Search Results (694)

Alkali-activated materials (AAMs) offer a promising low-carbon alternative to Portland cement, but their development has been dominated by fly ash and slag, whose availability is increasingly limited. This research explores waste brick powder (WBP) and metakaolin residue (RN), two abundant yet underutilized by-products, as blended precursors for sustainable binder design. The novelty lies in demonstrating how complementary chemistry between crystalline-rich WBP and amorphous RN can overcome the drawbacks of single-precursor systems while valorizing construction and industrial residues. Pastes were prepared with varying WBP/RN ratios, activated with alkaline solutions, and characterized by Vicat setting tests, isothermal calorimetry, XRD with Rietveld refinement, MIP, SEM, and mechanical testing. Carbon footprint analysis was performed to evaluate environmental performance. Results show that WBP reacts very rapidly, causing flash setting and limited long-term strength, whereas the incorporation of 30–50% RN extends setting times, sustains dissolution, and increases amorphous gel formation. These changes refine the formed reaction products, leading to compressive strengths up to 39 MPa and flexural strengths of 8 MPa at 90 days. The carbon footprint of all blends remained 392–408 kg CO₂e/m³, thus providing about a 60% improvement compared to conventional Portland cement paste. The study establishes clear design rules for waste-derived blended precursors and highlights their potential as circular, low-carbon binders. Full article

Accelerated artificial aging of zinc oxide (ZnO)-based acrylic artists’ paint, filled with calcium carbonate (CaCO₃) as an extender, was carried out for a total of 1963 h (~8 × 10⁷ lux·h), with assessments at specific intervals. The total color difference ΔE* was <2 (CIELab-76 system) over 1725 h of aging, while the human eye notices color change at ΔE* > 2. Oxidative degradation of organic components in the paint to form volatile products was revealed by attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). It appears that deep oxidation of organic intermediates and volatilization of organic matter may be responsible for the relatively small value of ΔE* color difference during aging of the samples. To elucidate the degradation pathways, principal component analysis (PCA) was applied to the spectral data, revealing: (1) the catalytic role of ZnO in accelerating photodegradation, (2) the Kolbe photoreaction, (3) the decomposition of the binder to form volatile degradation products, and (4) the relative photoinactivity of CaCO₃ compared with ZnO, showing slower degradation in areas with a higher CaCO₃ content compared with those dominated by ZnO. These results provide fundamental insights into formulation-specific degradation processes, offering practical guidance for the development of more durable artist paints and conservation strategies for acrylic artworks. Full article

Global urbanization has led to massive generation of high-water-content waste slurry, creating serious environmental challenges. Conventional treatment methods are costly and unsustainable, while cement-based foamed lightweight soils typically exhibit low strength and limited CO₂ sequestration. To address this issue, this study proposes a novel stabilization pathway by integrating a MgO–mineral powder–carbide slag composite binder with CO₂ foaming–carbonation. The approach enables simultaneous slurry lightweighting, strength enhancement, and CO₂ fixation. A series of laboratory tests were conducted to evaluate flowability, density, compressive strength, and deformation characteristics of the carbonated lightweight stabilized slurry. Microstructural analyses, including SEM and XRD, were used to reveal the formation of carbonate phases and pore structures. The results showed that MgO content strongly promoted carbonation, leading to denser microstructures and higher strength, while mineral powder and carbide slag optimized workability and pore stability. Orthogonal testing indicated that a mix with 25% mineral powder, 12.5% MgO, and 7.5% carbide slag achieved the best performance, with unconfined compressive strength up to 0.48 MPa after carbonation. Compared with conventional cement- or GGBS-based foamed lightweight soils, the proposed system exhibits superior strength development, improved pore stability, and enhanced CO₂ sequestration potential. These findings demonstrate the feasibility of recycling high-water-content waste slurry into value-added construction materials while contributing to carbon reduction targets. This study not only provides a sustainable solution for waste slurry management but also offers new insights into the integration of CO₂ mineralization into geotechnical engineering practice. Full article

