Search Results (1,086)

Pavement texture is a crucial factor influencing both skid resistance and durability. This study aims to investigate the impact of texture reconstruction on pavement performance, which holds significant scientific value for enhancing road safety and durability. The research focuses on the reconstruction of airport cement pavement textures through the design of seven solid–liquid, two-component coating formulations, comprising three types of coatings: emulsion coating (P), waterborne epoxy coating (E), and water-based coating (W). Laser texture scanning technology was employed to identify the texture characteristics, which, combined with the British pendulum test, enabled a comprehensive analysis of skid resistance. Additionally, the coating–concrete interfacial strength and frost resistance were evaluated through pull-out tests, flexural strength tests, and freeze–thaw cycle tests. The results demonstrated that, compared to uncoated concrete, the mean profile depth (MPD) of the P, E, and W coatings increased by 43.4%, 34.7%, and 21.6%, respectively. Furthermore, the peak band of the slope spectrum density (SSD) shifted from a range greater than 1 mm to approximately 0.5 mm following coating application. The British pendulum number (BPN) increased by 25%, 20%, and 15% for the P, E and W coatings, demonstrating a strong correlation with MPD (R² = 0.95). These results indicate that the coated surface texture exhibits superior properties, which explain the enhanced slip resistance from a textural perspective. Moreover, the interfacial strength between the coating and concrete initially increased and then decreased with increasing coating thickness. In comparison, the interfacial bonding strength of the E coating was significantly higher than that of the P and W coatings. Furthermore, compared to the P and W coatings, the flexural bond strength of the E coating increased by 7% and 74%, respectively. After undergoing the freeze–thaw cycle, the E coating exhibited the best freeze resistance, while the W coating exhibited the poorest performance. In summary, the P coating excelled in texture reconstruction, while the E coating provided superior bonding and freeze resistance. This paper presents a novel approach to the development of coating materials for use on airport pavements. Full article

Bronze materials are indispensable across numerous industries for enhancing the durability and performance of components, primarily due to their excellent tribological properties, corrosion resistance, and machinability. This study investigates the impact of different atmospheric conditions on the properties of WAAM (wire arc additive manufacturing) cladded bronze coatings on 09G2S steel substrate. Specifically, the research examines how varying atmospheres—including ambient air (N₂/O₂, no shielding gas), pure argon (Ar), carbon dioxide (CO₂), and 82% Ar + 18% CO₂ (Ar/CO₂) mixture—influence coating defectiveness (porosity, cracks, non-uniformity), wettability (manifested as uniform layer formation and strong adhesion), and the extent of intergranular penetration (IGP), leading to the formation of characteristic infiltrated cracks or “bronze whiskers”. Modern investigative techniques such as optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were employed for comprehensive material characterization. Microhardness testing was also carried out to evaluate and confirm the homogeneity of the coating structure. The findings revealed that the bronze coatings primarily consisted of a dominant, highly textured FCC α-Cu phase and a minor BCC α-Fe phase, with Rietveld refinement quantifying a α-Fe volume fraction of ~5%, lattice parameters of a = 0.3616 nm for α-Cu and a = 0.2869 nm for α-Fe, and a modest microstrain of 0.001. The bronze coating deposited under a pure Ar atmosphere exhibited superior performance, characterized by excellent wettability, a uniform, near-defect-free structure with minimal porosity and cracks, and significantly suppressed formation of bronze whiskers, both in quantity and size. Conversely, the coating deposited without a protective atmosphere demonstrated the highest degree of defectiveness, including agglomerated pores and cracks, leading to an uneven interface and extensive whisker growth of varied morphologies. Microhardness tests confirmed that while the Ar-atmosphere coating displayed the lowest hardness (~130 HV_0.1), it maintained consistent values across the entire analyzed area, indicating structural homogeneity. These results underscore the critical role of atmosphere selection in WAAM processing for achieving high-quality bronze coatings with enhanced interfacial integrity and functional performance. Full article

