Search Results (392)

This study investigates the development and performance of polyolefin-based packaging materials reinforced with industrial mineral residues, specifically slate powder (SP) and bivalve shell powder (BSP). High-density polyethylene (HDPE) and polypropylene (PP) matrices were compounded with these fillers and processed by extrusion blow moulding to produce final prototypes. Thermal analyses (TGA and DSC) showed that incorporating SP and BSP does not compromise the thermal stability of the polymer matrices and increases stiffness in the filled formulations. Accelerated ageing (QUV, 200 h) revealed distinct photo-oxidative behaviours. PP and PP + BSP (30%) exhibited increased fragility and moderate colour changes, whereas PP + SP (10%) retained flexibility, indicating a partial protective effect of SP. HDPE-based formulations showed higher intrinsic UV resistance, with HDPE + BSP (30%) displaying excellent colour stability. Tensile tests before and after QUV exposure confirmed that fillers increase stiffness with limited influence on tensile strength. Air permeability results indicated that neat PP and HDPE were below the detection limit. At the same time, filled formulations exhibited measurable permeability, suggesting that filler incorporation may influence gas transport through interfacial effects. Overall, the results show that SP and BSP act as reinforcing additives and can modify functional properties such as stiffness and ageing resistance. However, their influence on barrier performance depends on the formulation and permeation mechanism. Full article

(1) Background: Cerium silicate (CeSi) nanoparticles (NPs) have potential as a restorative filler particle with multifunctional properties to improve longevity. To increase the biological activity, these nanoparticles can be fabricated with ultrasmall pores (mesoporous) (MPCeSi-NP) that can be loaded with a polyphosphate inhibitor, such as gallein. (2) Methods: MPCeSi-NPs were custom-synthesized with a microemulsion method, using cetyltrimethylammonium bromide (CTAB) as a template for self-assembly. Biocompatibility with oral keratinocytes/fibroblasts was tested, with the addition of examining the biomineralization potential with human bone-marrow-derived mesenchymal stromal cells (BM-MSCs). MPCeSi-NP, loaded with gallein, was tested against Rothia dentocariosa (Rd). MPCeSi-NP was added to a resin matrix of triethylene glycol dimethacrylate (TEGDMA) and Bisphenol A-glycidyl methacrylate (BisGMA) with subsequent mechanical properties evaluation. (3) Results: MPCeSi-NPs had high biocompatibility with oral keratinocytes and fibroblasts, especially at concentrations below 300 µg/mL. MPCeSi-NPs induced the biomineralization of BM-MSCs. Higher cerium levels increased mineralization. MPCeSi-NP had weak antimicrobial activity against Rd. At 1% wt, MPCeSi-NPs did not reduce the polymerization potential and mechanical properties of a TEGDMA:BisGMA polymer material, with controlled release of gallein in a simulated degradation model. (4) Conclusions: MPCeSi-NPs are highly biocompatible and bioinductive and have the potential to improve the biological response of current restorative materials. Full article

The article is devoted to the study of the properties of the obtained heat-insulating refractory materials, based on fireclay scrap of various fractions (2.5 mm, 1.0 mm, 0.5 mm, and 0.1 mm) using a complex of mineral and oxide additives. The fillers used were titanium dioxide powder and silicon production wastes, which included microsilica powder, aluminum oxide, zinc oxide, zirconium oxide, chromium oxide, iron oxide, cement, lime, and baking soda. The choice of these fillers was due to the fact that they initially have corrosion resistance. Liquid glass acted as a binder. The resulting thermal barrier material was tested to determine its physical and mechanical properties, namely, thermal conductivity, porosity, compressive strength, and microstructure. According to the obtained results for the physical and mechanical properties, the secondary refractory material had properties close to GOST. So, according to GOST 12170-2021, the thermal conductivity values of the obtained materials were included in the 0.03–15.0 W/(m·K) range. The porosity values of the obtained samples complied with GOST 2409-2014 and were not more than 30%. The maximum compressive strength was 171.31 kgf/mm². The microstructure of the material of the obtained samples was very porous, and the pores were evenly distributed throughout the volume, which is extremely important for heat-insulating materials. A distinctive feature of the technology was the absence of a high-temperature firing stage: the required physical and mechanical properties of the material were achieved when heated to 180–300 °C with subsequent slow cooling in the furnace, which significantly reduces energy consumption compared to traditional refractory technologies. The use of waste from the production of chamotte scrap and microsilica will help to reduce negative impacts on the environment, save natural resources, and expand the raw material base. Full article

