The researchers built the composite around high-calcium fly ash collected from the Mae Moh coal-fired power plant in Lampang, Thailand. Fly ash is a fine industrial residue whose glassy aluminosilicate phases can be chemically dissolved and reorganized into a hardened inorganic binder. X-ray fluorescence analysis showed that the ash contained 45.23 percent silicon dioxide, 19.94 percent aluminium oxide and 15.50 percent calcium oxide, along with iron, magnesium and smaller quantities of other oxides. Microscopy revealed mostly spherical particles, which can act like tiny ball bearings and improve the workability of fresh mixtures. X-ray diffraction identified a broad amorphous halo—evidence of reactive glass—together with crystalline quartz, mullite, magnetite, hematite and free lime. The ash was classified as a Class F pozzolan under ASTM standards, but its relatively high calcium content gave it a more complex reaction pathway than low-calcium fly ash.

To activate the ash, the team combined sodium hydroxide with liquid sodium silicate, replacing freshwater entirely with untreated seawater collected from the Gulf of Thailand near Chonburi. The seawater contained dissolved sodium and chloride as its dominant ions, as well as sulfate, magnesium, potassium and calcium. These ions are not chemically passive spectators. In an alkali-activated binder, hydroxide ions attack the glassy aluminosilicate structure, releasing silicon and aluminium into solution. Those species then polymerize into a three-dimensional sodium aluminosilicate hydrate, or N-A-S-H, network. Calcium from the fly ash and Portland cement can simultaneously promote calcium silicate hydrate and calcium aluminosilicate hydrate, commonly written as C-S-H and C-A-S-H. The resulting hybrid gel structure can harden at room temperature, while chloride and sulfate ions from seawater alter dissolution, precipitation and setting reactions.

The solid binder contained 90 percent fly ash and 10 percent ordinary Portland cement. That small cement addition was designed to provide extra reactive calcium and improve early strength and setting under ambient conditions without displacing the predominantly waste-derived binder. River sand supplied the fine mineral skeleton, while mechanically crushed expanded polystyrene, or EPS, replaced part of the denser matrix. The recycled particles measured between 2.36 and 4.75 millimetres and had a bulk density of only 26.84 kilograms per cubic metre. EPS is mostly closed-cell polymer foam, so it contributes little mass while trapping air—an arrangement that can slow heat flow through a wall. The researchers tested five EPS contents, from 0.80 to 1.60 percent of total binder mass, and compared activators containing either 5-molar or 10-molar sodium hydroxide.

The central surprise was that the lower-alkalinity mixture performed better. In conventional freshwater geopolymer systems, increasing sodium hydroxide concentration often improves precursor dissolution and compressive strength. The researchers therefore treated 10 molar sodium hydroxide as a conventional benchmark. But seawater changed the balance. At high alkalinity, the combination of hydroxide, chloride, sulfate and magnesium accelerated reactions so aggressively that the paste began to coagulate before it could be properly mixed and compacted around the hydrophobic EPS particles. This rapid setting trapped large air voids and disrupted the formation of a continuous binder network. By contrast, the 5-molar seawater activator slowed the reaction enough for the aluminosilicate network and calcium-rich gels to develop more evenly, producing a denser and stronger microstructure.

The best mechanical result came from the 5M-E0.80 mixture, containing 0.80 percent EPS and the 5-molar seawater-based activator. After 28 days of sealed ambient curing at approximately 25 degrees Celsius, it reached 26.8 megapascals. That is above the commonly cited threshold of 17 megapascals for structural lightweight concrete and exceeds the 13.1-megapascal minimum referenced for load-bearing lightweight masonry units. Increasing EPS content progressively reduced strength: in the 5-molar series, the 28-day value fell from 26.8 megapascals at 0.80 percent EPS to 9.6 megapascals at 1.60 percent. The polymer particles behave as soft inclusions rather than load-bearing aggregate. Under compression, stress concentrates around their boundaries, where the chemically incompatible interface can initiate microcracks. The 10-molar series was weaker at every EPS dosage; at 0.80 percent EPS, it reached 19.5 megapascals, about 27 percent below the matching 5-molar specimen.

