Journal of Composites Science

27 pages, 11213 KB

Open AccessArticle

Influence of Thermal Treatment and Rapid Air Cooling on Waste Rock Wool Fiber-Reinforced Cement Mortar for Enhanced Sustainability

by Gamal S. Abdelhaffez, Azza I. Anan, Mostafa Abdel-Bary Ebrahim and Amr B. ElDeeb

J. Compos. Sci. 2026, 10(7), 378; https://doi.org/10.3390/jcs10070378 - 22 Jul 2026

Viewed by 371

Abstract

The disposal of waste rock wool insulation materials has become an increasing environmental concern, while their reuse in cementitious composites remains insufficiently explored, particularly under elevated-temperature conditions. Moreover, limited information is available regarding the influence of fiber pretreatment on the residual mechanical performance [...] Read more.

The disposal of waste rock wool insulation materials has become an increasing environmental concern, while their reuse in cementitious composites remains insufficiently explored, particularly under elevated-temperature conditions. Moreover, limited information is available regarding the influence of fiber pretreatment on the residual mechanical performance of cementitious mortars after fire exposure. Therefore, this study investigates the effect of untreated rock wool fibers (URWFs) and hydrothermally treated rock wool fibers (TRWFs) on the mechanical and thermal performance of cementitious mortar. The waste fibers were hydrothermally treated by immersing 40 g of fibers in 1 L of water, stirring for 10 min, followed by filtration and oven drying at 105 °C for 24 h. Mortar specimens incorporating eight fiber dosages (2.5%, 5.0%, 7.5%, 10.0%, 12.5%, 15.0%, 17.5%, and 20.0% by weight of cement) were tested for compressive strength after 28 days of curing and after exposure to elevated temperatures of 400, 500, and 600 °C for 2 h, followed by natural air cooling. The results demonstrated that hydrothermal treatment significantly enhanced the residual compressive strength of fiber-reinforced mortars compared with untreated fibers, with the greatest improvement observed after exposure to high temperatures. The optimum fiber content (2.5–5.0%) provided the highest retained strength ratio, improving residual compressive strength by 25.1% compared with the corresponding URWF, while exhibiting a retained strength ratio of 54.8%, slightly exceeding the control mixture 54.5%. TRWF mortars also exhibited lower water absorption of up to 18% reduction, and lower densities of up to 60% reduction compared to URWF mortars, indicating improved matrix densification, fiber–matrix bonding, and thermal stability. These findings demonstrate that hydrothermal treatment is an effective and sustainable approach for upgrading waste rock wool fibers into value-added reinforcement for lightweight, low-permeability cementitious mortars with improved fire resistance. The study is limited to compressive strength evaluation, and future work should investigate tensile and flexural behavior, ductility, energy absorption, crack propagation, and long-term durability. Full article

(This article belongs to the Special Issue Advanced Fiber Composites for a Sustainable Built Environment)

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27 pages, 12423 KB

Open AccessArticle

Physics-Guided Feature Engineering and Synthetic Data Augmentation for Machine Learning Prediction of Chloride Diffusion in Concrete

by Moutaman M. Abbas

J. Compos. Sci. 2026, 10(7), 377; https://doi.org/10.3390/jcs10070377 - 21 Jul 2026

Viewed by 344

Abstract

Chloride-induced corrosion is one of the principal causes of deterioration in reinforced concrete infrastructure, making accurate prediction of chloride diffusion coefficients essential for durability assessment and service-life design. Existing machine learning models often suffer from limited experimental datasets and insufficient incorporation of engineering [...] Read more.

Chloride-induced corrosion is one of the principal causes of deterioration in reinforced concrete infrastructure, making accurate prediction of chloride diffusion coefficients essential for durability assessment and service-life design. Existing machine learning models often suffer from limited experimental datasets and insufficient incorporation of engineering knowledge, restricting their predictive capability and generalization. This study presents a physics-guided machine learning framework that integrates domain-informed feature engineering, conditional synthetic data augmentation, and stacking ensemble learning to predict the chloride diffusion coefficient of concrete from Rapid Chloride Migration (RCM) test data. Physics-guided features were developed to represent fundamental transport mechanisms and binder characteristics, while synthetic data augmentation was employed to improve data coverage and enhance model robustness. The final stacking ensemble combined CatBoost, XGBoost, Random Forest, and Linear Regression through a Ridge Regression meta-learner. The proposed framework achieved a coefficient of determination (R²) of 0.903, with an RMSE of 1.321 and an MAE of 0.920 on an independent holdout dataset, outperforming all individual machine learning models. Ablation analysis demonstrated that synthetic data augmentation was the primary contributor to performance improvement, while ensemble learning provided additional gains in predictive accuracy and robustness. Model interpretability using SHapley Additive exPlanations (SHAP) identified slag content, water-to-binder ratio, and porosity-related variables as the dominant factors governing chloride diffusion predictions, consistent with established durability mechanisms. The proposed framework provides an accurate and interpretable tool for chloride diffusion prediction that supports durability assessment, service-life estimation, and the design of sustainable concrete mixtures. Full article

(This article belongs to the Section Composites Applications)

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30 pages, 8340 KB

Open AccessArticle

Symmetry-Driven Mechanical Response and Fracture Behavior of FDM-Printed PLA LW Structures: A Factorial Study of Infill Topology, Print Temperature, and Flow Rate with Macrographic Fractographic Validation

by Ahmad Alshwawra, Ali Fayoumi, Mohammad Hani Alomari and Nabilah Afiqah Mohd Radzuan

J. Compos. Sci. 2026, 10(7), 376; https://doi.org/10.3390/jcs10070376 - 18 Jul 2026

Viewed by 497

Abstract

Lightweight polylactic acid (PLA LW) is a thermally activated foaming filament in which print temperature governs the extent of in situ gas expansion. This dual role, as a microstructural design parameter and a primary source of performance variability, motivates the three-phase, multi-factorial experimental [...] Read more.