Ultra-high-performance concrete (UHPC) has been widely utilised in strengthening and rehabilitating conventional normal concrete (NC) structures due to its exceptional mechanical properties and durability. However, in cold climates, the interfacial bond between UHPC and NC is susceptible to degradation under freeze–thaw cycles, potentially compromising the composite action and long-term performance of strengthened structures. This study systematically investigated the shear behaviour of a UHPC-NC interface with planted reinforcement subjected to various freeze–thaw conditions. The experiments were conducted considering different numbers of freeze–thaw cycles (0, 20, 40, 60, 80, and 100) and salt solution concentrations (0%, 3.5%, and 5%). Direct shear tests were performed to evaluate interfacial failure modes, mass loss, and shear strength degradation. Results identified three characteristic failure modes: adhesive debonding at the interface, mixed failure involving both the interface and the NC substrate, and crushing failure within the NC substrate. Specimens exposed to 3.5% salt solution experienced the most significant deterioration, exhibiting a 35% reduction in shear strength after 100 freeze–thaw cycles. Normally, lower salt concentrations were found to induce greater interfacial damage compared to higher concentrations. The study underscores the importance of increasing the embedment depth of the planted reinforcement to alleviate stress concentration and enhance interfacial durability in freeze–thaw environments. Full article

Work investigates the doping of molybdenum oxide (MoO_x) with tungsten (W). The successful incorporation of W into the MoO_x lattice was confirmed through X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS). Structural and optical analysis revealed the presence of oxygen vacancies within the W-MoO_x film, which are known to facilitate resistive switching (RS) in memristive devices. Based on this, a flexible memristor with the structure PET/ITO/W-MoO_x/polymethyl methacrylate (PMMA)/Al was fabricated. PMMA was strategically introduced between the W-MoO_x layer and the aluminum electrode to modulate interfacial properties that influence RS behavior. The W-MoO_x/PMMA-based memristor exhibited good resistive switching characteristics, with a memory window of approximately 12 and a retention time exceeding 2 × 10⁴ s, demonstrating a non-volatile memory behavior. In the high-resistance state (HRS), the conduction mechanism under higher applied voltages follows a space-charge-limited current (SCLC) model, indicating that the RS process is primarily governed by charge trapping and de-trapping at the interface. Overall, the consistent and robust switching performance of the W-MoO_x/PMMA heterostructure underlines its potential as a reliable functional layer for next-generation resistive random-access memory (ReRAM) devices. Full article

Metal anodes promise improvements in energy density and cost; however, their performance is determined within the first several nanometers at the interface. This review reports on how polymer-based artificial solid electrolyte interphases (SEIs) are engineered to stabilize Li and aqueous-Zn anodes, and how these designs are now evaluated against operando readouts rather than post-mortem snapshots. We group the related molecular strategies into three classes: (i) side-chain/ionomer chemistry (salt-philic, fluorinated, zwitterionic) to increase cation selectivity and manage local solvation; (ii) dynamic or covalently cross-linked networks to absorb microcracks and maintain coverage during plating/stripping; and (iii) polymer–ceramic hybrids that balance modulus, wetting, and ionic transport characteristics. We then benchmark these choices against metal-specific constraints—high reductive potential and inactive Li accumulation for Li, and pH, water activity, corrosion, and hydrogen evolution reaction (HER) for Zn—showing why a universal preparation method is unlikely. A central element is a system of design parameters and operando metrics that links material parameters to readouts collected under bias, including the nucleation overpotential (η_nuc), interfacial impedance (charge transfer resistance (R_ct)/SEI resistance (R_SEI)), morphology/roughness statistics from liquid-cell or cryogenic electron microscopy (Cryo-EM), stack swelling, and (for Li) inactive-Li inventory. By contrast, planar plating/stripping and HER suppression are primary success metrics for Zn. Finally, we outline parameters affecting these systems, including the use of lean electrolytes, the N/P ratio, high areal capacity/current density, and pouch-cell pressure uniformity, and discuss closed-loop workflows that couple molecular design with multimodal operando diagnostics. In this view, polymer artificial SEIs evolve from curated “recipes” into predictive, transferable interfaces, paving a path from coin-cell to prototype-level Li- and Zn-metal batteries. Full article

