Materials Science-Poland Feed

Carbon sequestration mechanisms and performance evolution of alkali-activated slag during the mixing process

Fri, 16 Oct 2026 00:00:00 GMT

This study investigated the direct incorporation of carbon dioxide (CO2) during the mixing of alkali-activated ground granulated blast furnace slag as an alternative to traditional post-hardening carbonation. CO2 was introduced during the final 30 s of mixing. The effects of alkali content and carbonation on CO2 uptake, compressive strength, water absorption, and microstructure were evaluated. The results showed that CO2 uptake increased with alkali content and exposure duration, with a maximum uptake of approximately 1.9% after 300 s of continuous CO2 exposure. The gravimetric and thermogravimetric measurements showed strong agreement, with an R 2 of 0.99. For the selected mortar mixtures, 30 s of CO2 exposure resulted in a 15–25% increase in 28-day compressive strength compared with non-carbonated specimens. However, water absorption showed a slight reduction. The microstructural analysis indicated carbonate-rich precipitates in pore and interparticle regions. The results demonstrate that introducing CO2 during alkali activation can promote in situ carbonate formation while improving the later-age mechanical performance of GGBFS-based alkali-activated materials.

Impact damage and energy-absorption mechanisms of basalt–steel hybrid fibre-reinforced low-carbon shotcrete for underground roadways

Wed, 30 Sep 2026 00:00:00 GMT

Underground roadway linings require sprayed materials that combine reduced embodied carbon, reliable delivery, early load resistance, and stable energy dissipation under rockburst-type impact. This study examined eight shotcrete mixtures: an ordinary Portland cement control, a fibre-free low-carbon matrix containing 30% ground granulated blast-furnace slag and 15% fly ash, two basalt fibre mixtures, two steel-fibre mixtures, and two basalt–steel hybrids. Static, dynamic, imaging, acoustic, mineralogical, and micromechanical measurements from three independent batches were integrated through mixed-effects models. The hybrid containing 0.10 vol.% basalt fibre (BF) and 1.00 vol.% steel fibre (SF) reached a 28-day compressive strength of 63.1 MPa, a flexural strength of 9.90 MPa, a fracture energy of 523 N/m, and a specific absorbed energy of 3.05 MJ/m3 at 80 s−1. Its cumulative drop-weight absorbed energy to through-cracking was 2.31 kJ, compared with 0.56 kJ for the fibre-free low-carbon mixture. Micro-computed tomography showed that hybridisation reduced crack volume from 4.20% to 1.35% and connectivity from 0.773 to 0.356. The mixture retained a 29.4% material-stage carbon reduction relative to ordinary shotcrete. The multitechnique observations were consistent with, but did not directly prove, a proposed sequence in which BFs restrain distributed microcracks and hooked SFs sustain widening macrocracks. LC denotes lowcarbon; LCH1 and LCH2 denote lowcarbon hybrid mixtures 1 and 2, respectively. LC-H1 is recommended where delivery tolerance governs, whereas LC-H2 is preferred for severe impact demand under the tested robotic spraying conditions, subject to full-scale field validation.

Effects of additive content on structure and properties of siderite tailings-based stone paper

Tue, 25 Aug 2026 00:00:00 GMT

This study utilized siderite tailings and polypropylene as the main raw materials to prepare stone paper composites through the melt blending and hot-pressing molding process. Using characterization techniques such as scanning electron microscopy and a universal electronic testing machine, the effects of the addition amounts of four different additives – calcium stearate, maleic anhydride grafted polypropylene, silane coupling agent KH550, and polypropylene toughening agent – on the microstructure, tightness, tensile strength, smoothness, and tear resistance of the materials were systematically investigated under a fixed tailings content of 40%. The results demonstrated that an appropriate number of additives effectively improved the overall performance of the materials, whereas excessive addition not only increased costs but also potentially led to a decline in performance. In summary, the rational use of additives significantly enhanced the compatibility and dispersion between the tailings and the polypropylene matrix. Under the specific conditions of 40 wt% siderite tailings loading and the processing parameters used in this study, the optimal addition amounts for calcium stearate, maleic anhydride grafted polypropylene, KH550, and the polypropylene toughening agent were found to be 2, 2, 2, and 5%, respectively.