Lightweight polylactic acid (PLA LW) is a thermally activated foaming filament in which print temperature governs the extent of in situ gas expansion. This dual role, as a microstructural design parameter and a primary source of performance variability, motivates the three-phase, multi-factorial experimental program reported here. FDM-printed specimens of three infill topologies were investigated: orthogonal Cubic, hierarchical Subdivision Cubic (Sub-Cubic), and Gyroid triply periodic minimal surface (TPMS), each representing a distinct crystallographic symmetry class. A total of 504 specimens were fabricated across eight print temperatures (190–260 °C), three flow rate settings (70%, 80%, 100%), and four infill ratios (10%, 20%, 40%, 60%) and tested under quasi-static tensile and Charpy impact loading, with six replicates per condition distributed across two independent batches. One-way ANOVA confirmed a strong temperature effect on ultimate tensile strength (UTS) in Phase 1 (F(7,40) = 22.37, p < 0.001), while the Gyroid is uniquely temperature-sensitive in Phase 2 at 70% flow rate (F(1,8) = 14.30, p = 0.005) compared to the Cubic and Sub-Cubic, which exhibit no significant temperature effect in the 230–240 °C window. The Gyroid at 240 °C and 70% flow rate achieved the highest specific strength among Phase 2 configurations (20.9 MPa·cm³/g); Phase 3 demonstrated that Gyroid-specific strength decreases monotonically with the infill ratio, reaching 15.4, 12.3, and 8.8 MPa·cm³/g at 10%, 40%, and 60% infill, respectively. Cubic infill at 230 °C and 80% flow rate delivered the most reproducible performance (CV_UTS = 3.3%), while Sub-Cubic at the same condition combined high specific strength (20.5 MPa·cm³/g) with low variability (CV_UTS = 4.3%); both observations are quantified through a symmetry robustness index and a symmetry consistency indicator. Macrographic fractography supported geometry-controlled fracture: Cubic specimens fracture along layer interface mirror planes or ±45° shear planes depending on the thermal regime, while Gyroid specimens exhibit multi-plane, curvature-deflected fracture with no preferred crack propagation direction. These results indicate that geometric symmetry class is an important organizing factor for the mechanical response of FDM-printed PLA LW structures within the investigated parameter space. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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42 pages, 1599 KB

Open AccessSystematic Review

Durability of Geopolymer Concrete Under Chemical Attack: A Review of Acid, Sulfate, Chloride, and Multi-Exposure Resistance

by Mazen J. Al-Kheetan

J. Compos. Sci. 2026, 10(7), 375; https://doi.org/10.3390/jcs10070375 - 17 Jul 2026

Viewed by 391

Abstract

The durability of concrete in chemically aggressive environments remains a major concern for marine structures, wastewater systems, industrial facilities, pavements, and foundations exposed to sulfate-bearing soils. Geopolymer concrete has attracted increasing attention as a lower-carbon alternative to ordinary Portland cement concrete because its [...] Read more.

The durability of concrete in chemically aggressive environments remains a major concern for marine structures, wastewater systems, industrial facilities, pavements, and foundations exposed to sulfate-bearing soils. Geopolymer concrete has attracted increasing attention as a lower-carbon alternative to ordinary Portland cement concrete because its aluminosilicate-rich reaction products, reduced portlandite content, and adjustable precursor–activator chemistry may enhance resistance to various chemical attack mechanisms. However, its durability is strongly governed by mixture composition and exposure regime, and therefore cannot be generalized across all geopolymer systems. This review provides a systematic and critical synthesis of the chemical attack resistance of geopolymer concrete, focusing on acid, sulfate, chloride, marine, wastewater, and combined aggressive exposures. The effects of precursor chemistry, calcium content, activator composition, curing regime, additives, fibers, aggregate type, recycled materials, and environmental coupling are examined in relation to degradation mechanisms and durability indicators. A PRISMA-informed methodology was used to identify, screen, verify, and synthesize primary experimental and modeling studies. The reviewed evidence indicates that low-calcium and well-polymerized geopolymer systems often exhibit favorable sulfate resistance due to the reduced availability of calcium-bearing phases that form expansive products, whereas chloride resistance is primarily governed by pore refinement, chloride transport, binding capacity, pore–solution alkalinity, and reinforcement corrosion behavior. In contrast, acid resistance remains more variable, depending on acid type, pH, exposure duration, solution renewal, calcium content, and the stability of protective silica-rich layers. Additives and alternative aggregates can enhance durability by refining the pore structure, improving the interfacial transition zone, or controlling cracking, but excessive or incompatible dosages may have adverse effects. Overall, geopolymer concrete offers strong potential for chemically aggressive infrastructure when designed through performance-based criteria and validated under realistic multi-exposure conditions. Full article

(This article belongs to the Special Issue High-Performance Cementitious Composites: Materials Development, Smart Technologies, and Engineering Applications)

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19 pages, 26244 KB

Open AccessArticle

Drum Shell-Inspired Fractal Lightweight Microlattice Structures with Tailored Mechanical and Transport Properties

by Zhenbang Lei, Xuerui Xia, Jianle Zhang, Luobin Hu, Xu Wang and Lei Zhang

J. Compos. Sci. 2026, 10(7), 374; https://doi.org/10.3390/jcs10070374 - 17 Jul 2026

Viewed by 256

Abstract

Inspired by the mechanical principles governing efficient impact load transmission and dissipation in drum shells, this study proposes a novel hierarchical microlattice design strategy that integrates bionic concepts with fractal geometry, aiming to develop multifunctional microlattice structures combining superior mechanical performance with favorable [...] Read more.