To elucidate the influence of the extrusion-based 3D printing of concrete on the tensile performance of polyethylene fibre-based engineered cementitious composites (PE-ECC), quantitative analyses of reinforcing filament alignment and pore morphology were carried out using backscattered electron (BSE) imaging and X-ray computed tomography (X-CT). A micromechanics analytical model based on microstructural characteristics was further employed to predict the tensile response of additively manufactured PE-ECC. Due to the extrusion process, fibres in 3D-printed PE-ECC were predominantly oriented along the printing path, resulting in a smaller average inclination angle compared with the randomly distributed fibres in cast specimens. Internal pores exhibited elongated flattened ellipsoidal shapes, with more pronounced anisotropy in axial lengths across the three principal directions. Taking the major semi-axis of the equivalent ellipsoidal voids as a representative pore parameter, the analytical model accurately reproduced the cracking strength, stress-strain evolution, and crack pattern of the printed PE-ECC. This extrusion process enhanced multiple cracking capacity and strain-hardening performance by improving fibre orientation, strengthening interfacial bonding, and altering matrix fracture toughness. The integration of micromechanical modelling with experimentally measured microstructural parameters effectively revealed the intrinsic mechanisms underlying the enhanced tensile behaviour of 3D-printed PE-ECC and provides theoretical support for the optimized design of fibre-reinforced cementitious composites in 3D printing. Full article

This study examines the influence of pyrolysis temperature on the physicochemical characteristics of malt-derived biochar (BC) and its effect on the performance of cement mortars. Malt biomass, a by-product of the brewing industry, was subjected to pyrolysis at 300 °C and 500 °C, followed by high-energy ball milling to produce nanoscale biochar. Characterization using FTIR, Raman spectroscopy, XRD, BET, SEM, and XRF revealed that BC500 possessed higher graphitic ordering, larger specific surface area (110 m₂/g), and smaller pore size compared to BC300, which exhibited greater hydrophobicity. Incorporation of BC500 into cement mortars at 0.25–1.0 wt.%, with and without superplasticizer, resulted in up to a 20.6% increase in compressive strength and a significant reduction in water absorption. These enhancements are attributed to the internal curing effect of biochar, its refined pore structure, and improved interfacial bonding with hydration products. The findings demonstrate that optimized malt biochar serves as a sustainable additive that improves the mechanical performance and durability of cementitious materials while advancing circular economy principles through the valorization of industrial malt waste and the mitigation of the environmental impact of cement production. Full article

Tin bronze/steel bimetallic is a widely utilized industrial material in the field of sliding bearing applications. Arc cladding technology represents an emerging method for fabricating tin bronze/steel bimetallic materials; however, research on their microstructure and mechanical properties remains limited. This study investigates the microstructural characteristics and mechanical behavior of tin bronze/steel bimetallic materials produced via the arc cladding process, with particular emphasis on the effects of annealing treatment on these properties. The tin bronze layer consists of a fine-grained zone, a columnar dendritic zone, and a freely dendritic zone. The tin bronze/steel bimetallic material exhibits high mechanical strength and strong interfacial bonding. Nevertheless, during three-point bending tests, cracks are observed in the tin bronze layer. When annealed at temperatures ranging from 300 °C to 700 °C, the tensile strength, shear strength, and hardness of the material decrease, while the elongation increases significantly. Moreover, no cracking occurs during three-point bending tests. Upon reaching an annealing temperature of 800 °C, the overall mechanical performance deteriorates rapidly. An annealing temperature of 300 °C is identified as an optimal parameter for achieving favorable mechanical properties. Full article

The evaluation of interfacial bonds between polymeric cementitious composites (PCCs) and concrete is considered as a critical factor to determine structural safety, durability, and service life regarding the repair and strengthening of old concrete structures. Conventional evaluations of interfacial bond strength have primarily relied on destructive testing methods, such as the pull-off and slant shear tests. However, these methods inherently possess fundamental limitations, including localized damage, non-uniform stress distribution, and uncertainty in result interpretation. This review aims to provide a comprehensive overview of existing standards and methods for assessing interfacial bond strength. For this purpose, the evaluation methods and results for the interfacial bond strength between cementitious composites such as PCCs and concrete were systematically reviewed. It further examines the characteristics and sources of error of the representative destructive method (pull-off test), highlighting its inherent limitations. Furthermore, this study conducted an in-depth analysis of a hybrid evaluation strategy combining non-destructive testing (NDT) and artificial intelligence (AI) to overcome the limitations of conventional interfacial bond strength assessment methods and minimize prediction errors. The results demonstrated that the NDT–AI hybrid approach, based on an ANN–BFGS model, achieved the highest accuracy in bond strength prediction and was identified as the optimal method for quantitatively and non-destructively evaluating interfacial bond behavior. Full article