The same pores that weakened the most highly expanded mixtures also gave the material functional advantages. In the 5-molar samples, increasing EPS from 0.80 to 1.60 percent raised apparent porosity from 34.8 to 53.6 percent and water absorption from 1.92 to 5.74 percent. EPS itself does not absorb water, but its water-repellent surface forms a weak interfacial transition zone with the surrounding hydrophilic paste. That boundary can create interconnected capillary pathways. Thermal conductivity declined as EPS content increased, reaching 0.387 watts per metre-kelvin in the most porous 10-molar mixture at 1.60 percent EPS. However, that sample suffered a major loss of strength. The more useful compromise was again 5M-E0.80, which combined 26.8 megapascals of compressive strength with a thermal conductivity of 0.718 watts per metre-kelvin.

The composite also displayed measurable acoustic performance. Using an impedance tube, the researchers examined sound absorption between 400 and 2,500 hertz. Most mixtures recorded absorption coefficients between 0.05 and 0.20, higher than the value below roughly 0.05 typical of dense concrete. The strongest response came from the 5M-E1.20 formulation, which reached a peak absorption coefficient of 0.358 near 500 hertz. The 5M-E0.80 sample reached 0.220 at the same frequency, while the best 10-molar mixture peaked at only 0.189. Sound absorption in the material arises as air motion enters pores and narrow channels, generating viscous friction that converts acoustic energy into heat. The researchers argue that controlled reaction kinetics in the 5-molar system preserve a tortuous network of micro-capillaries, whereas rapid setting in the 10-molar mixture creates irregular macropores that are less effective at dissipating sound.

The study presents a striking sustainability package: coal ash is diverted from waste storage, EPS packaging is reused, freshwater is removed from the mix and no elevated-temperature curing is required. Yet the material’s advantages come with important boundaries. Raw seawater introduces a high chloride load, making conventional steel reinforcement vulnerable to corrosion even if some chloride becomes chemically bound within the alkaline matrix. Near-term applications would therefore be limited to unreinforced blocks, precast wall elements, insulating façade panels and other plain-concrete components, or to structures using corrosion-resistant reinforcement such as fibre-reinforced polymer bars. The experiments also covered only one- and 28-day strength, leaving long-term questions about creep, drying shrinkage, efflorescence, fire behaviour, freeze–thaw resistance and degradation of the EPS interface unresolved. The results are consequently best viewed not as a ready-made replacement for all concrete, but as evidence that carefully tuned seawater chemistry can turn problematic wastes into a structural-grade, multifunctional building material.

Bamboo, known for its rapid growth and mechanical resilience, generates substantial byproducts during industrial processing. Approximately 35% to 50% of bamboo biomass becomes waste, often relegated to landfill or incineration, thereby representing a significant underutilized resource. Repurposing these residues not only addresses environmental disposal concerns but also opens pathways to creating high-performance building materials that align with circular economy principles. The study centers on this rationale, aiming to transform bamboo scraps into valuable composite components within magnesium oxychloride cement (MOC) matrices.

MOC itself is attracting renewed attention as a low-carbon alternative to conventional Portland cement. Unlike Portland cement, which requires energy-intensive calcination processes and emits large quantities of CO2, MOC forms through reactions involving magnesium oxide and magnesium chloride at relatively low temperatures, yielding a cementitious material with a fraction of the carbon footprint. However, MOC suffers from characteristic drawbacks, notably its brittleness and moisture sensitivity, which have historically constrained its widespread use in construction scenarios demanding durability and toughness.

Addressing these limitations necessitates innovative strategies to improve composite toughness and moisture resistance while preserving insulating properties. This recent investigation proposes a mild chemical modification of bamboo scraps through ammonium carbonate treatment prior to their incorporation into the MOC matrix. Diverging from conventional strong alkali treatments, which aggressively degrade fiber structures and create toxic effluents, this gentle method selectively removes non-cellulosic components such as lignin and hemicellulose, preserving the primary cellulose fibers critical for mechanical reinforcement.

This carefully balanced chemical modulation imparts dual benefits within the composite system. First, the treatment softens the rigid bamboo fibers’ structure, mitigating their disruptive effect on pore formation during foam composite fabrication. The rigidity of untreated fibers often leads to pore collapse and uneven distribution, which in turn generate stress concentration points prone to mechanical failure. Second, the exposure of hydrophilic groups on the bamboo fiber surface fosters enhanced chemical affinity and bonding between the organic fibers and the inorganic MOC matrix.

