissions associated with traditional cement production.

The implications of this research extend beyond mere technical advancements in the lab. The construction industry is continually under pressure to adopt greener practices, driven by regulations and societal demand for more sustainable solutions. The successful application of modified fly ash geopolymers could revolutionize how concrete is produced and used. By showcasing the potential for recycling waste products and enhancing their capabilities, the study acts as an influential catalyst for change within the industry.

Rashad, Khalil, and Mohamed’s investigation into calcium formate’s role as a modifier agent underscores the excitement surrounding geopolymers in material science. Their findings contribute significantly to our understanding of how additives can enhance the behavior of sustainable materials, pushing the boundaries of what’s currently possible in cement technology. This opens the door for future research into other modifying agents, further enhancing the versatility of geopolymer materials.

The publication of their study in the journal “Environmental Science and Pollution Research” marks an important contribution to the ongoing dialogue about sustainable construction alternatives. It encourages a shift in focus towards integrating innovative materials that not only meet functional requirements but also fulfill ecological obligations. As more researchers and industry stakeholders become aware of the possibilities presented by geopolymers, there is potential for widespread adoption and significant impact on global construction practices.

The study clearly showcases how academic research can directly influence industry practices. By demonstrating the feasibility of enhancing fly ash-based geopolymers with calcium formate, the authors are not just advancing scientific knowledge but are also providing practical solutions to real-world environmental challenges. This combination of innovation and application makes the research highly relevant for ongoing efforts in sustainability and resource efficiency within the construction field.

In conclusion, the research conducted by Rashad, Khalil, and Mohamed highlights the vital role that calcium formate can play as a modifying agent in fly ash-based geopolymer cement. Their findings not only enhance the understanding of geopolymer chemistry but also contribute to the broader objective of sustainable cement production. The implications are profound, suggesting a pathway to more efficient, durable, and environmentally friendly construction practices that could redefine how we approach building materials in the future.

Subject of Research: The use of calcium formate as a modifying agent to enhance fly ash-based geopolymer cement.

Article Title: Calcium formate as a modifier agent for fly ash-based geopolymer cement.

Article References: Rashad, A.M., Khalil, M.H. & Mohamed, R.AE. Calcium formate as a modifier agent for fly ash-based geopolymer cement. Environ Sci Pollut Res (2026). https://doi.org/10.1007/s11356-025-37211-8

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s11356-025-37211-8

Keywords: Fly ash, geopolymer cement, calcium formate, sustainability, construction materials, environmental impact.

Shield slag tailing, formed during the steel manufacturing process, has often been viewed simply as waste. However, recent studies, including those led by researchers Wang, Zhang, and Tan, provide substantial evidence for its viability as a reusable material in construction and infrastructure projects. By exploring state-of-the-art methodologies and innovative practices, stakeholders can capitalize on shield slag tailing’s properties to enhance sustainability efforts, reduce the environmental impact of waste, and create economically viable substitutes for conventional materials.

The environmental implications of ignoring shield slag tailing are profound. In China, where rapid industrialization has led to a staggering accumulation of waste, the challenge remains urgent. Landfill space continues to dwindle, and the adverse effects of industrial waste on the surrounding ecosystems have prompted the need for alternative solutions. Researchers assert that incorporating shield slag tailing into various applications could effectively mitigate these issues by reducing the volume of waste requiring disposal and repurposing it into useful products.

One fascinating aspect of shield slag is its chemical composition, which provides noteworthy engineering properties. The mineralogical characteristics of shield slag tailing contribute to its value as a construction material. For instance, its pozzolanic properties allow it to react with calcium hydroxide and form compounds that can improve the longevity and durability of concrete. Employing this material can enhance the mechanical strength of concrete, making it a more promising alternative to traditional aggregates.

In addition to its physical advantages, using recycled materials like shield slag tailing contributes to the circular economy, supporting initiatives aimed at reducing resources’ overall consumption. By prioritizing the recycling of industrial waste, not only does this practice conserve natural resources, but it also helps industries transform their approaches, paving the way for a more sustainable future. This paradigm shift is what many environmental advocates refer to when they discuss the transition towards a greener economy.