The present study aims to develop 3D-structured adsorbents for carbon capture with the utilization of coal ash after its conversion into zeolites. For this purpose, printing paste mixtures with a viscosity of 800 Pa·s were developed based on an environmentally friendly and safe polymer binder filled with coal ash zeolite with the addition of bentonite as a filler. The optimal consistency of the printing mixtures for preserving the shape and dimensions of the 3D-printed structures was established. Various model configurations of the macrostructure of 3D adsorbents were developed, and the optimal settings of the extruding system for their printing were established. After calcination, the resulting 3D structures were studied using instrumental analysis techniques, investigating the influence of 3D structuring on the phase composition, surface characteristics, and adsorption capacity for CO₂ capture in comparison with the initial powder coal ash zeolite adsorbents. The role of compensating cations in terms of the adsorption ability of powders in 3D-printed adsorbents was investigated. The current study offers an innovative and previously unexplored approach to a more expedient and practically significant utilization of aluminosilicate solid waste and, in particular, coal ash, through their 3D structuring and outlines a new research and technological direction in the development of economically advantageous, technologically feasible, and environmentally friendly 3D adsorbents. Full article

With the low-carbon transformation of the steel industry, using low-carbon raw materials is one of the important ways to achieve the “dual carbon” goals. Pellets have great physical and chemical properties as low-carbon furnace materials, which can significantly reduce blast furnace carbon emissions, exhibiting favorable overall environmental benefits. Increasing their proportion in the furnace is one of the important measures the steel industry can take to reduce carbon emissions. Binders play a critical role in the pelletizing process, and their properties directly influence pellet quality, thereby affecting the subsequent blast furnace smelting process. Compared with traditional bentonite, organic binders have become a potential alternative material due to their environmental friendliness, renewability, and ability to significantly reduce silica and alumina impurities in pellets while improving the iron grade. This work systematically elucidates the mechanism of organic binders, which primarily rely on the chemical adsorption of carboxyl groups and the hydrogen bonding of hydroxyl groups to enhance pellet strength, and then provides three typical examples of organic binders: lignosulfonate, carboxymethyl cellulose (CMC), and carboxymethyl starch (CMS). The common characteristic of these organic binders is that they are derived from renewable biomass through chemical modification, which is a derivative of biomass with renewable and abundant resources. However, the main problem with organic binders is that they burn and decompose at high temperatures. Current research has achieved technological breakthroughs in pellet quality by combining LD sludge, low-iron oxides, and nano-CaCO₃, including improved iron grade, reduced reduction swelling index (RSI), and enhanced preheating/roasting strength. Future studies should focus on optimizing the molecular structure of organic binders by increasing the degree of substitution of functional groups and the overall degree of polymerization. This approach aims to replace traditional bentonite while exploring applications of composite industrial solid wastes, effectively addressing the high-temperature strength loss issues in organic binders and providing strong support for the steel industry to achieve the green and low-carbon goals. Full article

The applicability of biochar as a coarse aggregate substitute in concrete to increase sustainability and multifunctionality was investigated. Biochar, a porous carbon-rich byproduct from biomass pyrolysis, was incorporated at various replacement ratios (5–20%) under four water-to-binder (w/b) conditions (0.25–0.40). The key physical, mechanical, thermal, and microstructural properties, including the unit weight, porosity, compressive strength, flexural strength, and thermal conductivity, were evaluated via SEM and EDS analyses. The results revealed that although increasing the biochar content reduced the mechanical strength, it significantly improved the thermal insulation performance because of the porous structure of the biochar. At low w/b ratios and 5–10% biochar content, sufficient mechanical properties were retained, indicating a viable design range. Higher replacement ratios (>15%) led to excessive porosity, reduced hydration, and impaired durability. This study quantitatively analyzed the interproperty correlations, confirming that the strength and thermal performance are closely linked to the internal matrix density and porosity. These findings suggest that biochar-based concrete has potential for use in thermal energy storage systems, high-temperature insulation, and low-carbon construction. The low-carbon effect is achieved both by sequestering stable carbon within the concrete matrix and by partially replacing cement, thereby reducing CO₂ emissions from cement production. Moreover, the results highlight a strong correlation between increased porosity, enhanced thermal insulation, and reduced strength, thereby offering a solid foundation for sustainable material design. In particular, the term ‘high temperature’ in this context refers to exposure conditions above approximately 200~400 °C, as reported in previous studies. However, this should be considered as a potential application to be validated in future experiments rather than a confirmed outcome of this study. Full article