Enhanced anticorrosion and antibacterial properties of epoxy coatings with silane coupling agent-modified graphene

Mon, 17 Aug 2026 00:00:00 GMT

Material corrosion represents a significant scientific and engineering challenge. Microorganisms on material surfaces accelerate corrosion. Due to the excellent properties of graphene, bifunctional anticorrosion and antibacterial coatings were developed by incorporating graphene into epoxy resin. To mitigate the detrimental effects of agglomeration on coating performance, graphene oxide (GO) was prepared, and a silane coupling agent was used to modify the surface of GO to enhance its stability and dispersibility within the coating matrix. The properties of graphene were analyzed before and after surface modification by Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM). Epoxy/modified-GO (0.1 wt%) coating revealed the highest corrosion resistance of 9.696 × 107 Ω cm2 after 144 h immersion in 3.5% NaCl solution measured by the electrochemical impedance spectroscopy (EIS) technique. Higher protection against bacteria was observed for epoxy/modified-GO (0.1 wt%) as the most efficient antibacterial composite coating. These results indicated that the coatings with modified graphene exhibited superior corrosion resistance and effectively inhibited the growth of Staphylococcus aureus.

Assessment of the applicability of laminates containing solid lubricants for sliding components

Mon, 10 Aug 2026 00:00:00 GMT

The aim of this study is to assess the applicability of UV-curable resin-based composite laminates containing solid lubricants as potential materials for sliding components. The tested laminates were produced from glass and carbon fiber fabrics impregnated with a photocurable resin modified with selected solid lubricants: molybdenum disulfide, polytetrafluoroethylene, and graphite. Tribological tests were carried out in a plate-roller configuration under technically dry friction conditions, using C45 steel as the counterelement. The analysis included the coefficient of kinetic friction, surface morphology after sliding, and maximum wear track depth. The results were compared with reference laminates without solid lubricant additives. The lowest coefficient of friction was obtained for the carbon-fiber-reinforced laminate containing molybdenum disulfide. For glass-fiber-reinforced laminates, graphite was the most effective additive in terms of friction reduction, decreasing the coefficient of friction by more than 17% compared with the reference sample. The results showed that the tribological effect of the same solid lubricant depends strongly on the reinforcement type. The investigated laminates therefore show potential for sliding applications; however, the selection of the lubricant additive should be adapted to the specific laminate system and operating conditions.

Optimization of humidification stabilization for SRF co-firing ash: Balancing expansion inhibition and drying shrinkage

Mon, 10 Aug 2026 00:00:00 GMT

Amidst the global transition toward carbon-neutral infrastructure, circulating fluidized bed boilers co-fired with solid recovered fuel represent critical nodes for circular resource recovery. However, the resulting residues exhibit volumetric instability due to unreacted free calcium oxide and anhydrous calcium sulfate, which compromises durability in cementitious composites. This study conducts a multi-scale investigation into the competitive volume dynamics – the trade-off between expansion mitigation and the induction of drying shrinkage. Using integrated characterization (X-ray diffraction, thermogravimetry, and scanning electron microscopy with energy-dispersive spectroscopy), we elucidate the micro-macro correlation in dimensional stability. Experimental results demonstrate that raw ash exhibits a destructive 7-day linear expansion of 1.62% (±0.12%) under accelerated testing in a 70°C water bath. Controlled humidification stabilizes the atypical ash by converting reactive precursors into stable calcium hydroxide and ettringite (Aft). Crucially, a suitable balance is identified: while 100% humidification eliminates expansion, it triggers a significant 1.21% (±0.08%) drying shrinkage. This is attributed to excessive Aft formation that refines pore structures, thereby elevating capillary tension governed by the Kelvin–Laplace effect. A 30% humidification protocol for 1 day strikes an optimal balance, controlling expansion to 0.39% (±0.04%) while mitigating shrinkage risk and ensuring the environmental sequestration of heavy metals (leachable lead < 0.12 mg/L). This research provides insights into the safe integration of atypical residues in sustainable binders.