Inspired by the mechanical principles governing efficient impact load transmission and dissipation in drum shells, this study proposes a novel hierarchical microlattice design strategy that integrates bionic concepts with fractal geometry, aiming to develop multifunctional microlattice structures combining superior mechanical performance with favorable fluid transport characteristics. Based on the hexagonal crystal structure (HCS), first- and second-order fractal designs were introduced to construct microlattice architectures of varying topological complexities, designated as F-HCS (first-order fractal HCS) and T-HCS (second-order fractal HCS), respectively. Ti-6Al-4V alloy specimens were fabricated via laser powder bed fusion (LPBF), and their mechanical responses and permeability characteristics were systematically investigated through quasi-static compression experiments and computational fluid dynamics (CFD) simulations. The results demonstrate that the second-order fractal architecture effectively optimizes stress distribution at nodal regions; under identical strut diameter conditions, its elastic modulus, yield strength, and energy absorption capacity significantly surpass those of the control structure. Nevertheless, the enhancement in topological complexity, while improving mechanical properties, concurrently increases fluid flow resistance and reduces permeability. This study quantitatively elucidates the intrinsic trade-off between mechanical performance and fluid transport in microlattice design, providing a critical theoretical basis for the rational design of multifunctional microlattices in integrated load-bearing and mass-transfer applications. Full article

(This article belongs to the Special Issue Lattice Structures)

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19 pages, 2039 KB

Open AccessArticle

Tailoring the Morphological and Transport Properties of PES–Activated Carbon Composites Through PEG Molecular Weight Modulation

by Jason Nathanael Thionardo, Muhammad Mirza Rahardianto, Asseghaf Bintang Ramadhani, Annas Zakky Firmansyah, Kartika Nur ‘Anisa, Chandrawati Putri Wulandari, Muslim Mahardika, Yudan Whulanza, Ario Sunar Baskoro, Thanongsak Thepsonthi, Nor Hasrul Akhmal Ngadiman and Gunawan Setia Prihandana

J. Compos. Sci. 2026, 10(7), 373; https://doi.org/10.3390/jcs10070373 - 16 Jul 2026

Cited by 1 | Viewed by 723

Abstract

The rising prevalence of chronic kidney disease (CKD) has intensified the demand for innovative blood filtration therapies. Hemoperfusion, which integrates membrane filtration with adsorbent technologies to sequester circulating uremic toxins, represents a promising therapeutic alternative. In this study, polyethersulfone (PES)-powdered activated carbon (PAC) [...] Read more.

The rising prevalence of chronic kidney disease (CKD) has intensified the demand for innovative blood filtration therapies. Hemoperfusion, which integrates membrane filtration with adsorbent technologies to sequester circulating uremic toxins, represents a promising therapeutic alternative. In this study, polyethersulfone (PES)-powdered activated carbon (PAC) composite membranes were fabricated via nonsolvent-induced phase separation (NIPS), and the molecular weight of polyethylene glycol (PEG) was optimized as a hydrophilic pore-forming agent. Dope solutions were formulated with 15 wt.% PES, 1 wt.% PAC, and 10 wt.% PEG at varying molecular weights (200, 400, 600, and 1000 Da). Comprehensive characterization revealed that PEG molecular weight significantly dictates the structural and functional performance of the resulting composites. The PEG 600 Da variant achieved an optimal balance of properties, characterized by homogeneous PAC dispersion, a peak water flux of 420.88 LMH/Bar, a water contact angle of 37.11°, and a porosity of 74.74%, while maintaining a high Bovine Serum Albumin (BSA) rejection of 90.87%. While increasing PEG molecular weight generally enhanced permeability through the formation of an open pore architecture, a performance trade-off was observed beyond the 600 Da threshold due to increased dope viscosity and altered phase inversion kinetics. These findings suggest that PEG 600-optimized PES-PAC membranes offer a high-performance, affordable platform for advanced hemoperfusion applications. Full article

(This article belongs to the Special Issue Polymer Composites: Technology and Sustainability)

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13 pages, 6499 KB

Open AccessArticle

Evaluation of Woven Hemp-Reinforced Polyfurfuryl Alcohol Resin Composites for High-Performance Natural Fibre Composite Applications

by Gilles Koolen, Dharmjeet Madhav, Alexandros Prapavesis, Jens Verbruggen, Xavier Gabrion, Briac Gricourt, Willem Bottger, Mark Lepelaar, Vincent Placet and Aart W. van Vuure

J. Compos. Sci. 2026, 10(7), 372; https://doi.org/10.3390/jcs10070372 - 15 Jul 2026

Viewed by 457

Abstract

The escalating environmental concerns associated with the non-renewable nature of petrochemical-based composite constituents have accelerated the development of sustainable and renewable alternatives. This study evaluates the potential of woven hemp-reinforced polyfurfuryl alcohol (PFA, furan) composites as fully bio-based composite materials. The use of [...] Read more.

The escalating environmental concerns associated with the non-renewable nature of petrochemical-based composite constituents have accelerated the development of sustainable and renewable alternatives. This study evaluates the potential of woven hemp-reinforced polyfurfuryl alcohol (PFA, furan) composites as fully bio-based composite materials. The use of PFA, a fully bio-based resin renowned for its high rigidity and fire-retardant properties, has been hindered by challenges associated with water vapour evolution, acid-catalysed fibre degradation, and porosity formation. Novel woven long hemp fibres were combined with a polyfurfuryl alcohol resin formulated with a mild acid catalyst, while an early-stage venting procedure during compression moulding was investigated to mitigate porosity and fibre degradation. Thermogravimetric analysis was used to determine the venting moments during the moulding cycle. Despite the limited improvement in porosity reduction achieved through the investigated venting strategy, the hemp balanced satin 6/6 fabric–furan composites exhibited commendable stiffness with a maximum modulus of 17.0 ± 0.4 GPa. However, the inherent brittleness of the resin and possibly the presence of fire-retardant fillers limited the tensile strength (a maximum of 71.8 ± 4.2 MPa) and failure strain (a maximum of 0.72 ± 0.07%). The bending properties of neat furan resin produced using an improved curing protocol were comparable to those of conventional thermoset resins, with a modulus of 3.2 ± 0.2 GPa, strength of 110.5 ± 17.3 MPa, and failure strain of 4.1 ± 0.8%. Although several challenges remain, this study demonstrates the potential of natural fibre–furan composites for high-performance natural fibre composite applications and provides guidance for their further development. Future research should focus on optimising venting strategies, avoiding fire retardants to minimise resin brittleness, incorporating matrix tougheners, and enhancing the inherent toughness of the matrix. Full article

(This article belongs to the Special Issue Sustainable Polymer Composites: Waste Reutilization and Valorization)

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29 pages, 8789 KB

Open AccessArticle

An Intelligent CRITIC–WASPAS Decision Framework for Sustainable Multi-Material Additive Manufacturing of Architected Structures

by Raja Subramani and Mohamad Reda A. Refaai

J. Compos. Sci. 2026, 10(7), 371; https://doi.org/10.3390/jcs10070371 - 12 Jul 2026

Viewed by 857

Abstract

Functionally graded multi-material architected structures fabricated by fused deposition modeling (FDM) were investigated to evaluate their multifunctional mechanical and dynamic performance. Sixteen honeycomb configurations incorporating poly(lactic acid) (PLA), thermoplastic polyurethane (TPU), and wood-filled PLA (WWF-PLA) were designed by systematically varying material distribution, cellular [...] Read more.