On a microstructural level, the ammonium carbonate-treated bamboo facilitates the growth of needle-like magnesium oxychloride crystalline phases that penetrate fiber surface micropores, effectively “anchoring” the organic and inorganic phases together. This interfacial bonding mechanism significantly augments composite toughness and mechanical coherence. Electron microscopy images reveal that untreated bamboo fibers disrupt foam pore morphology, leading to irregular and compromised cellular structures. Conversely, treated fibers sustain pore integrity, promoting homogeneously distributed pores throughout the composite volume.

The enhanced pore architecture contributes substantially to both mechanical and thermal performance. Uniform pores reduce localized stress concentrations and overall composite brittleness while simultaneously restricting conduction pathways for heat transfer, yielding improved insulation characteristics. Quantitative performance evaluation under optimized treatment parameters demonstrated a remarkable 45% increase in compressive strength, an enhancement in the softening coefficient by 12%, and a 15% reduction in thermal conductivity compared to untreated bamboo composites. These concurrent improvements underscore the feasibility of balancing lightweight structural strength with effective thermal insulation, a critical requirement for modern energy-efficient buildings.

Beyond mechanical and thermal gains, the environmental footprint of the treatment process was also assessed. The ammonium carbonate approach yields wastewater with significantly reduced chemical oxygen demand (COD) relative to traditional sodium hydroxide treatments, lessening water pollution risks. Moreover, residual ammonia from the reaction can be captured and recycled as agricultural fertilizer, exemplifying a closed-loop process that enhances resource efficiency and minimizes industrial waste streams.

In synthesizing these findings, the research delineates a sustainable pathway for valorizing bamboo processing residues into high-quality building materials that effectively integrate organic fibers with inorganic cement matrices. This advancement marks a significant stride toward overcoming the compatibility challenges inherent in biomass-cement composites and aligns with global imperatives to decarbonize the construction sector without compromising material performance.

Potential practical applications for the developed composites encompass thermal insulation panels, structural fillers, and fire-resistant building components. Each of these serves critical roles in reducing energy consumption, optimizing resource use, and improving safety in residential and commercial constructions. By harnessing agricultural waste and environmentally benign chemical treatments, this work lays the groundwork for novel materials that could reshape sustainable architecture and civil engineering paradigms.

The broader implications of this research underscore the transformative potential of moderate chemical treatments applied judiciously to biomass resources. By preserving essential fiber structures while enhancing interfacial adhesion with mineral phases, such methodologies can unlock new avenues for composite materials that combine ecological responsibility with high mechanical and thermal functionality.

Future research directions may probe the scalability of the ammonium carbonate treatment process in industrial settings, investigate long-term durability under various environmental stresses, and explore integration with other low-carbon cementitious materials. Additionally, life cycle analyses and techno-economic assessments will be crucial to validating the commercial viability and environmental advantages of these composites on a broad scale.

In summary, light chemical component modulation of bamboo scraps emerges as a compelling strategy to enhance interfacial compatibility and strength in thermal insulation composites, exemplifying how innovative material science can contribute to sustainable construction technologies with global impact.

Subject of Research: Not applicable

Article Title: Light Component Modulation of Bamboo Scraps Enhances Interfacial Compatibility and Strength of Thermal Insulation Composites

News Publication Date: 15-Apr-2026

Web References:
Journal of Bioresources and Bioproducts
DOI: 10.1016/j.jobab.2026.100252

Image Credits: School of Materials and Energy, Central South University of Forestry and Technology, Changsha 410004, China

Keywords

Bamboo, biomass, magnesium oxychloride cement, interfacial bonding, thermal insulation composites, sustainable construction, chemical modification, ammonium carbonate treatment, pore structure, composite materials, low-carbon cement, mechanical strength

Dr. Shuang (Cynthia) Cui, an assistant professor in the Erik Jonsson School of Engineering and Computer Science, emphasizes that this technology addresses one of the critical challenges in modern architecture: creating comfortable indoor environments without placing excessive demands on power grids. The phase-change material used in this construction dramatically enhances thermal energy storage capabilities, enabling buildings to better leverage natural heat sources. The implications of this research extend beyond mere comfort; they reach into the heart of energy sustainability.