The implementation of shield slag tailing in construction projects is not without its challenges. Researchers emphasize the necessity for extensive testing and data collection to determine optimal usage rates and applications. Studies must focus on understanding how different concentrations of shield slag tailing interact with conventional construction materials like concrete and asphalt. This knowledge is crucial for developing guidelines that ensure performance standards while minimizing potential risks associated with improper use.

Looking ahead, collaborations between governments, research institutions, and industries are paramount to enhancing the reuse of shield slag tailing. Policymakers must recognize the importance of legislating standards that promote recycling initiatives, providing incentives to companies adopting greener practices. Such programs could involve funding for research projects, developing innovative applications for shield slag, or facilitating more comprehensive recycling programs within the industry.

Furthermore, public awareness campaigns can raise consciousness around the benefits of reusing shield slag tailing. By emphasizing its advantages not just for industries but also for the environment, stakeholders can cultivate a collective understanding that prioritizes sustainability. Encouraging community involvement, whether through educational programs or workshops, will help incorporate responsible practices at all levels of society.

Global experiences in recycling practices also provide invaluable insights into the best approaches for implementing shield slag tailing in China. Successful case studies from countries that have embraced waste recycling can serve as models for policymakers and industries to learn from, adopting best practices and tailoring them to suit local contexts. This knowledge-sharing initiative is crucial for ensuring that shield slag achieves its maximum potential impact regarding sustainability.

When it comes to economic benefits, the reuse of shield slag tailing presents an enticing opportunity for cost savings. Industries that incorporate recycled materials often find they can reduce production costs while simultaneously appealing to environmentally conscious consumers. With growing demand for sustainable products, businesses that can pivot towards incorporating innovative materials like shield slag tailing may find themselves at a competitive advantage in the marketplace.

In summary, the misuse of shield slag tailing symbolizes a remarkable opportunity misrepresented as waste. The current status of this material in China underscores its potential in contributing to a sustainable future. Researchers are diligently working to unlock its myriad applications across various sectors, enhancing not only the durability of construction materials but also enriching the fight against environmental degradation. By confronting the challenges head-on and seeking collaborative solutions, we can reshape our industrial landscape, making strides toward a greener and more sustainable existence.

As the journey progresses, ongoing research and evolving techniques will inevitably uncover more profound possibilities for shield slag tailing. The singular focus should be on maximizing its potential while minimizing waste. The transition to widespread reuse of this material might seem daunting, but with the concerted efforts of researchers, industry leaders, and policymakers, a monumental change is within reach, heralding a future where shield slag tailing is no longer seen merely as a waste product but as a cornerstone of sustainable development.

Lastly, it is essential to maintain momentum by continuously revisiting the strategies employed in adopting shield slag tailing within industries. Tracking the long-term benefits, performance improvements, and environmental impacts through comprehensive studies will ensure that this initiative remains relevant and effective over time. The journey into the circular economy may have its complexities, yet the rewards await those willing to innovate and embrace change.

Subject of Research: Reuse of shield slag tailing in China

Article Title: Reuse of shield slag tailing in China: current status and future opportunities

Article References:

Wang, H., Zhang, Z., Tan, J. et al. Reuse of shield slag tailing in China: current status and future opportunities.
Environ Sci Pollut Res (2026). https://doi.org/10.1007/s11356-025-37251-0

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s11356-025-37251-0

Keywords: shield slag tailing, sustainability, recycling, construction materials, environmental impact, circular economy, pozzolanic properties, economic benefits, innovation.

To address this gap, researchers have developed comprehensive testing procedures meant to analyze both the optical and thermal properties of radiative cooling materials, the specific methodologies of which can be adapted for a variety of formats. The first step in this systematic evaluation is to collect hemispherical reflectance and transmittance spectra using advanced equipment. Two integrating sphere spectrometers are employed to capture the solar spectrum, ranging from 0.3 to 2.5 μm, and the infrared spectrum, from 2.5 to 20 μm. This dual-spectrum analysis is accomplished within a span of two hours, laying the groundwork for a more nuanced understanding of how various materials interact with different wavelengths of light.

Following the spectral analysis, attention is shifted to evaluating the materials’ real-world performance. An outdoor performance-testing platform is meticulously designed to monitor temperature variations that arise when materials with distinct radiative cooling capabilities are deployed. Throughout this assessment, thermal insulation and radiation shielding become vital components to ensure accurate readings. Moreover, the setup takes into account various environmental variables, such as humidity, sunlight intensity, wind velocity, and external temperature, all of which play critical roles in the effectiveness of the radiative cooling strategies employed.