Band gap engineering in Cu2FeSnS4 nanostructures via single (Ag) and co-substitution (Ag–Mn): Correlating structure, morphology, and optical properties

Fri, 10 Jul 2026 00:00:00 GMT

In this study, a quaternary Cu2FeSnS4 (CFTS) nano-compound was prepared and characterized using the solvothermal method, with partial substitution between copper and silver ions to form the Cu1.8Ag0.2FeSnS4 compound, in addition to a partial co-substitution between iron and manganese ions to form the Cu1.8Ag0.2Fe0.5Mn0.5SnS4 compound. The aim of the study is to compare single doping and co-doping and their effect on structural, optical, and morphological properties. The X-ray diffraction and Raman spectroscopy results showed that all the prepared compounds have a kesterite crystal structure with the absence of secondary phases, while maintaining the crystalline phase during the substitution process, accompanied by a slight change in the crystal lattice constants. Field emission scanning electron microscopy analysis revealed a clear evaluation in nanoparticle morphology with doping and co-doping. Brunauer–Emmett–Teller analysis indicated a decrease in surface area upon doping. It was also observed that there is a gradual decrease in the energy gap accompanied by strong absorption in the visible region when the doping and co-doping process is carried out. According to these results, the authors confirm that co-doping with silver and manganese is an effective strategy for controlling optoelectronic properties. It also has a clear impact on surface properties, which must be considered to balance maintaining an effective surface area with minimizing the energy gap. Therefore, these co-doped compounds are promising candidates for photocatalysis and thin-film solar cell applications.

Structural and biomedical evaluation of Capsicum annuum-assisted green synthesis of CuFe2O4 nanoparticles

Fri, 10 Jul 2026 00:00:00 GMT

An eco-friendly biosynthetic route was developed for the synthesis of spinel-structured copper ferrite nanoparticles (CuFe2O4 NPs) using Capsicum annuum (sweet green pepper) extract as a multifunctional reducing, capping, and stabilizing agent. This study systematically correlates the synthesis conditions with the structural, optical, magnetic, and biological properties of the synthesized material. X-ray diffraction analysis confirmed the formation of a cubic spinel structure with a nanocrystalline size of ≈26 nm, while Fourier transform infrared spectroscopy revealed the presence of metal–oxygen bonds and chemical reactions resulting from plant compounds. Optical analysis showed a low energy gap (≈1.5 eV), attributed to cation redistribution and the presence of defects in the crystal structure. Magnetic measurements also showed strong ferromagnetic behavior with a high coercivity value, attributed to the effects of single magnetic field. From a biological standpoint, the synthesized NPs showed improved antibacterial activity, along with low cytotoxicity against normal cells and excellent hematologic biocompatibility, with a hemolysis rate of <5%. These results demonstrate a clear correlation between the structural, physicochemical, and biological properties, highlighting the potential of green-synthesized CuFe2O4 NPs in advanced biomedical applications.

Process optimization research on surface remelting treatment of additive manufactured 316L stainless steel by circular oscillating laser

Fri, 10 Jul 2026 00:00:00 GMT

This study adopted circular oscillating laser remelting (COLR) to postprocess additive manufactured 316L stainless steel surfaces, systematically exploring its influence on surface roughness, subsurface defects, and material properties. Extended depth-of-field microscopy and scanning electron microscopy (SEM) were employed to characterize surface and cross-sectional morphologies, revealing surface-adhered spherical particles and subsurface defects (microcracks, pores, and ablation marks) predominantly distributed at 30–50 μm depth, with maximum crack depth reaching 99.98 μm and ablation particle depth of 46.77 μm. Response surface methodology was used to investigate the effects of key parameters (laser power, scanning speed, and rotation speed) on surface roughness and remelting depth. Results showed that at 120 W, insufficient energy–induced serrated undulations and molten pools of 40–50 μm with columnar grains; at 150 W, 23.41 μm-wide and 1.00 μm-high black micro-protrusions formed, accompanied by pools of 94–136 μm with columnar-equiaxed composite grains; at 180 W, violent pool fluctuations and edge spatters occurred, producing pools of 195–239 μm with 10 μm-thick columnar grains on the outer surface of the central region. Under the optimal parameters of 180 W, 5 mm/s, and 40 % rotation speed, COLR treatment reduced the surface roughness by ∼91% (from 7.3 to 0.65 μm) and increased the average microhardness of the remelted zone from approximately 222 HV (substrate) to 249 HV.