Spinodoid nanocubes, inspired by spinodal decomposition, feature bicontinuous dual-phase architectures with high interfacial area, offering a promising platform for tuning nanoscale mechanics. In the present study, classical molecular dynamics simulations are carried out to investigate the mechanical properties and deformation behaviors of Au/Cu dual-phase spinodoid nanocubes. It is revealed that the ligament size of the spinodoid structure strongly influences material strength. As ligament size decreases, the strength of nanocubes increases until reaching a critical threshold, beyond which further refinement induces softening. This transition is governed by the semi-coherent interfaces through two competing mechanisms: for ligament sizes above the critical threshold, interfaces primarily impede dislocation motion, thereby strengthening the material; for smaller ligaments, interfacial plasticity, such as atomic rearrangements within the interface, provides a dominant softening mechanism. These findings highlight the critical role of characteristic length scale in determining the strength of nanocubes, and offer guidance for tailoring the mechanical performance of nanoscale dual-phase materials through structural design. Full article

Cementitious materials are multiscale and multiphase composites whose frost resistance at the macroscale is closely governed by microstructural characteristics. However, the interfacial transition zone (ITZ) between clinker and hydrates, recognized as the weakest solid phase, plays a decisive role in the initiation and propagation of microcracks under freezing conditions. Understanding the frost damage mechanism of ITZ is therefore essential for improving the durability of concrete in cold regions. The motivation of this study lies in revealing how freezing affects the mechanical integrity and microstructure of ITZ in its early ages, which remains insufficiently understood in existing research. To address this, a nanoscratch technique was employed for its ability to quantify local fracture properties and interfacial adhesion at the submicronscale, providing a direct and high-resolution assessment of ITZ behavior under freeze–thaw action. The ITZ thickness and fracture properties were characterized in unfrozen cement paste and in cement paste frozen at 1 and 7 days of age to elucidate the microscale frost damage mechanism. Moreover, the enhancement effect of nano-silica modification on frozen ITZ was investigated through the combined use of nanoscratch and mercury intrusion porosimetry (MIP). The correlations among clinker particle size, ITZ thickness, and ITZ fracture properties were further established using nanoscratch coupled with scanning electron microscopy (SEM). This study provides a novel micromechanical insight into the frost deterioration of ITZ and demonstrates the innovative application of nanoscratch technology in characterizing freeze-induced damage in cementitious materials, offering theoretical guidance for designing durable concrete for cold environments. Full article

In the field of water treatment, the development of efficient and environmentally friendly antibacterial materials to combat pathogenic contamination is of great significance. This work aimed to synthesize copper nanoparticles (CuNPs) using Rosa roxburghii extract (RRT) and Trichoderma harzianum mycelia-free cell filtrate (MFCF) as reducing agents. It was found that RRT-CuNPs had higher antibacterial ability than MFCF-CuNPs. Therefore, RRT-CuNPs were selected for further study. Through a functionalization modification strategy, polyvinyl alcohol (PVA) and chitosan (CTS) served as carrier matrices, with RRT-CuNPs as the highly efficient antibacterial active component and montmorillonite (MMT) as a reinforcing filler. The CTS/PVA/MMT/RRT-CuNPs composite gel beads were successfully fabricated via a cross-linking and blending method. For RRT-CuNPs-based gel beads, Fourier transform infrared spectroscopy (FTIR) displays that the composite hydrogel particles contain characteristic peaks of PVA, CTS, and MMT. By comparison, it is confirmed that MMT acts as both a reinforcing agent and a molecular structure regulator through interfacial interactions. X-ray diffraction (XRD) shows that MMT and CuNPs are dispersed in the particles. The study illustrates that the optimal initial concentrations of MMT, CTS, and CuNPs added to RRT-CuNPs-based composite gel beads were 4, 30, and 0.5 g/L, respectively. The prepared composite gel beads exhibited significant inhibitory activity towards Gram–positive bacteria (S. aureus) and Gram–negative bacteria (P. aeruginosa and E. coli), acquiring inhibition zone diameters of nearly 21 mm. As the dose of gel beads was 0.3 g/L and the action time was four h, the inhibition rate reached 100% through the plate counting method analysis. In conclusion, RRT-CuNPs-based composite gel beads have excellent antimicrobial activity, showing high potential application in the fields of water treatment. Full article