Functionally graded multi-material architected structures fabricated by fused deposition modeling (FDM) were investigated to evaluate their multifunctional mechanical and dynamic performance. Sixteen honeycomb configurations incorporating poly(lactic acid) (PLA), thermoplastic polyurethane (TPU), and wood-filled PLA (WWF-PLA) were designed by systematically varying material distribution, cellular geometry, and structural density as integrated architected configurations. Compression, flexural, dynamic mechanical, free-vibration, density reduction, and water absorption tests were conducted, and the experimental responses were objectively evaluated using the CRITIC–WASPAS multi-criteria decision-making framework. Among the investigated configurations, A16 exhibited the highest overall performance, achieving 41.8 MPa compressive strength, 56.4 MPa flexural strength, 1425 MPa storage modulus, 0.162 loss factor (tan δ), 3.7% damping ratio, and 39% density reduction. Compared with the baseline configuration (A1), A16 demonstrated improvements of 14.5%, 17.0%, 20.8%, 44.6%, 76.2%, and 77.3% in the respective performance metrics. The proposed framework provides an objective approach for ranking integrated architected designs for lightweight multifunctional engineering applications. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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17 pages, 2561 KB

Open AccessArticle

Electronic Structure Modulation in Sulfur-Doped g-C₃N₄ Quantum Dots for Enhanced NO₂ Sensing

by Kriengkri Timsorn, Yaowapa Saengpayab and Chatchawal Wongchoosuk

J. Compos. Sci. 2026, 10(7), 370; https://doi.org/10.3390/jcs10070370 - 11 Jul 2026

Viewed by 470

Abstract

This study explores the adsorption behavior of NO₂, NO, and N₂O gas molecules on pristine and sulfur-doped g-C₃N₄ quantum dots using the self-consistent charge density functional tight-binding (SCC-DFTB) method. Sulfur doping at the energetically favorable N-ring [...] Read more.

This study explores the adsorption behavior of NO₂, NO, and N₂O gas molecules on pristine and sulfur-doped g-C₃N₄ quantum dots using the self-consistent charge density functional tight-binding (SCC-DFTB) method. Sulfur doping at the energetically favorable N-ring site significantly alters the electronic structure, reducing the band gap from 3.58 eV to 1.37 eV and increasing the density of states near the Fermi level. Adsorption analysis reveals that pristine g-C₃N₄ exhibits weak physisorption toward all gases, whereas S/g-C₃N₄ demonstrates a transition from physisorption to strong chemisorption, especially for NO₂, with adsorption energies as high as −3.543 eV. This strong interaction is associated with significant charge transfer and pronounced band gap narrowing to as low as 0.46 eV. Density of states analysis confirms the formation of hybridized electronic states near the Fermi level, which facilitates enhanced charge transfer and conductivity modulation. Among the studied gases, NO₂ shows the most significant electronic response, while NO exhibits moderate interaction and N₂O remains weakly adsorbed with negligible electronic perturbation. These findings indicate that sulfur doping plays a critical role in inducing electronic structure modulation and enables highly sensitive and selective NO₂ detection in g-C₃N₄ quantum dots. Full article

(This article belongs to the Special Issue Theoretical and Computational Investigation on Composite Materials, 2nd Edition)

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14 pages, 16916 KB

Open AccessArticle

Solid-Phase Synthesis of Na₃V₂(PO₄)₃/C Composite for Cathode Materials of Sodium-Ion Batteries

by Ilya Sidorov, Valery Zhylinski, Sergei Kusmanov, Alexey Vereschaka, Ihar Razanau and Sergey Grigoriev

J. Compos. Sci. 2026, 10(7), 369; https://doi.org/10.3390/jcs10070369 - 10 Jul 2026

Viewed by 466

Abstract

The aim of this article was to improve the solid-phase synthesis of Na₃V₂(PO₄)₃/C composite for sodium-ion battery cathode materials using an innovative technique for creating a protective reducing atmosphere, which is formed by incomplete oxidation [...] Read more.

The aim of this article was to improve the solid-phase synthesis of Na₃V₂(PO₄)₃/C composite for sodium-ion battery cathode materials using an innovative technique for creating a protective reducing atmosphere, which is formed by incomplete oxidation of carbon fiber during annealing. The resulting Na₃V₂(PO₄)₃ phase has a rhombohedral structure of a sodium superionic conductor (NASICON) with particle sizes ranging from 0.5 to 20.0 μm. The encapsulation of Na₃V₂(PO₄)₃ granules with a carbon coating leads to a maximum specific capacity of 112.3 mAh g⁻¹ at a charge–discharge rate of C/5 (22.4 mA g⁻¹). After 200 charge–discharge cycles, the synthesized composite demonstrated a specific discharge capacity degradation of 0.107% per cycle. The apparent diffusion coefficients of Na⁺ ions in the resulting Na₃V₂(PO₄)₃/C composite were measured and found to be 5.87 × 10⁻¹¹ and 4.60 × 10⁻¹¹ cm² s⁻¹ for deintercalation and intercalation, respectively. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Electrochemical Composites)

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24 pages, 3502 KB

Open AccessArticle

Dynamic Mechanical Response of PA12-GTR Composites Utilized with Selective Laser Sintering Additive Manufacturing

by Ioannis Fillipos Kyriakidis, Thomas Panagiotopoulos, Nikolaos Kladovasilakis, Apostolos Korlos, Dimitrios Tzetzis, Eleftheria Maria Pechlivani and Konstantinos Tsongas

J. Compos. Sci. 2026, 10(7), 368; https://doi.org/10.3390/jcs10070368 - 9 Jul 2026

Viewed by 409

Abstract

Waste material valorization as a feedstock for net-zero waste manufacturing processes has emerged as a key sustainability strategy. Process technologies such as Additive Manufacturing (AM) have helped to limit material waste and allowed the production of complex designs with lower required costs and [...] Read more.