The collaboration among researchers at UT Dallas and various prestigious institutions, including the National Renewable Energy Laboratory and the University of California, Berkeley, has culminated in a study that showcases not only the effectiveness of the new material but also its durability. Published in the December issue of the peer-reviewed journal Materials Today Energy, this study contributes to the understanding of how composite materials can be optimized for performance in thermal energy applications.

The innovative wood-based thermal battery incorporates phase-change materials that undergo transformations between solid and liquid states. As the material melts, it absorbs heat, and conversely, when it solidifies, it releases stored heat. This cyclical energy process provides a passive means to regulate indoor temperatures, particularly in climates where heating and cooling demands fluctuate throughout the year. The application of such materials in drywall, flooring, or roofing could minimize peaks in energy consumption and lower overall carbon footprints.

Bernadette Magalindan, a mechanical engineering doctoral student and a member of Dr. Cui’s research team, notes that this technology exemplifies the potential of thermal energy storage. By harnessing excess heat from the environment, the material can moderate temperature extremes. For instance, it can absorb heat during the day to keep spaces cooler, thus reducing the need for air conditioning. This innovative approach not only enhances occupant comfort but also provides a compelling solution for reducing energy costs in residential and commercial buildings.

One of the notable challenges with traditional phase-change materials is their tendency to leak during the phase transition from solid to liquid, which poses significant barriers to their practical application. To mitigate this issue, the researchers opted to refine the wood structure, stripping lignin away to create a porous, spongelike network that can encapsulate the PCM while preventing leakage. By integrating a soft plastic component that stabilizes the phase-change material even at high temperatures, they have greatly enhanced the efficacy of the composite.

Through rigorous testing, the new material demonstrated remarkable durability, sustaining more than 1,000 phase-change cycles without degradation or leakage. Dr. Hongbing Lu, another co-author of the study, highlighted the mechanical advantages of this energy-storage composite. Unlike many existing materials that sacrifice structural integrity for increased energy storage, the wood-templated composite maintains robustness, ensuring it can withstand the rigors of real-world use in building applications.

The findings from this research have significant ramifications for the future of energy-efficient architecture. By embedding phase-change materials into building designs, architects and builders can create structures that are not only more environmentally friendly but also economically sustainable. With energy efficiency being a hot topic in the construction industry, this innovation serves as a practical solution to ongoing challenges related to energy demand management, offering a dual approach to residential and commercial energy needs.

The project, supported by collaboration from the National Renewable Energy Laboratory and several universities, speaks to the importance of interdisciplinary approaches in addressing global sustainability challenges. The researchers envision this wood-based thermal energy storage system as a transformative element in the construction industry, with the potential to minimize both energy costs and greenhouse gas emissions.

Looking forward, the UT Dallas team plans to further refine and commercialize this technology. As the conversation around sustainability in building practices continues to grow, innovative solutions such as this wood-based thermal battery can lead to a paradigm shift in how we think about energy storage and consumption in our living and working spaces.

Ultimately, the work being conducted at UT Dallas illustrates how scientific inquiry and collaborative effort can converge to create sustainable solutions for pressing global issues, setting the stage for future advancements in energy-efficient building technologies. With ongoing research and development, the potential applications of this thermal battery technology could effectively pave the way for smarter energy management in architecture and beyond.

As the world grapples with climate change and seeks effective methods to minimize carbon footprints, innovations like the wood-based thermal battery offer a beacon of hope. With practical applications that promise widespread benefits, the collective efforts of researchers can lead the way towards a more sustainable future in global energy consumption and building practices.

Subject of Research: Development of a wood-based thermal energy storage system using phase-change materials.
Article Title: Wood template-supported phase change material composites for durable and form-stable thermal energy storage in buildings.
News Publication Date: 1-Dec-2025.
Web References: ScienceDirect Materials Today Energy
References: Not applicable.
Image Credits: The University of Texas at Dallas.

Keywords

Sustainable development, thermal energy storage, phase-change materials, energy efficiency, building technology, engineering, architecture, mechanical engineering, renewable energy solutions, environmental science, construction engineering, innovative materials.