In situ graphene was grown on the surface of copper particles using highland barley powder, which is rich in sucrose and β-glucan, as a carbon source. The graphene content in the graphene-coated copper (Gr@Cu) composite powder was 4.98 wt.%. A characteristic angle of approximately 14° was observed between the graphene and copper crystal planes, indicating strong interfacial bonding. Raman spectroscopy revealed an ID/IG ratio of 0.96 for the graphene. Owing to the in situ growth of graphene, the mechanical properties of the copper matrix are effectively strengthened. At a graphene content of 0.7 wt.%, the graphene was uniformly dispersed within the copper matrix, resulting in optimized mechanical properties of the composite. This composite exhibited a conductivity of 70% IACS and a compressive yield strength of 175 MPa. Full article

A 2014Al matrix composite reinforced with 0.8 wt.% graphene nanoplatelets (GNPs) was prepared by pre-dispersion and ultrasonic melt casting. Subsequently, the as-cast 2014Al-GNP composite was subjected to hot extrusion under different parameters, followed by a comparative analysis of the microstructure and properties of the various alloys. Microstructure and phase composition of the prepared samples were characterized using OM, SEM, EDS, EBSD and TEM inspections. The results indicate that the addition of GNPs effectively promoted the refinement of the as-cast matrix alloy microstructure, while hot extrusion with appropriate parameters further refined the microstructure of the as-cast matrix alloy. At an extrusion ratio of 16, the Al₂Cu, Al₂CuMg, and GNPs in the microstructure displayed a band-like distribution along the extrusion direction, with reduced size and enhanced uniformity. Concurrently, the dislocation density and Kernel Average Misorientation (KAM) values of the composite increased significantly, dynamic recrystallization intensified, and the texture was further enhanced. The tensile strength reached 572.1 MPa, hardness was 369.6 HV, and elongation was 11.9%, representing improvements of 89.0%, 92.0%, and 142.9%, respectively, compared to the as-cast matrix alloy. Fracture surface analysis exhibited brittle fracture characteristics in the matrix alloy, while the extruded composite with optimal parameters displayed distinct ductile fracture features. In the extruded aluminum matrix composite, the interface between GNPs and the matrix was clean, with mutual diffusion of Al and C atoms, achieving an excellent interfacial bonding state. The significant enhancement in mechanical properties of the extruded alloy was primarily attributed to grain refinement strengthening, dislocation strengthening, and load transfer strengthening by GNPs. Full article

Nanostructured oxide coatings play a critical role in determining molecular adsorption and desorption behavior on solid surfaces. In this study, we propose a rapid and simple method to estimate the apparent vapor pressure of fragrance compounds using a quartz crystal microbalance (QCM) sensor modified with a nanostructured silica surface. Here, the term “apparent vapor pressure” refers to the vapor pressure values predicted from the QCM response characteristics, which correlate quantitatively with reference data obtained from conventional thermodynamic calculations. The QCM responses of various fragrances were analyzed in relation to the adsorption–desorption dynamics occurring at the nanostructured interface. We found a quantitative relationship between the sensor responses and the reference vapor pressure values, with a mean absolute percentage error (MAPE) ranging from 19.3% to 220% depending on the compound. This correlation enables rapid evaluation of vapor pressure-related behavior without relying on conventional vapor pressure measurement methods. The results suggest that the surface nanostructure influences the adsorption–desorption balance governed by vapor pressure. This approach provides a practical and efficient means of evaluating the apparent vapor pressure of volatile compounds on nanostructured materials, offering insights into interfacial phenomena relevant to materials science and applied nanosciences. Full article