Fruit production is a high environmental impact sector, requiring sustainable strategies that reduce greenhouse gas (GHG) emissions, improve resource efficiency, and maintain fruit quality. This study assessed the environmental performance of innovative substrates with biodegradable additives and organic binders in tunnel-grown raspberry production. The functional unit was 1 kg of marketable fruit, and the experiment was conducted in Karwia, Poland. GHG emissions were calculated for eight substrate variants following ISO 14040 and 14041 guidelines. The baseline was coconut fiber, while modified variants included the additions of sunflower husk biochar and/or a wood-industry isolate, representing sustainable strategies in soilless cultivation. Emissions ranged from 0.728 to 1.226 kg CO₂ eq/kg of raspberries, with the control showing the highest values. All modified substrates (produced based on a mixture of biochar and isolate) reduced emissions, with the most efficient variant achieving nearly a 40% decrease. Water use efficiency was decisive, as consumption declined from 2744 m³/ha (control) to 1838 m³/ha in improved variants. Substrate air–water properties proved critical for both environmental and economic outcomes. The findings confirm that substrate modification constitutes an effective, sustainable strategy for raspberry production under high tunnels, supporting climate-smart horticulture and resource-efficient food systems. Full article

Coffee processing generates large volumes of spent coffee grounds (SCGs), which contain 30–40% hemicellulose, 8.6–13.3% cellulose, and 25–33% lignin, making them a promising lignin-rich filler for biocomposites. Conventional wood composites rely on urea-formaldehyde (UF), melamine–urea–formaldehyde (MUF), and phenol–formaldehyde resins (PF), which dominate 95% of the market. Although formaldehyde emissions from these resins can be mitigated through strict hygiene standards and technological measures, concerns remain due to their classification as category 1B carcinogens under EU regulations. In this study, fiber-based biocomposites were fabricated from thermomechanical wood fibers, SCGs, and ammonium lignosulfonate (ALS). SCGs and ALS were mixed in a 1:1 ratio and incorporated at 40–75% of the oven-dry fiber mass. Hot pressing was performed at 150 °C under 1.1–1.8 MPa to produce panels with a nominal density of 750 kg m⁻³, and we subsequently tested them for their physical properties (density, water absorption (WA), and thickness swelling (TS)), mechanical properties (modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond (IB) strength), and thermal behavior and biodegradation performance. A binder content of 50% yielded MOE ≈ 2707 N mm⁻² and MOR ≈ 22.6 N mm⁻², comparable to UF-bonded medium-density fiberboards (MDFs) for dry-use applications. Higher binder contents resulted in reduced strength and increased WA values. Thermogravimetric analysis (TGA/DTG) revealed an inorganic residue of 2.9–8.5% and slower burning compared to the UF-bonded panels. These results demonstrate that SCGs and ALS can be co-utilized as a renewable, formaldehyde-free adhesive system for manufacturing wood fiber composites, achieving adequate performance for value-added practical applications while advancing sustainable material development. Full article

Mortars taken from the 16th century Venetian Fortress of Bergamo (Italy) were characterized (binder-concentrated fractions and aggregate fractions as well as bulk samples) with a multi-analytical approach using X-ray diffraction (XRD), inductively coupled plasma optical emission spectrophotometry (ICP-OES), optical microscopy (OM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The results showed the presence of calcite, hydrocalumite and hydrotalcite-type compounds, brucite, aragonite, plombierite and a large fraction of amorphous phases (ranging between 14 and 27 wt%) in the binder. Quartz and carbonate-rich sands were used as aggregates. The mortar is a Mg-rich material containing 4–5 wt% brucite. No evidence of magnesite or hydromagnesite was found in any sample, although these phases are frequently detected in the binder of buildings from the Renaissance period that are located in Northern Italy. The large average amount (12–13 wt%) of reactive silicate, such as Mg-containing phyllosilicates that can react with lime, and the presence of carbonate-containing hydrocalumite and hydrotalcite indicate hydraulic interactions between lime and reactive silicate aggregates. The CO₂/H₂O_bound ratio, evaluated from the weight loss referred to the finer fraction (<63 μm), ranges from 1.99 to 2.55, which suggests that the walls of Bergamo were constructed using lime-based mortar with hydraulic properties. Full article