The rapid development of tropical island tourism has put forward a higher demand for asphalt pavement construction on the island. However, the asphalt pavement engineering in the offshore area is generally faced with high material transportation costs. Additionally, challenges such as high-temperature climate and heavy-load traffic may lead to permanent pavement deformation. As a typical marine solid waste, shells have high calcium carbonate content and porous structures, which have the potential advantage of modified asphalt. In this study, mixed shell powder was used as a modified material, and 70 # base asphalt and SBS-modified asphalt were mixed, respectively. The effect of asphalt modification was analyzed by basic performance tests and high-temperature rheological tests. An asphalt mixture was prepared by replacing limestone powder with mixed shell powder in equal volume, and its road performance was systematically tested. The modification mechanism was revealed by means of a microscopic test. The results show that the recommended content of mixed shell powder in SBS-modified asphalt is 9%, and 50–100% mixed shell powder can be used to replace mineral filler in base asphalt and single SBS modified asphalt mixture. This study provides effective technical support for the utilization of shell solid waste in offshore areas and the optimization of asphalt pavement performance. Full article

The cement industry is a major contributor to global energy consumption and greenhouse gas emissions, motivating the development of sustainable cementitious materials through partial cement substitution. This study investigates the combined mechanical, durability-related, and environmental performance of mortars incorporating a 20% replacement of Portland cement by volume with different natural and waste-derived mineral additions, including natural pozzolan, brick waste, glass powder, recycled concrete powder, and calcined clay as pozzolanic or potentially reactive supplementary materials, while silica sand was used as an inert mineral filler. Mechanical performance was evaluated through compressive strength, while durability-related behavior was assessed using water absorption by immersion at 28 days. In parallel, a Life Cycle Assessment (LCA) was conducted to quantify the environmental impacts associated with climate change, acidification, eutrophication, photochemical oxidant formation, material resource depletion, and non-renewable energy consumption. The results show that mortars incorporating natural pozzolan and brick waste achieved compressive strengths comparable to the reference mortar, while maintaining low water absorption values, indicating effective microstructural densification. Glass powder also provided acceptable mechanical and durability-related performances, whereas silica sand, recycled concrete powder, and calcined clay exhibited reduced strength and increased absorption due to dilution effects, inherited porosity, or delayed pozzolanic activity. From an environmental perspective, all cement-substituted mortars demonstrated significant reductions across all assessed LCA impact categories, with decreases typically ranging from 15% to 20% relative to the reference mix. The most pronounced environmental benefits were observed for mortars incorporating waste-derived materials, particularly brick waste. Overall, the combined mechanical and environmental assessment demonstrates that a 20% cement substitution using supplementary materials can substantially reduce the environmental footprint of mortars without compromising essential engineering properties. Full article

This study investigates the development of mixed matrix membranes based on polyethersulfone incorporated with attapulgite for gas separation applications, addressing the existing gap regarding the use of this mineral in dense membranes obtained exclusively by solvent evaporation and its combined effects on microstructure and transport. The membranes were prepared by phase inversion via solvent evaporation, using solvent/polymer ratios of 75/25 and 80/20 and a thickness of 0.25 mm. The solutions were evaluated in terms of viscosity, and the membranes were characterized by structural techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), contact angle, mechanical properties (tensile testing), and water vapor permeation. The results showed that attapulgite incorporation promoted a reduction in surface roughness (up to ~40%) and a decrease in contact angle (from ~89° to ~68°), indicating increased hydrophilicity. In addition, water vapor permeability was influenced in a non-linear manner, with optimized performance observed at 3 wt% filler loading. Solution viscosities remained within ranges suitable for processing. Structural analyses indicated compatibility between the phases, while morphology changes dependent on filler content were decisive for transport behavior. It is concluded that attapulgite is a promising additive for fine-tuning membrane properties, enabling optimization of the sorption–diffusion balance and improvement of membrane performance in separation applications. Full article