One groundbreaking development emerging from this urgent need is the Colloidal Silica Recovered from Geothermal Fluids (CSRGF) grout, an innovation from a research team at the Shibaura Institute of Technology in Japan. This novel grout not only enhances soil stabilization but also utilizes byproducts from geothermal energy production, effectively minimizing the associated carbon footprint. The ingenious application of these geothermal byproducts demonstrates a significant shift in how we can leverage existing waste materials for cutting-edge construction practices.

Professor Shinya Inazumi, who leads the research team, emphasizes that this new grout exemplifies a circular economy approach. Instead of treating waste fluids generated during geothermal energy production as mere disposal challenges, the research team has creatively turned them into a beneficial building material. This forward-thinking vision not only addresses environmental sustainability but also promotes resource efficiency, showing how innovative engineering can serve dual purposes—ground improvement and waste reduction simultaneously.

The CSRGF grout not only promises to be environmentally friendly but also exhibits mechanical properties that surpass many conventional grouting materials. Laboratory tests indicate a remarkable increase in liquefaction resistance, estimated at 50% greater than existing options. Such enhancements significantly bolster structural integrity, particularly in earthquake-prone regions where the stability of buildings and infrastructure is paramount.

Furthermore, the low viscosity of CSRGF grout allows for deep soil penetration, ensuring that it reaches the areas that require the most stabilization. Controlled gelling times also provide flexibility in application, ensuring that construction teams can work efficiently. These qualities make CSRGF not merely an alternative but a preferred option for engineers seeking to enhance soil conditions while following stringent environmental guidelines.

The versatility of this grout extends beyond just earthquake preparedness. Its excellent water-sealing capabilities make it suitable for various underground construction applications, like tunnels, subways, and basements, where water infiltration presents a considerable challenge. Such capabilities are increasingly vital in regions prone to flooding and rising sea levels, demonstrating the material’s potential contributions to resilient infrastructure.

In light of these advancements, the adoption of CSRGF grout advocates for a paradigm shift in the construction industry, moving towards greater integration of sustainable practices. Not only does this innovation provide a means to significantly lower CO2 emissions during construction, but it also establishes new industry standards for environmentally responsible ground stabilization. The potential to align construction methods with international sustainability initiatives positions CSRGF grout as a frontrunner in the quest for carbon neutrality by 2050.

An essential component of the future development of CSRGF grout involves scaling up its production while simultaneously conducting rigorous field trials. These field tests are crucial for verifying the grout’s performance under real-world conditions, ensuring that its advantages observed in laboratory settings translate effectively to practical applications. As the pressure mounts for construction companies to adopt greener technologies, the urgency for reliable and tested materials increases correspondingly.

The innovative nature of this research stems from a comprehensive understanding of both environmental challenges and engineering necessities. By repurposing waste products and transforming them into high-performance materials, the research team demonstrates that sustainability and effectiveness can coexist in construction practices. This breakthrough not only serves immediate construction needs but also aligns within the broader context of global efforts to address climate change.

As the construction industry navigates its way towards more sustainable practices, the CSRGF grout presents a compelling case for future studies and applications. The ingenuity behind its development showcases how interdisciplinary approaches combining environmental science and engineering can forge remarkable solutions to pressing issues. Therefore, the landscape of construction materials is evolving, shifting towards methods that prioritize both functionality and environmental stewardship.

Moving forward, the collaborations between researchers, industry professionals, and policymakers will play a crucial role in mainstreaming such innovations. By working together, these stakeholders can create ecosystems that support sustainable material development, ultimately helping to forge a greener future for the construction industry as a whole. The journey towards carbon neutrality will require collective effort and commitment across various sectors, with innovations like CSRGF grout leading the way toward a more sustainable infrastructure.

Subject of Research: Geothermal-derived silica grout for soil stabilization.
Article Title: Development and application of geothermally derived silica grout for carbon-neutral soil stabilization.
News Publication Date: January 22, 2025.
Web References:
References:
Image Credits: Shinya Inazumi from Shibaura Institute of Technology, Japan.
Keywords: Sustainable construction, grouting technology, carbon-neutral materials, geothermal energy, soil stabilization, environmental innovation, circular economy, earthquake resistance, waste management, resilient infrastructure, eco-friendly materials, engineering advancements.