The high density of the internal structure of new-generation cementitious composites, such as high-performance and ultra-high-performance concretes, necessitates the use of advanced methods for evaluating their transport properties, particularly those employing a gaseous medium. The developed gas permeability method for cement pastes, based on a modified RILEM-Cembureau approach, has proven to be highly accurate, reliable, and extremely sensitive to changes in the porosity characteristics of such composites. The article contains the results of a study of the mass transport capabilities of blended cement pastes, characterised by variable water–cement ratios. Two types of cements were used in the study: with the addition of fly ash and blast furnace slag. Ordinary Portland cement was used as the reference binder. The tests were conducted after long-term curing under natural conditions, i.e., after 90 days and 2 years. The assessment of open porosity was carried out through three techniques: helium pycnometry, mercury intrusion porosimetry, and water saturation. Permeability, on the other hand, was measured using a customized approach tailored for uniform paste materials. Microstructural changes were also analysed in the context of natural hydration carbonation progress. The results presented allowed a quantitative description of the effects of the w/c ratio, the presence of additives, and the progress of hydration and carbonation on the porosity of pastes and their permeability to gas flow. The two-year curing period of the pastes exposed to natural CO₂ resulted in a reduction of the permeability coefficient k ranging from 11% to 74%, depending on the type of cement and the water-to-cement (w/c) ratio. This decrease was caused by the continued progress of hydration and simultaneous carbonation. The results of the research presented are of interest from both an engineering and scientific point of view in the context of long-term microstructural changes and the mass transport abilities of cement pastes associated with these processes. The extensive range of materials compositions investigated makes it possible to analyse the durability and tightness of many cementitious composites over long periods of service. Full article

Background and Clinical Significance: Binder syndrome or maxillonasal dysplasia is a rare developmental disorder affecting the anterior maxilla and nasal complex, characterized by midfacial hypoplasia, a flattened nasal bridge, and increased nasofrontal angle. Case Presentation: We present a case series of seven fetuses diagnosed with Binder phenotype through targeted ultrasound examination at our prenatal diagnosis center during the SARS-CoV-2 pandemic, between September 2021 and July 2023, including the first case described in the literature before 14 weeks. The median gestational age at diagnosis was 21 weeks. Ultrasound features included flattened fetal facial profile, increased nasofrontal angle (>143°), verticalized nasal bones and widened maxillary alveolar arch. Five cases presented as isolated anomalies, while two showed associated findings including growth restriction and polyhydramnios. Invasive prenatal diagnosis was offered in all cases, with three patients consenting to amniocentesis, all revealing normal karyotype and chromosomal microarray. Pregnancy outcomes varied: three patients opted for termination of pregnancy, one case resulted in intrauterine fetal demise, one delivered prematurely with confirmed postnatal phenotype, and two continued pregnancy with normal delivery. Conclusions: This relatively high case frequency within a short timeframe suggests that Binder syndrome, while rare, may not be as uncommon as previously reported. Accurate ultrasound diagnosis combined with comprehensive genetic counseling enables appropriate pregnancy management and optimal perinatal outcomes. Full article

A novel process for the synthesis of binder-free, porous nickel/polythiophene-functionalized sulfur (Ni/S-PTh) composite cathodes for lithium–sulfur (Li–S) batteries is introduced in this paper. Initially, a polyvinyl butyl polymer scaffold is 3D printed, then coated with a graphite-based conducting layer, and, finally, it is pulse-plated for nickel deposition to produce a high-surface-area, mechanically stable current collector. S-PTh particles are afterwards co-deposited into the Ni matrix through composite electrodeposition. After the dissolution of the polymer template, the resulting self-standing electrodes still maintain porous structure with uniform sulfur distribution and a distinct transition between the dense Ni layer and the Ni/S-PTh composite layer. Electrochemical characterization of the Ni/S-PTh composite cathodes by galvanostatic cycling at C/10 rate results in an initial specific discharge capacity of ~1120 mAh·g⁻¹ and a specific capacity of ~910 mAh·g⁻¹ after 200 cycles, resulting in a high capacity retention of ~81 %. For our novel approach, no steps at high temperatures or toxic solvents are involved and the need for polymer binders and conductive additives is avoided. These results demonstrate the potential of composite electrodeposition in combination with 3D printing for producing sustainable, high-performance sulfur cathodes with tunable architecture. Full article