Silicone pressure-sensitive adhesives are a prominent group of adhesive materials used in many contemporary industrial sectors. This is due to their high resistance to difficult operating conditions, especially high temperatures. They are used, among other areas, in the automotive industry or in power engineering, as fastening or insulation systems operating at high temperatures. Previous studies have demonstrated the beneficial effect of mineral fillers on further increases in thermal resistance and dimensional stability of silicone pressure-sensitive adhesives. This paper presents the results of research on the effect of adding rose quartz as a filler to silicone pressure-sensitive adhesives based on polydimethylsiloxanes, on the adhesion parameters of the obtained adhesives and their thermal resistance and dimensional stability at elevated temperatures. The self-adhesive tapes obtained showed increased resistance and thermal stability while maintaining the required performance parameters. Among the tested compositions, optimal PSA parameters were achieved for Q2-7358 resin filled with 0.5 pph of rose quartz particles: adhesion exceeded industrial requirements by more than 15%, and tack met those requirements. Furthermore, low (and consistent) shrinkage (0.4% after one week) and cohesion—evaluated as hold time > 72 h—were recorded. As the most important parameter for studied compositions, thermal resistance (SAFT) substantially increased (>225 h) in comparison to neat resin (150 h). Full article

The strength of cemented tailings backfill (CTB) is influenced by multiple factors, with the type of cementitious material playing a crucial role in determining the strength of the backfill. To investigate the influence of two different cementitious materials on the strength of CTB, based on the fundamental physicochemical properties of tailings, flow characteristic tests and uniaxial compressive strength (UCS) tests of the backfill were conducted using a cementitious backfill slurry prepared from tailings. Representative proportioned backfill specimens were selected for X-ray diffraction (XRD) and scanning electron microscope (SEM) microstructural analysis to study the evolution patterns of backfill strength influenced by cementitious material type, cement-to-tailing (c/t) ratio, and slurry concentration. The results indicate that the tailings exhibit favorable gradation but unstable continuity. Furthermore, a high content of clay minerals such as kaolinite, along with the presence of fluorine (F) and phosphorus (P), adversely affects the strength of fillers. In terms of slurry flowability, the fluidity of cementation powder filling slurry is generally superior to that of cemented filling slurry. In identical conditions, the strength of cementation powder fillers at all ages is significantly higher than that of cement. As the c/t ratio decreases, the strength advantage of cementation powder fillers becomes even more prominent. Compared to cemented fillers, the hydrated product calcium silicate hydrate gel (C-S-H gel) in cementation powder fillers is more abundant, while the hydrated product calcium aluminate hydrate (CAH) is coarser. This microscopic structural difference explains the strength characteristics of the fillers. Full article

Geopolymer concretes are increasingly regarded as advanced construction materials for applications requiring high thermal and chemical resistance. This article is a continuation of previously published research and focuses on the mechanical behaviour of geopolymer concretes containing aggregates made of foamed geopolymers and lightweight mineral aggregates, such as expanded clay and perlite, intended for use in chimney flue components. The aim of the study was to determine the influence of lightweight aggregates on the relationship between thermal insulation and the strength parameters of geopolymer concretes intended for use at elevated temperatures. Foamed geopolymer aggregates were produced by a controlled chemical foaming process, followed by grinding to specific grain sizes, yielding highly porous aggregates with low thermal conductivity, reaching approximately 0.075–0.099 W/(m·K). These aggregates were used as lightweight fillers in geopolymer concretes based on class F fly ash activated with alkaline solutions. The resulting composites were designed to combine low density and high thermal insulation with adequate mechanical strength. The mechanical properties of the developed concretes were assessed on the basis of compressive strength tests on cubic specimens and tensile strength in beam bending tests, carried out in accordance with standards. The results presented confirm that the use of foamed geopolymer aggregates enables a simultaneous increase in thermal insulation and the design of ultra-lightweight structural elements with sufficient load-bearing capacity for chimney systems (including suspended ones). This combination of low thermal conductivity, reduced mass, and appropriate mechanical properties makes geopolymer concretes with lightweight mineral and geopolymer aggregates a promising alternative to traditional ceramic materials. Full article