Waste material valorization as a feedstock for net-zero waste manufacturing processes has emerged as a key sustainability strategy. Process technologies such as Additive Manufacturing (AM) have helped to limit material waste and allowed the production of complex designs with lower required costs and less time than other conventional manufacturing methods. In this study, an investigation of the addition of end-of-life Ground Tire Rubber (GTR) waste to a Polyamide 12 (PA12, nylon 12) matrix was conducted. Three different PA12-based powders were produced in a lab-scale environment with different weight fractions (wt.%) of reused GTR and specimens for static tensile, cyclic tensile, compression testing, Dynamic Mechanical Analysis (DMA), and vibrational analysis were designed assessing both the static and dynamic mechanical response. The specimens were 3D printed using Selective Laser Sintering (SLS) AM, a technique that promotes thermal coalescence between adjacent powder particles and successive layers, resulting in a more interconnected material structure and potentially reduced directional anisotropy compared to Fused Filament Fabrication (FFF) AM, although process-induced anisotropy may still be present, while the material used has a low powder refresh requirement of 22%. The results showed that the introduction of reused GTR helped improve the damping properties of the material. Combining the strength of PA12 even at high thermal stresses with the increasing damping properties of the GTR can be vital for vibration isolators in industrial, structural, and automotive applications while simultaneously reducing the material footprint. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites, 2nd Edition)

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39 pages, 2304 KB

Open AccessReview

Life Cycle Assessment of 3D Concrete Printed Buildings: A Review of Methodologies, Standards and EPBD Compliance

by Daniel Harris, Suleman Ayub Khan, Swathi Balasubramanian, Mamoun Alqedra, Mehran Khan and Ciaran McNally

J. Compos. Sci. 2026, 10(7), 367; https://doi.org/10.3390/jcs10070367 - 9 Jul 2026

Viewed by 548

Abstract

3D concrete printing (3DCP) is an emerging modern method of construction with potential to improve construction efficiency, reduce labour requirements, and support the delivery of sustainable housing. In Ireland, its recent adoption coincides with increasing policy emphasis on modern methods of construction and [...] Read more.

3D concrete printing (3DCP) is an emerging modern method of construction with potential to improve construction efficiency, reduce labour requirements, and support the delivery of sustainable housing. In Ireland, its recent adoption coincides with increasing policy emphasis on modern methods of construction and the introduction of stricter European requirements for assessing the climate impact of buildings. The recast Energy Performance of Buildings Directive (EPBD) introduces progressive requirements for the calculation and reporting of whole-life Global Warming Potential (GWP) for new buildings, creating a need for Life Cycle Assessment (LCA) methodologies aligned with current regulatory requirements and capable of capturing the specific characteristics of emerging construction technologies. This paper reviews the applicability of the EPBD, EN 15978, EN 15804, Level(s), and relevant Irish methodologies to 3DCP buildings. It also examines existing LCA studies on 3DCP and evaluates their methodological scope, system boundaries, functional units, data sources, and alignment with current regulatory requirements. The review shows that most existing 3DCP LCA studies remain focused on materials, components, or limited life-cycle stages, with cradle-to-gate assessments being particularly common. Consequently, many published studies do not fully align with the whole-building, cradle-to-grave assessment framework introduced under the revised EPBD.. The review also identifies a lack of LCA methodologies specifically tailored to 3DCP buildings, particularly in relation to printable material design, construction-process energy consumption, material efficiency, reinforcement strategy, durability, maintenance, and end-of-life scenarios. These gaps limit the comparability and regulatory relevance of current sustainability assessments. The paper concludes that EPBD-compliant whole-life carbon assessments of complete 3DCP buildings are urgently needed, alongside the development of 3DCP-specific methodological guidance and data to support reliable environmental benchmarking and wider adoption of the technology in Ireland and Europe. Full article

(This article belongs to the Special Issue Automated and Digital Construction of Low-Carbon and High-Performance Steel-Concrete Composite Systems)

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20 pages, 5150 KB

Open AccessArticle

Effect of Gap Distance on Shock Transmission to a Protected Target in a Multilayered Ceramic–Polymer–Metal Composite System

by Sabal Panthee, Prabesh Ojha, Huadian Zhang, Arunachalam M. Rajendran, Manoj K. Shukla, Steven Larson and Shan Jiang

J. Compos. Sci. 2026, 10(7), 366; https://doi.org/10.3390/jcs10070366 - 9 Jul 2026

Viewed by 792

Abstract

Shock wave propagation in a layered ceramic–polymer–metal (CPM) composite armor was investigated numerically using the Abaqus^© (2024) software in a plate-impact configuration, in which a copper impactor impacts a CPM plate that serves as an intermediate layer between the impactor and a [...] Read more.

Shock wave propagation in a layered ceramic–polymer–metal (CPM) composite armor was investigated numerically using the Abaqus^© (2024) software in a plate-impact configuration, in which a copper impactor impacts a CPM plate that serves as an intermediate layer between the impactor and a protected target representing human bone. The resulting motion of the CPM back surface closes a pre-calibrated gap, initiating a secondary impact on the protected target. Because the transmitted loadings depend on the complex interaction of compressive and release waves within the layered system, the effect of gap distance on impact response is difficult to predict. Therefore, the primary objective of this study is to develop an improved understanding of the shock-mitigation mechanisms within the CPM system that enable the target to survive the impact event. The particle-velocity history at the midplane of the protected target was used to compare responses at different gap distances. The gap effect is influenced by geometry under uniaxial strain conditions, as well as by the materials’ wave speed and shock impedance. The observed trends arise from the combined effects of geometry under uniaxial strain conditions, material wave speed, and shock impedance mismatch, which govern the evolution and interaction of the compressive and release waves at different gap distances. The CPM configuration was examined over a 1–10 mm gap, and a detailed analysis was conducted for the representative gap distances of 1–3 mm. The results indicate that the midplane velocity of the protected target depends strongly on the gap distance, with a 1 mm gap producing the highest midplane velocity, followed by gaps of 3 mm and 2 mm. The CPM response depends on differences in the timing and strength of compressive and release waves reaching its free surface before gap closure, as shown by velocity histories and x–t diagrams. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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15 pages, 4627 KB