Lateral resolution enhancement in low-cost DLP 3D printing via integrated optical focusing and collimation

Wed, 03 Jun 2026 00:00:00 GMT

Digital light processing (DLP)-based additive manufacturing systems offer high printing speeds; however, their resolution is inherently limited in low-cost configurations due to projector pixel size, optical divergence, and angular light incidence on the photopolymer surface. In this study, a compact optical module consisting of focusing and collimation lenses was integrated between a commercial DLP projector and the photopolymer vat to address these limitations. The proposed system concentrates the projected light onto a reduced exposure area and enforces near-normal light incidence, improving voxel definition and suppressing angular curing artifacts. Benchmark geometries were fabricated with and without the optical module using a single daylight-sensitive photopolymer resin. The results show that the effective pixel size was reduced from approximately 165–170 μm to 43–46 μm. In addition, the increased irradiance enabled a reduction in layer exposure time from 2,500 to 100 ms, resulting in an overall printing time reduction of about 30%. Although the optical configuration limits the build area, it provides a purely physical and effective alternative to software-based super-resolution approaches for low-cost DLP systems.

Influence of binder-to-sand ratio on mechanical and durability properties of ultra-high-performance concrete reinforced with novel polyoxymethylene fiber

Fri, 08 May 2026 00:00:00 GMT

Ultra-high performance concrete (UHPC) faces cost and shrinkage challenges due to high binder contents. This study systematically investigates the influence of varying binder-to-sand (B/S) ratios (0.8, 0.9, 1.0, and 1.2) coupled with novel polyoxymethylene fibers (POMFs, 0 and 2% dosages) on UHPC properties. A fixed water-to-binder ratio (0.17) and 50% ground granulated blast-furnace slag replacement were used. Freshness, mechanical properties, durability, and microstructural properties were evaluated. Results indicate that the B/S ratio critically governs UHPC performance. Contrary to the assumption that higher binder content is always superior, an optimal balance emerged at a B/S ratio of 0.9. This ratio yielded the highest 28-day compressive and splitting tensile strengths, the lowest water absorption, and exceptional sulfate resistance, with no strength degradation after 180 days. A low B/S ratio (0.8) caused insufficient aggregate coating, increasing porosity, and reducing strength. Conversely, an excessive B/S ratio (1.2) induced severe autogenous shrinkage and microcracking, impairing durability and strength. While a 2% POMF addition provided limited gains in compressive strength, it significantly improved splitting tensile strength and shifted the failure mode from brittle to ductile. Scanning electron microscopy confirmed that POMF’s hydrophilic nature ensures excellent interfacial bonding with the matrix. Ultimately, a B/S ratio of 0.9 provides the optimal eco-efficient mix design, balancing high performance with material economy for UHPC engineering applications.

Integrative review of resin-based dental pit and fissure sealants: Composition analysis and a novel categorization proposal