While outdoor testing presents a comprehensive approach to understanding these materials, challenges exist in fully replicating the myriad of factors found in uncontrolled environments. This prompted the development of a compact, indoor testing platform, which, although more limited, still serves as a crucial reference point in assessing the performance of radiative cooling materials. By simulating conditions that mimic real-world scenarios, the indoor mechanism facilitates controlled experiments to yield consistent and reproducible results.

An additional layer of sophistication comes into play with the incorporation of a Proportional-Integral-Derivative (PID) temperature control system. This advanced technology allows researchers to manipulate thermal environments more intricately, thereby simulating various application scenarios encountered in actual use cases with higher fidelity. The outdoor evaluations typically extend over a full week, while the indoor assessments can be concluded in just one day, giving researchers immediate access to data that can influence future material development.

Given the complexity of radiative cooling systems, rapid theoretical performance evaluations emerge as a necessity. To this end, a simple MATLAB-based code has been proposed that allows users to engage in swift analytical assessments. Within a mere ten minutes, researchers can glean crucial information regarding the potential effectiveness of new materials, thus accelerating the overall development process.

The importance of standardizing the evaluation of radiative cooling materials cannot be overstated. As markets for energy-efficient technologies gain traction globally, having a dependable method to assess materials will not only enhance competition but also stimulate innovation within this sector. By making these procedures accessible, researchers can collaborate more effectively, sharing insights and advancements that could lead to revolutionary improvements in radiative cooling applications.

Moreover, the implications extend beyond just technical evaluations; there is an inherent potential for broad societal benefits. In urban areas laden with heat islands, the implementation of radiative cooling technologies can lead to significant energy savings and lower electric bills, ultimately contributing to reduced greenhouse gas emissions. The widespread adoption of such materials can transform public infrastructure into sustainable entities that work in tandem with natural processes.

As scientists delve deeper into the world of radiative cooling, the anticipation surrounding new discoveries remains palpable. Innovations are expected to emerge that do not only enhance cooling efficiency but also utilize waste heat for other beneficial purposes. By marrying technology and sustainability, the radiative cooling frontier stands poised to redefine modern architecture, energy consumption, and environmental stewardship.

Researchers stand on the brink of unlocking a vast potential with radiative cooling materials. As protocols for testing and evaluating these materials become more refined, the pathway to commercial applications will inevitably become clearer. The bright future for sustainable technological advancements, rooted in rigorous research and collaborative effort, continues to illuminate possibilities for a more energy-efficient and environmentally conscious world.

Fundamentally, the drive towards sustainable solutions including radiative cooling techniques is a crucial stride towards addressing climate change and environmental sustainability. As we invest in and explore the capabilities of these innovative materials, it becomes evident that the journey of harnessing the sun’s power for cooling applications is just beginning. With a combination of strategic research, rigorous testing, and community collaboration, a renaissance in energy efficiency driven by radiative cooling seems not only plausible but probable.

Subject of Research: Radiative cooling materials and their performance evaluation methods.

Article Title: Characterization of radiative cooling materials.

Article References:

Wang, Z., Pian, S. & Ma, Y. Characterization of radiative cooling materials. Nat Protoc (2025). https://doi.org/10.1038/s41596-025-01273-2

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41596-025-01273-2

Keywords: Radiative cooling, thermal properties, optical properties, performance evaluation, sustainable materials.

The findings, detailed in a recent publication in the esteemed journal Science Advances, showcase how this novel carbon nanofiber direct air capture (DAC) filter can be seamlessly integrated into existing infrastructures, offering a practical solution for both residential and commercial properties. This innovation signifies a major leap toward mitigating the accumulation of airborne carbon dioxide, a significant contributor to climate change.

The collaborative research, spearheaded by Assistant Professor Po-Chun Hsu at UChicago PME, presents a comprehensive life-cycle analysis of the new filter, revealing an impressive efficiency rate of 92.1% in capturing carbon dioxide. This statistic takes into account the entire lifecycle of the filter, from its creation to disposal, thus ensuring that the environmental impact remains overwhelmingly positive even after considering the carbon dioxide emissions associated with its manufacture, transportation, and maintenance.