Open AccessArticle

Balanced Solvation and Ion Transport in a Salt-Regulated Ether Electrolyte for Fast-Charging Li-Ion Batteries

by Shenao Liu, Xinglin Jiang, Hao Li, Qi Sun and Haitao Zhang

J. Compos. Sci. 2026, 10(7), 365; https://doi.org/10.3390/jcs10070365 - 8 Jul 2026

Viewed by 462

Abstract

Fast-charging graphite-based lithium-ion batteries (LIBs) are limited by sluggish Li⁺ desolvation, interfacial charge transfer, and solid-state diffusion in graphite (Gr). Herein, a salt-concentration-regulated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1,3-dioxolane (DOL) and fluoroethylene carbonate (FEC) electrolyte is developed to construct an anion-involved solvation structure [...] Read more.

Fast-charging graphite-based lithium-ion batteries (LIBs) are limited by sluggish Li⁺ desolvation, interfacial charge transfer, and solid-state diffusion in graphite (Gr). Herein, a salt-concentration-regulated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1,3-dioxolane (DOL) and fluoroethylene carbonate (FEC) electrolyte is developed to construct an anion-involved solvation structure for fast-charging graphite-based LIBs. At an appropriate LiTFSI concentration, TFSI⁻ is incorporated into the primary Li⁺ solvation sheath, forming a contact-ion-pair (CIP)-dominated solvation structure. The optimized electrolyte exhibits a Li⁺ transference number of 0.76 and an exchange current density of 0.28 mA cm⁻², indicating accelerated Li⁺ transport and interfacial charge transfer. Furthermore, a more uniform interfacial Li⁺ flux distribution is obtained, contributing to suppressed localized Li growth. As a result, Gr||Li half cells deliver 168 mAh g⁻¹ at 10 C (1 C = 370 mAh g⁻¹). LFP||Gr full cells with an LiFePO₄ (LFP) areal capacity of 4 mAh cm⁻² deliver 115 mAh g⁻¹ at 2 C and retain 69% capacity after 200 cycles. This work highlights moderate salt-concentration regulation in DOL/FEC electrolytes as an effective strategy for fast graphite lithiation without relying on fluorinated ether solvents or localized high-concentration formulations. Full article

(This article belongs to the Special Issue Composite Materials for Energy Management, Storage or Transportation)

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20 pages, 31616 KB

Open AccessArticle

Mechanical Performance of Modified Polyurea Lining for Rehabilitation of Aging Urban Underground Concrete Drainage Pipes

by Chen Gong, Xiaochun Ma, Lei Yu, Xiaochuan Li, Li Long, Xu Kong, Jinglong Wu, Yan Shang and Jiyuan Ding

J. Compos. Sci. 2026, 10(7), 364; https://doi.org/10.3390/jcs10070364 - 7 Jul 2026

Viewed by 548

Abstract

Aging and deterioration of urban underground drainage pipelines frequently trigger road collapses, urban waterlogging and groundwater contamination, posing critical challenges to the operation, maintenance and disaster prevention of urban underground infrastructure. Conventional rehabilitation solutions, including cement-based linings and traditional polymer liners, suffer from [...] Read more.

Aging and deterioration of urban underground drainage pipelines frequently trigger road collapses, urban waterlogging and groundwater contamination, posing critical challenges to the operation, maintenance and disaster prevention of urban underground infrastructure. Conventional rehabilitation solutions, including cement-based linings and traditional polymer liners, suffer from inherent limitations such as reduced effective flow cross-sections caused by excessive lining thickness, unsatisfactory corrosion resistance and durability, and high construction disturbance. In this study, a modified polyurea (MPU) material was applied to the trenchless rehabilitation of drainage pipelines via spray-applied pipe lining technology. The mechanical properties and interfacial bonding performance of MPU were systematically characterized at the material scale; full-scale external pressure tests were conducted to investigate the effects of 3–8 mm thick MPU linings on the bearing capacity and failure characteristics of structurally damaged concrete pipes; and the anti-seepage repair performance for local perforation defects was evaluated through void-crossing testing. The results demonstrate that MPU lining can meet the engineering performance requirements for pipeline rehabilitation when applied with matched interfacial primer following standard construction procedures. Even the baseline bond strength tested without primer remains sufficient to ensure stable cooperative load bearing between the lining and the host concrete pipe. The 3–8 mm thick linings increase the cracking load of damaged pipes by 61.7–145.7% and the ultimate load by up to 162.2%, while transforming the failure mode from brittle fracture to ductile failure. For local perforation repair, the 3 mm thick MPU lining achieves a critical hydrostatic failure pressure of 1.23 MPa, maintaining favorable structural integrity and interfacial bonding stability under the test conditions. With a well-balanced combination of thin lining thickness, rapid curing and high structural strengthening efficiency, as well as favorable inherent corrosion resistance, the MPU lining provides novel material alternatives and fundamental experimental evidence for the green trenchless rehabilitation of aged underground pipelines and offers technical support for the safe operation and maintenance of urban underground infrastructure. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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29 pages, 2998 KB

Open AccessArticle

Towards Full Orthotropy in Laminated Composites: The Tailored Antisymmetric Concept

by Antonio Miravete, Juan M. Mejia-Ariza and Jesus Cuartero

J. Compos. Sci. 2026, 10(7), 363; https://doi.org/10.3390/jcs10070363 - 7 Jul 2026

Viewed by 439

Abstract

Orthotropic laminates are highly desirable in composite structures because they eliminate bending–twisting coupling, simplify structural behavior, improve analytical predictability, and facilitate structural design, optimization, and certification. However, achieving fully orthotropic behavior in laminated composites remains challenging because conventional laminate architectures generally retain stiffness [...] Read more.