Wed, 22 Apr 2026 00:00:00 GMT

IntroductionApplication of pit and fissure sealants is among the most effective methods of preventing dental caries. Despite their extensive use, the chemical composition of resin-based sealants is ambiguous and inconsistent. The presented integrative review analytically evaluates the composition of commercially available resin-based dental pit and fissure sealants.Data and sourcesTargeted searches were conducted between June 1 and November 15, 2025, using PubMed, ScienceDirect, Scopus, alongside general and academic search engines such as Google Scholar, Google. All relevant website entries were saved using the Internet Archive Wayback Machine platform.Study selectionSources providing information on key material components including resin matrix monomers and fillers; grey literature sources and scientific articles published in peer-reviewed journals regarding to the composition of resin-based commercial formulation of dental pit and fissure sealants. Structured data search resulted in identifying 52 formulations of 41 resin-based dental sealants. Among those, 116 unique ingredients were found, of which 41 were assigned a Chemical Abstracts Service number.ConclusionsComponents were classified according to their function into groups. Cluster analysis allowed for the proposal of a new classification of resin-based dental sealants based on their monomer composition. Three distinctive fluoride forms were identified in the analyzed formulations, with each one resulting in different release kinetics and therapeutic effect (fluoride salts, fluoride glass-ionomer fillers, and fluorinated monomers).Clinical significanceThe article highlights the significance and clinical importance of each group of identified compounds and aims to increase awareness of the correlation of composition with clinical properties.

Performance and microstructure of concrete containing green and LCD glass sand as fine aggregates

Tue, 21 Apr 2026 00:00:00 GMT

Rapid urbanization and environmental regulations have led to a shortage of natural river sand, prompting the use of alternative aggregates. This study evaluates green waste glass and liquid crystal display (LCD) glass sand as partial substitutes for manufactured sand (MS) in concrete. Comprehensive tests assessed mechanical properties (compressive and flexural strength), durability (drying shrinkage, impermeability, sulfate resistance), and alkali–silica reaction (ASR) potential. Microstructural evolution was analyzed using mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and electrical resistivity. Results demonstrate that a 20% green glass substitution (GG20) achieved optimal performance, with 28-day compressive and flexural strengths of 51.8 MPa and 6.1 MPa, respectively. Both glass types significantly reduced drying shrinkage and enhanced sulfate resistance by refining pores. Despite increased ASR activity in the LCD group, pozzolanic reactions and the micro-filling effect densified the paste matrix. This research validates specialized waste glass as a sustainable performance enhancer for manufactured sand concrete, offering a robust theoretical foundation for eco-friendly construction.

Regulation of microstructural evolution and tribological performance of extruded magnesium matrix composites reinforced with nano-WS2

Mon, 20 Apr 2026 00:00:00 GMT

Extruded magnesium matrix composites reinforced with nano-sized tungsten disulfide were fabricated via powder metallurgy followed by hot extrusion, and their microstructural evolution, mechanical response, and tribological behavior were systematically investigated. Compared with monolithic magnesium, the incorporation of 0.5–2.0 wt% nano-reinforcement markedly altered dynamic recrystallization behavior during extrusion, resulting in pronounced grain refinement and texture modification. Electron backscatter diffraction analysis revealed that the average grain size decreased from approximately 8.5 µm in pure magnesium to about 3.2 µm at 2.0 wt% addition, accompanied by a reduction in basal texture intensity from 12.5 to 7.8 m.r.d. These microstructural changes translated into substantial strengthening, with Vickers hardness increasing from 58 to 92 HV0.1, yield strength from 135 MPa to 220 MPa, and ultimate tensile strength from 210 to 315 MPa, while maintaining elongation above 10%. Tribological tests under dry sliding against GCr15 steel demonstrated a pronounced reduction in friction and wear. The steady-state coefficient of friction decreased from ∼0.45 for unreinforced magnesium to ∼0.18 at 20 N for the composite containing 2.0 wt% reinforcement, and the corresponding wear rate was reduced by nearly one order of magnitude, from ∼1.8 × 10⁻4 to ∼1.5 × 10⁻5 mm3 Nm. Surface and debris analyses confirmed the formation of a continuous lubricious tribolayer that mitigated severe adhesive and abrasive wear. The results collectively demonstrate a clear composition–structure–property relationship, highlighting the effectiveness of nanoscale layered reinforcements combined with extrusion processing for achieving a balanced improvement in strength and wear resistance in lightweight metallic composites.