HVAF WC-10Co-4Cr coating has been applied to the extreme wear protection of lightweight titanium alloy workpieces. However, the new generation of lightweight titanium alloy inner bore wear-resistant workpieces is faced with strong wear and instantaneous high-temperature airflow erosion during service, which requires a WC-10Co-4Cr wear-resistant coating with low surface roughness, high thickness and high toughness. In addition, its small diameter inner hole also requires the rapid heating, melting and acceleration performance of sprayed powder during spraying. At present, the finest spraying powder used in this system is generally in the range of 5–15 μm, which faces difficulties in meeting the above requirements. In order to solve this problem, the preparation of 2–10 μm spherical spray powder was studied though a spray granulation experiment, and the change law of powder morphology with the solid content of pre-spray slurry was explored. The suitable binder was selected through a slurry sedimentation test and viscosity test, so that the gunable solid content of the pre-sprayed slurry was reduced from 60 wt.% to 12.5% by weight, which significantly reduces the particle size of the powder obtained by spray granulation. When the solid content of pre-sprayed slurry is 12.5 wt.%, sodium carboxymethyl cellulose (CMC-Na) is selected as the binder, and the binder content is 2 wt.%, the particle size range of powder obtained by spray granulation process reaches 2–10 μm, and the median particle size reaches 5 μm. After heat treatment, the powder is spherical and dense inside. The research results provide technical support for preparing high-performance ultrafine WC-10Cr-4Co spherical powder with wear-resistant coating for light titanium alloy. Full article

Recycled coarse aggregates (RCA) offer an alternative to natural coarse aggregates in concrete production, reducing natural aggregate extraction and landfill burdens and potentially lowering embodied energy and CO₂ emissions. This study leverages machine learning algorithms to predict the dynamic yield stress (DYS) and plastic viscosity (PV) of RCA concrete (RCAC). A database of 380 RCAC mixtures, incorporating 11 input features, was analyzed using six machine learning models: Artificial Neural Network (ANN), Decision Tree (DT), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and Support Vector Machine (SVM). The model performance was compared, followed by sensitivity analyses to identify critical factors influencing DYS and PV. For DYS, the DT model demonstrated the highest predictive performance (testing R²/RMSE/MAE = 0.95/18.25/13.99; others: 0.90–0.93/12.14–26.10/15.40–19.50) due to its robustness on smaller datasets. The XGBoost model led for PV (testing R²/RMSE/MAE = 0.93/7.06/4.58; others: 0.82–0.89/8.69–11.20/6.06–7.51) owing to its sequential residual minimization that captures nonlinear interactions. Sensitivity analyses revealed that polycarboxylate superplasticizer content and water-to-binder ratio significantly influence DYS, while cement content and saturated-surface-dried water absorption of RCA (i.e., measured with open pores filled and the aggregate surface dry) dominate PV. The time-dependent role in affecting PV was also highlighted. By optimizing and comparing different machine learning algorithms, this study advances predictive methodologies for the rheological properties of RCAC, addressing the underexplored use of machine learning for RCAC rheology (DYS and PV) and the limitations of traditional empirical rheology methods, thereby promoting the efficient use of recycled materials in sustainable concrete design. Full article

The construction industry is a major contributor to global environmental impacts, particularly through the production and use of cement-based materials. In response to this challenge, this study provides a comprehensive synthesis of recent advances in the integration of Life-Cycle Assessment (LCA) and Artificial Neural Networks (ANNs) for optimizing cementitious composites containing Supplementary Cementitious Materials (SCMs). A total of 14 case studies specifically addressing this topic were identified, reviewed, and analyzed, spanning various binder compositions, ANN architectures, and LCA frameworks. The findings highlight how hybrid ANN–LCA systems can accurately predict mechanical performance while minimizing environmental burdens, supporting the formulation of low-carbon, high-performance cementitious composites. The diverse SCMs explored, including fly ash, slag, silica fume, waste glass powder, and rice husk ash, demonstrate significant potential for reducing CO₂ emissions, energy consumption, and raw material depletion. Furthermore, the systematic comparative matrix developed in this work offers a valuable reference for researchers and practitioners aiming to implement intelligent, eco-efficient mix designs. Overall, this study contributes to advancing digital sustainability tools and reinforces the viability of ANN–LCA integration as a scalable decision-support framework for green construction practices. Full article