Ronghui Wu, the first author of the study, accentuates the practical advantages of this technology. He notes that buildings inherently possess ventilation systems that continuously circulate large volumes of air. By integrating the new DAC filters into these existing systems, homeowners and building managers could effectively capture carbon directly from their environments without the necessity for the construction of new carbon capture facilities or consumption of additional land, truly making this technology practical and scalable.

The implications of widespread adoption of these filters are staggering, with an estimated potential for the removal of up to 596 megatonnes of carbon dioxide from the atmosphere if every building worldwide replaced its conventional air filters with the new carbon nanofiber model. To put this into perspective, this level of carbon capture is equivalent to eliminating the carbon footprint of approximately 130 million vehicles for one year.

Moreover, the adoption of DAC filters isn’t solely a boon for environmental health; it also presents economic advantages for individual users. Early studies indicate that transitioning to these innovative filters may lead to energy bill reductions of up to 21.66%. Wu explains that conventional air-conditioning systems often struggle to manage indoor air quality due to the need for inflowing outside air to dilute internal carbon levels. The new filters adeptly remove the carbon dioxide generated indoors, thus minimizing the requirement for additional outside air and significantly cutting down on the energy expended in heating or cooling.

A particularly striking aspect of this development is the ability of the filters to regenerate their carbon-capturing capabilities using solar energy. Traditional direct air capture methods are often massive operations, reliant on substantial investments in land and energy. Hsu draws a parallel between this innovation and the evolution of solar energy utilization, where solar technology has expanded from large utility fields to smaller, decentralized rooftop panels. The adaptability of carbon capture filters to individual buildings aligns with contemporary demands for sustainable and efficient energy solutions.

The cutting-edge material used in these filters, carbon nanofiber with polyethylenimine, allows for reusable functionality. This benefit starkly contrasts with conventional high-efficiency particulate air (HEPA) filters, which require disposal every six months to a year, contributing to waste. The proposed carbon capture filters, on the other hand, can be periodically rejuvenated and reinserted into the HVAC systems, creating a sustainable cycle that promotes carbon removal and reduces landfill contributions.

The envisioned process for managing these filters emphasizes community involvement and sustainability. Wu and Hsu propose a system whereby municipal waste management effectively coordinates the collection of used filters, which would then be transported to centralized facilities designed for the extraction and management of the captured carbon. This operation not only promotes the recycling of materials but also facilitates the conversion of captured CO2 into high-value chemicals or fuels, further enhancing the economic viability of this approach.

One of the noteworthy features of the new material is its remarkable solar absorptivity, which allows for the efficient removal of CO2 through solar thermal methods. Hsu notes that regenerating the filters with renewable energy sources like sunlight negates the potential for increased emissions that can result from traditional heating methods reliant on fossil fuels. This holistic consideration underscores the commitment of the research team to ensuring the overall sustainability of their technology.

Furthermore, the advantages extend beyond environmental and economic aspects, as the direct air capture filters can significantly enhance indoor air quality. For settings such as classrooms and offices, where groups of individuals congregate in close quarters, maintaining lower levels of carbon dioxide through effective filtration has the potential to improve focus and productivity. This multifaceted benefit showcases the filters not just as a technological advancement but as a means to promote healthier environments for everyday life.

As the world increasingly acknowledges the urgency of addressing climate change, technologies like these carbon nanofiber air filters represent vital steps in the ongoing quest for practical solutions. By leveraging existing infrastructure and enabling the decentralized capture of carbon efficiently, this innovative approach illuminates a path forward—a path where every building contributes to a healthier, more sustainable planet.

The collaboration and dedication demonstrated by the UChicago PME team serve as a stimulative example of how academic research can translate into groundbreaking real-world applications, ultimately shaping a future where carbon capture technology becomes an integral aspect of daily life, compelling emissions decreases not just on a global scale but also within local communities.

Subject of Research: Development of a Nanofiber Air Filter for Carbon Capture
Article Title: Distributed Direct Air Capture by Carbon Nanofiber Air Filters
News Publication Date: October 17, 2025
Web References: Science Advances
References: Wu et al., Science Advances, 2025
Image Credits: University of Chicago Pritzker School of Molecular Engineering

Keywords

Carbon capture, climate change, direct air capture, renewable energy, indoor air quality.