Analytical and finite element analysis of stress concentration factors for polyvinylchloride reinforced with different types of short fibers

Tue, 17 Mar 2026 00:00:00 GMT

The objective of the current research is to study the effect of a central circular hole as a stress raiser and to obtain the corresponding stress concentration factors for polyvinyl chloride (PVC) reinforced with different types of short fibers. Five different types of fibers were used: glass wool (GW), rock wool (RW), cotton wool (CW), and glass fiber with two types (YGT101 and E6-CR). The fibers of 5, 10, 15, 20, 30, 40, and 50% were used for sample preparation. On the other hand, two different types of samples were used: unnotched samples and notched samples with central holes of 1, 3, and 5 mm in diameter. Tensile tests were carried out on dog bone samples according to ASTM D638 using a universal tensile testing machine. The experimental results showed that the tensile strength of the PVC/fiber composites decreases with the increase of wt% of the fibers, whereas the PVC/E6-CR fiber composites displayed different behaviors. On the other hand, the results obtained for stress concentration factors from finite element analysis models and analytical methods showed that there is no effect for the types of fibers, and additionally, the stress concentration factors obtained from the different models were approximately the same, with differences not more than 10% for the same hole diameter.

Advancing cementless composites by contrasting the thermomechanical performance and printability of additively manufactured and cast structures

Wed, 25 Feb 2026 00:00:00 GMT

This study developed and verified a novel, alkali-free cementless material for 3D printing, formulated entirely from industrial by-products: circulating fluidized bed co-fired fly ash (CFA), blast furnace slag, fly ash, and reactive ultra-fine fly ash (RUFA). The research aimed to eliminate cement and hazardous liquid alkali activators by using the self-activated properties of CFA to activate the slag. The experimental program evaluated rheological properties for printability, compared the compressive strength of cast and 3D-printed specimens to assess anisotropy, and analyzed thermal conductivity and interlayer bonding using optical microscopy. Results showed the optimized cementless mixtures achieved stable fluidity and good extrudability, though with longer setting times than traditional alkali-activated materials (AAMs). While AAMs had superior compressive strength (over 60 MPa), their rapid hardening created weak interlayer bonding. Conversely, the cementless composites maintained continuous fusion and achieved lower thermal conductivity (minimum, 0.233 W/m K) due to an interstitial pore structure from RUFA. The study concluded that while AAMs were better suited for high-strength applications, the developed alkali-free composite offered a sustainable and energy-efficient solution for non-structural elements, striking a balance between buildability and thermal insulation. Its innovation lay in creating a self-activating, all-waste binder system that avoided corrosive chemicals while enabling tunable thermal properties in additive manufacturing.

Structure, electrical, and giant dielectric properties of fine-grained Na1/2Bi1/2Cu3Ti4O12 ceramics synthesized by mechanochemical activation and low-temperature spark plasma sintering

Tue, 24 Feb 2026 00:00:00 GMT

Na0.5Bi0.5Cu₃Ti₄O₁₂ (NBCTO) ceramics were synthesized by mechanochemical milling followed by spark plasma sintering (SPS) at 800–900°C. X-ray diffraction confirmed the cubic perovskite structure, with minor CuO traces at lower sintering temperatures and phase-pure NBCTO at 900°C. Scanning electron microscope and energy-dispersive X-ray spectroscopy revealed dense, fine-grained microstructures with average grain sizes below 400 nm, significantly smaller than those observed in conventionally sintered samples. All SPS-NBCTO ceramics exhibited colossal dielectric permittivity (ε′ > 10⁴) across wide frequency and temperature ranges, with values of 2.8–4.0 × 10⁴ at 1 kHz and room temperature. Impedance analysis revealed an internal barrier layer capacitance mechanism, with semiconducting grains and more resistive grain boundaries. Grain conductivity (∼3 × 10⁻² S/cm) and activation energies (0.089–0.096 eV) were consistent with CaCu₃Ti₄O₁₂-based systems, while grain boundary conductivity was unexpectedly high (2.5–3.5 × 10⁻³ S/cm) with relatively low activation energies (0.192–0.211 eV). These properties, linked to oxygen-vacancy-related conduction, led to unusually large dielectric losses. Relaxation analysis using the electric modulus confirmed thermally activated grain and grain boundary processes with activation energies matching conductivity values. The results demonstrate that SPS enables fine-grained, dense NBCTO ceramics with colossal dielectric constants, though excessive grain boundary conduction remains a challenge.