Rapid urbanization has intensified challenges regarding urban waterlogging and vehicle exhaust pollution. While permeable asphalt mixtures mitigate waterlogging and nano-TiO₂ offers photocatalytic exhaust degradation capabilities, the direct application of nano-TiO₂ is hindered by agglomeration and low photocatalytic efficiency. This study developed a composite modified nano-TiO₂ via metal ion doping and support treatment to enhance its performance in asphalt pavements. Specifically, nano-TiO₂ was doped with Fe³⁺, Ag⁺, and La³⁺ via the sol–gel method, and supported on activated carbon (AC) or Al₂O₃. The exhaust degradation performance was evaluated using a custom-built system, while dispersion properties were assessed via fluorescence microscopy and UV-Vis spectrophotometry. Furthermore, X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy were conducted to investigate the microstructural mechanisms underlying the doping modification and support treatment. Photocatalytic permeable asphalt mixtures were prepared by partially replacing mineral powder with the composite modified nano-TiO₂ to validate exhaust degradation and pavement performance. The results indicated that metal doping substituted Ti⁴⁺ in the lattice, inducing defects and reducing crystallite size to boost photocatalytic activity. The optimal doping concentrations are determined to be 1.0% for Fe³⁺, 1.5% for Ag⁺, and 1.0% for La³⁺. Among these, Fe³⁺-doped nano-TiO₂ at 1.0% content exhibits superior exhaust degradation, achieving 46.7% efficiency for hydrocarbons (HC) and 33.5% for nitrogen oxides (NO). Regarding dispersion, while AC performs better at low support content, Al₂O₃ at 40% content provides superior dispersion properties by increasing active sites and surface hydroxyl groups. For photocatalytic permeable asphalt mixtures, replacing 40–50% of mineral filler with the composite modifier is recommended. The optimized mixture demonstrates superior exhaust degradation performance while maintaining the required high-temperature stability, low-temperature cracking resistance, water stability, and fatigue life. Specifically, compared to the control group, these indicators for the mixture with 50% of the mineral filler replaced by the composite modifier increases by 7.0%, 12.5%, 13.4%, and 22.9%, respectively. This study presents a viable technical solution for developing multifunctional asphalt mixtures with photocatalytic functionality as the core innovation and mechanical performance as the application baseline. Full article

Artificial composite stones have recently attracted attention as multifunctional materials for construction and defense-related applications. In this study, a novel composite stone was developed using waste limestone as the primary mineral filler, combined with an unsaturated polyester resin matrix and reinforced with glass powder and chopped glass fibers. The influence of binder content and reinforcement type on physico-mechanical and microstructural behavior was investigated. Experimental characterization included water absorption, compressive strength, abrasion resistance, acid resistance, and optical microscopy. The results demonstrated that fine fillers improved matrix densification and reduced porosity, while short glass fiber reinforcement enhanced load-bearing capacity. Abrasion resistance and durability were found to depend on binder content and particle packing characteristics. Overall, the developed composite material exhibits promising mechanical performance, low water absorption, and improved durability, suggesting its potential as a candidate material for applications requiring environmental resistance, including potential use in defense-related camouflage applications. Full article

Brazilian soils are prone to a gradual decline in fertility due to intensive agricultural activity combined with natural weathering, which increases the demand for chemical fertilizers. Among potential alternatives, soil remineralization using crushed rock is a promising strategy. Silicate agrominerals (SAs) applied as soil remineralizers have attracted attention due to their ability to supply plant-available nutrients while reducing dependence on conventional mineral fertilizers. This study evaluated the potential of residues from six quarries in Brazil as soil remineralizers as a regulatory screening assessment. Samples were subjected to mineralogical, petrological, and chemical characterization using an integrated approach, including X-ray diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and leaching experiments. XRD analysis revealed that anorthite and augite were the major minerals present in the mining waste. These minerals are less resistant to weathering, which enhances the release of macro- and micronutrients, essential for the development of various crops. Chemically, the samples were dominated by SiO₂, Fe₂O₃, and Al₂O₃, with the sum of bases (K₂O + CaO + MgO) ranging from 11.92% to 16.85%, meeting Brazilian standards for use as a soil remineralizer. Leaching results revealed that pH responses varied significantly among the studied samples for the filler particles, with an alkaline shift reaching values above 9.0 after 72 h. In contrast, the powder particle size samples showed no significant variation between the different materials tested, maintaining nearly constant pH levels throughout the period. This preliminary evaluation demonstrates that mining tailings from Brazilian quarries have potential as a sustainable soil remineralizer. This approach not only offers an alternative for soil fertilization but also promotes waste management and circular economy practices, although further studies are needed to assess long-term effectiveness and safety. Full article