Orthotropic laminates are highly desirable in composite structures because they eliminate bending–twisting coupling, simplify structural behavior, improve analytical predictability, and facilitate structural design, optimization, and certification. However, achieving fully orthotropic behavior in laminated composites remains challenging because conventional laminate architectures generally retain stiffness couplings arising from anisotropic ply orientations and stacking-sequence effects. This work introduces the Tailored Antisymmetric Composite (TAC) concept, a laminate architecture that provides the closest practical approximation to full orthotropy while preserving broad stiffness-tailoring capability and manufacturability. TAC laminates are constructed from tailored antisymmetric sublaminates that enforce

D_{16} = D_{26} = 0

while maintaining extremely small extension–bending coupling terms

B_{16}

and

B_{26}

. Representative TAC and symmetric Quad laminates were compared analytically, statistically, and experimentally. Monte Carlo simulations comprising 100,000 realizations with realistic ±0.1° AFP/ATL fiber-orientation deviations showed that the distributions of the extension–bending coupling terms

B_{16}^{*}

and

B_{26}^{*}

remained nearly indistinguishable for both laminate architectures, with probability-density overlap coefficients between 0.87 and 0.98. In contrast, the bending–twisting coupling terms

D_{16}^{*}

and

D_{26}^{*}

were 140–600 times lower in TAC laminates than in the corresponding Quad laminates, and their statistical distributions exhibited complete separation. Experimental measurements of post-cure warpage confirmed that TAC laminates achieved dimensional stability comparable to symmetric Quad laminates while exhibiting lower variability. These results demonstrate that TAC laminates combine exact elimination of bending–twisting coupling with negligible extension–bending coupling, statistical robustness to realistic manufacturing variability, and excellent dimensional stability, establishing TAC as a practical and systematic route toward full orthotropy in laminated composite structures. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Modeling and Simulation of Composite Materials, 2nd Edition)

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19 pages, 5828 KB

Open AccessArticle

Preparation and Investigating the Physical, Mechanical and Thermal Performances of Sand/Soil/Recycled HDPE Composites

by Etienne Malbila, Decroly Djoubissié Denouwé, Sabour Compaore, Dieudonné Dabilgou and Adamah Messan

J. Compos. Sci. 2026, 10(7), 362; https://doi.org/10.3390/jcs10070362 - 7 Jul 2026

Viewed by 477

Abstract

The recycling of waste into materials is a form of recovery that offers a double advantage, such as eco-sustainable sanitation and the availability of new ecological construction materials in Civil Engineering. The present study aimed to develop a composite eco-material based on sand, [...] Read more.

The recycling of waste into materials is a form of recovery that offers a double advantage, such as eco-sustainable sanitation and the availability of new ecological construction materials in Civil Engineering. The present study aimed to develop a composite eco-material based on sand, soil and recycled plastic waste melted using a Scheffler solar concentrator (SSC). Then, two types of mix were formulated: a sand/PW mix with ratios of 75/25, 70/30, 65/35 and 60/40, and a sand/soil/PW mix with a ratio of 60/30/10. The SSC enabled an internal melting temperature of 172.42 °C to be reached. Specimens measuring 4 × 4 × 16 cm³ were made and tested using 3-point bending, compression, capillary absorption and thermal tests. The best mechanical resistance was obtained with the 65/35 ratio of the sand/PW mix, with average values of 12.15 MPa in 3-point bending and 23.96 MPa in compression. This composite eco-material had a water absorption rate of 0.4% and a thermal diffusivity of 0.36 mm²/s. On the other hand, the sand/PW/laterite mix had a mechanical strength of 10.1 MPa in 3-point bending and 22.83 MPa in compression, with a water absorption rate of 2.3% and a thermal diffusivity of 0.44 mm²/s. In addition to these initial results, we plan to analyze the effect of thermal shock or wetting-drying cycles on the durability of this composite eco-material. As these properties comply with the established standards, the sand/soil/recycle HPDE composites can be used for applications such as pavers and tiles for interior flooring, and hollow and solid blocks. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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18 pages, 1748 KB

Open AccessArticle

A Study of Certain Strength Properties of Wood–Concrete Composites

by Baizak Isakulov, Abilkhair Issakulov, Kamar Dzhumabaeva, Nuradil Sarsenbay and Khamid Abdullayev

J. Compos. Sci. 2026, 10(7), 361; https://doi.org/10.3390/jcs10070361 - 7 Jul 2026

Viewed by 753

Abstract

This paper examines certain strength characteristics of wood–concrete composites in comparison with other lightweight concretes. To address these issues, we conducted a series of experiments to study the relationship between the prismatic strength-to-cubic strength ratio, the development of strength, and the sequence of [...] Read more.

This paper examines certain strength characteristics of wood–concrete composites in comparison with other lightweight concretes. To address these issues, we conducted a series of experiments to study the relationship between the prismatic strength-to-cubic strength ratio, the development of strength, and the sequence of failure stages in arbolite–concrete composites with various structural characteristics under a destructive load. Our experiments confirmed that the ratio of cubic to prismatic strength in wood–concrete specimens ranges from 0.894 to 0.965 and, in some cases, approaches unity depending on the size, fibers, and microstructure of the organic aggregate. We have also established that the failure of fibrous-structured arbolite concrete specimens occurs sequentially: first, the mortar component fails, and then the organic aggregate fibers fail. In arbolite concrete specimens with a porous and coarse-pored structure, failure occurs simultaneously, as in other types of concrete. Based on the characteristics of the hardening and failure stages of arbolite–concrete composites, they can be used as wall material for building construction in regions with high seismic activity. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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23 pages, 3300 KB

Open AccessArticle

Free Vibrations and Thermal Vibrations of Thick FGM Spherical Shells Triggered by Sinusoidal Temperature Field

by Chih-Chiang Hong

J. Compos. Sci. 2026, 10(7), 360; https://doi.org/10.3390/jcs10070360 - 6 Jul 2026

Viewed by 338

Abstract

Studies of third-order shear-deformation theory (TSDT) and an advanced shear coefficient for thick-walled functionally graded material (FGM) spherical shells subjected to thermal vibrations triggered by sinusoidal temperature are presented. The nonlinear TSDT and linear and nonlinear shear coefficient can be converted into fully [...] Read more.