Cyclic loading test for brick masonry walls strengthened by steel mesh-ECC layers

Sun, 18 Jan 2026 00:00:00 GMT

To evaluate the seismic performance of masonry walls strengthened with a steel mesh-sprayed Engineered cementitious composite (ECC) layer, low reversed cyclic loading tests were conducted on walls strengthened with steel mesh-ECC and steel mesh-mortar overlays and compared with an unstrengthened specimen. Considering the superior mechanical properties of ECC and the importance of the wall-overlay bond, a novel strengthening method is proposed in which a steel mesh is embedded in the ECC layer and anchored to the wall through tie bars to enhance interfacial bonding and ensure composite action under lateral loading. The study focused on the shear load-bearing capacity, ductility, energy dissipation capacity, and failure patterns of the walls. The results indicated that the failure pattern of the unstrengthened masonry wall was shear failure, accompanied by diagonal cracks. The masonry wall strengthened by steel mesh-ECC layer underwent bending failure. Compared with the unstrengthened specimen, the peak load, ductility coefficient, and yield load of specimen strengthened with steel mesh-mortar layer increased by 25.38%, 27.81%, and 22.22%, respectively, while the peak load, ductility coefficient, and total cumulative energy dissipation of specimen strengthened with steel mesh-ECC layer improved by 60.17%, 48.34%, and 566%, respectively. The hysteresis curve of the strengthened masonry walls was more stable, the stiffness degradation curve was smoother, and the equivalent viscous damping coefficient and cumulative energy dissipation increased at each displacement level. The masonry wall strengthened with steel mesh-ECC layer exhibits enhanced seismic performance. This research provides a technical reference for the steel mesh-ECC strengthening in masonry walls.

Flexural strength of low-strength RC beams using CFRP composite

Wed, 31 Dec 2025 00:00:00 GMT

Over the past few decades, utilizing fiber-reinforced polymer in strengthening or rehabilitation of structural members has become a highly promising technique to extend reinforced concrete (RC) structures' lifespan and enhance their structural integrity. Rehabilitation of old structures is necessary due to various factors, including harsh environments, earthquakes, increased loads, corrosion in reinforcement, and inadequate design. Numerous studies have examined the strengthening of RC beams in shear and flexure using carbon fiber reinforced polymer (CFRP) composites with different schemes, including bonding CFRP externally, through experimental and theoretical investigations. In this study, a series of eight RC beams was cast with low-strength concrete. The beams were designed to be weak in flexural. Flexural critical RC beams were strengthened with different CFRP application schemes. The experimental findings were validated through both numerical and analytical analyses, demonstrating close agreement. The results indicate that the application of CFRP laminate or fabric increased the ultimate load in flexural strengthening applications by approximately 40–60%, particularly when CFRP was bonded to the bottom soffit with CFRP U-jacketing placed at both ends. Furthermore, placing a 50 cm CFRP U-jacket at both ends of RC beams, critical in flexural and strengthened using a CFRP laminate at the soffit of the section, led to a 120% increase in load capacity with elastic behavior.

Quality assessment of heat-treated rails in the R350HT grade

Wed, 31 Dec 2025 00:00:00 GMT

This article presents the results of tests on heat-treated R350HT grade rails, which were manufactured on a railhead heat treatment line installed in the heavy section mill of the AMP Branch in Dabrowa Gornicza. The research article presents an analysis of the chemical composition of the tested rails and their basic mechanical properties. It also discusses in detail the fatigue testing procedure performed in accordance with the qualification tests specified for rails in the EN13674-1 standard and the DBS 918 254-1 technical specifications. Microstructure analysis, including pearlite morphology assessment, and macrostructure evaluation results are presented. Results of determining the stress intensity factor, fatigue crack growth rate, fatigue strength, and determination of vertical and horizontal fatigue strength using the staircase method for R350HT steel grade rails are also presented. The requirements for modern heat-treated rails are also discussed, and key rail property parameters that determine their operational properties are identified.