The development of all-concrete liquefied natural gas (LNG) storage tanks is hindered by the susceptibility of conventional concrete to ultra-low temperature (ULT) cycling down to −70 °C. While redispersible polymer powder (RPP) and polypropylene (PP) fibers individually enhance performance, their combined effect in various mineral admixture systems remains unclear. This study investigates the synergy and selective compatibility in hybrid-modified concrete containing fly ash (FA), silica fume (SF), or slag (SG). Comprehensive assessments after 50 ULT cycles reveal that the efficacy of hybrid modification is intrinsically governed by the mineral admixture. Among all systems, the silica fume-based hybrid system (EPSF) exhibits the highest residual compressive strength (57.5 MPa), the lowest strength loss (6.7%), and the most balanced durability. Microstructural analysis reveals that this synergy arises from a dense matrix, continuous polymer network, and effective fiber bridging—achieved only when the mineral admixture enables uniform RPP distribution. In contrast, the FA system exhibits a strength–durability trade-off, with RPP localized at interfaces, while the SG system shows a polymer-activated hydration mechanism. Microstructural and nano-mechanical analyses confirm that RPP acts as a pore filler in cement, an interfacial modifier in FA, a cohesive network former in SF, and a hydration activator in SG. This work establishes that superior ULT resilience requires not merely additive modifications but a matrix-enabled synergy, providing a scientific basis for the rational design of cryogenic concrete. Full article

Biomimetics in dental restorative materials has gradually shifted from simply copying the appearance of natural teeth to better understanding how those tissues actually behave. Instead of focusing only on aesthetics, there is now more attention on how enamel and dentin function in real conditions, how they respond to stress, interact with their surroundings, and change over time. Because of this, newer materials are no longer just passive fillers; they are being designed to reflect aspects of natural tooth structure, composition, and behavior within the oral environment. This review brings together key ideas in this area, recent developments, and the challenges that remain. One issue that often comes up is how terms like bioinspired, biomimetic, and bioactive are used. They are sometimes treated as if they mean the same thing, but in practice, they point to different goals or levels of complexity in material design. For instance, some studies focus on creating more organized composite structures or mimicking natural mineralization processes, while others focus on antibacterial surfaces or peptide-based approaches that may support remineralization. There is also growing interest in materials that respond to environmental changes, such as shifts in pH or the early stages of wear. Even with promising laboratory results, these materials are not yet widely used in everyday clinical practice. Several issues continue to slow their adoption, including unclear terminology, limited availability of testing models that reflect real oral conditions, and a lack of long-term clinical data. Part of the challenge lies in the lack of consistent terminology, which can make it harder to compare findings across studies. Manufacturing challenges also remain, particularly when scaling up more complex systems. Moving forward, progress will depend on closer collaboration across disciplines, including materials science, oral biology, microbiology, and digital manufacturing. Such efforts will be important for developing restorative materials that behave more like natural tissues and perform reliably over time inside the mouth. Full article

This study provides new experimental evidence indicating that powdered mineral wool waste traditionally classified as a non-reactive, non-recyclable insulation residue can function as a genuinely pozzolanic supplementary cementitious material when incorporated into Portland cement systems. Unlike previous work that has treated mineral wool exclusively as an inert filler, this research demonstrates that its amorphous silicate–aluminate phase becomes chemically active under high-alkalinity conditions. A combined experimental programme, including mechanical testing, assessment and SEM/EDS microstructural analysis, was used to evaluate replacement levels of 20%, 25%, and 40% in CEM I mortars, with CSA cement employed as a contrasting binder system. The results indicate a potential contribution of powdered mineral wool to strength development; however, this effect cannot be unequivocally attributed to pozzolanic activity alone. It may also be partially related to physical effects such as filler action and particle packing. SEM/EDS observations confirm the formation of secondary C–S–H and C–A–S–H gels, can function as a genuinely pozzolanic supplementary cementitious material. Therefore, the applied assessment approach should be treated as indicative, and further verification using complementary methods is required. This study provides new experimental evidence indicating mineral wool can potentially contribute to cementitious performance as a Supplementary Cementitious Material (SCM). However, these observations should be treated as qualitative and indicative rather than definitive proof of pozzolanic reaction. The study provides an environmentally relevant valorisation pathway for a problematic waste stream, showing that mineral wool residues containing only trace levels of immobilizable formaldehyde can be safely and effectively integrated into low-carbon binder technologies. These findings position powdered mineral wool as a previously overlooked, yet technically viable SCM, offering new opportunities for clinker reduction, waste circularity and sustainable cementitious material design. Full article