Studies of third-order shear-deformation theory (TSDT) and an advanced shear coefficient for thick-walled functionally graded material (FGM) spherical shells subjected to thermal vibrations triggered by sinusoidal temperature are presented. The nonlinear TSDT and linear and nonlinear shear coefficient can be converted into fully homogeneous equation algorithms under the sinusoidal form of free vibrations to obtain the fundamental natural frequency by using Newton’s numerical method. Then, the generalized differential quadrature (GDQ) method can be used to prepare dynamic discrete equations of motion triggered by sinusoidal temperature field in thick FGM spherical shells for materials SUS304 and Si₃N₄. The Young’s modulus expressed as a power-law function of thick FGM spherical shells is considered and subjected to applied thermal load. The response results of thermal stress and center displacement are compared for the cases of linear and nonlinear advanced shear coefficient, and simply and fully homogeneous equation algorithms, respectively. The practical insights for temperature effect considered in the calculation of stress and displacement are very clear and practical for FGM structures with geometries of spherical shells. The power-law function property of FGMs can be used under high temperature for four-sided simply supported constraints. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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26 pages, 6757 KB

Open AccessArticle

Influence of Hydrated Lime on Hydration Products, Phase Assemblage, and Mechanical Performance of Cement-Based Mortars

by Rafael C. Manta, Daniel Silva, William Costa, Paulo R. L. Souza, Priscila Vilemen, Leonardo B. T. Santos, Esdras C. Costa, Bruno S. Teti, Nathalia B. D. Lima and Nathan B. Lima

J. Compos. Sci. 2026, 10(7), 359; https://doi.org/10.3390/jcs10070359 - 6 Jul 2026

Viewed by 547

Abstract

Hydrated lime is widely incorporated into cement-based mortars to improve workability and fresh-state properties; however, its influence on hydration products and mechanical performance remains insufficiently understood. This study investigates the effect of hydrated lime content on the mechanical behavior and microstructural development of [...] Read more.

Hydrated lime is widely incorporated into cement-based mortars to improve workability and fresh-state properties; however, its influence on hydration products and mechanical performance remains insufficiently understood. This study investigates the effect of hydrated lime content on the mechanical behavior and microstructural development of cement-based mortars after 28 days of curing. Eight mortar formulations, ranging from lime-free (1:0:6) to lime-rich (1:5:6) mixtures, including intermediate and modified proportions, were evaluated through compressive strength, flexural tensile strength, and consistency tests. The microstructural evolution was investigated using complementary techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG/DSC), and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS). Increasing hydrated lime content improved mortar workability but was generally associated with reduced compressive strength under the curing conditions investigated. The combined characterization techniques indicated progressive modifications in the hydration products and phase assemblage, with increased calcium-rich phases, greater evidence of carbonation, and reduced continuity of the hydraulic matrix as the hydrated lime content increased. The observed microstructural changes were qualitatively consistent with the mechanical behavior of the mortars. The conclusions of this study are restricted to the 28-day curing period investigated, and further research is required to evaluate the long-term influence of hydrated lime on carbonation and durability-related properties. These findings contribute to a better understanding of the role of hydrated lime in cement-based mortars and provide experimental evidence for the optimization of mortar formulations. Full article

(This article belongs to the Special Issue High-Performance Cementitious Composites: Materials Development, Smart Technologies, and Engineering Applications)

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24 pages, 1657 KB

Open AccessReview

Interfacial-State and Transport-Barrier Competition in Electrochemically Deposited PANI Nanocomposites: A Unified Theoretical Framework for Bandgap Evolution, Disorder, Dielectric Dispersion, Nonlinear Optics, and DC Conductivity

by Mahmoud AlGharram, Tariq AlZoubi, Yahia Makableh and Jestin Mandumpal

J. Compos. Sci. 2026, 10(7), 358; https://doi.org/10.3390/jcs10070358 - 4 Jul 2026

Viewed by 532

Abstract

This review analyzes electrochemically deposited polyaniline (PANI) nanocomposite thin films containing metallic, semiconducting, and dielectric fillers, including Ag/PANI, Mo/MoO_x/PANI, CeO₂/PANI, Fe₂O₃/PANI, Al₂O₃/PANI, CuO/PANI, Co₃O₄/PANI, and CoFe₂ [...] Read more.

This review analyzes electrochemically deposited polyaniline (PANI) nanocomposite thin films containing metallic, semiconducting, and dielectric fillers, including Ag/PANI, Mo/MoO_x/PANI, CeO₂/PANI, Fe₂O₃/PANI, Al₂O₃/PANI, CuO/PANI, Co₃O₄/PANI, and CoFe₂O₄/PANI. The work examines how filler chemistry and loading influence optical-gap evolution, Urbach disorder, dielectric dispersion, nonlinear optical response, structural coherence, and dc conductivity under comparable electrochemical growth conditions. The comparative analysis shows that optical-gap narrowing and conductivity enhancement are not necessarily coupled. Ag/PANI exhibits simultaneous optical softening and improved conductivity, consistent with metallic bridging, dielectric screening, and enhanced charge connectivity. In contrast, Mo/MoO_x/PANI shows strong optical-gap reduction but reduced conductivity, indicating that optically active interfacial states may remain localized or mobility-limiting. Oxide fillers produce additional regimes: CeO₂/PANI can suppress Urbach disorder and microstrain through order stabilization, whereas Al₂O₃/PANI may widen higher-energy transitions and reduce transport through wide-gap barrier effects. Based on these contrasts, a unified framework is proposed that separates the interfacial electronic function from the transport-connectivity function. This approach classifies PANI nanocomposites into transport-assisted metallic, mobility-limiting interfacial, order-stabilized oxide, and barrier-dominated dielectric regimes, providing practical criteria for selecting filler type and loading windows in optoelectronic, sensing, and photonic applications. Full article

(This article belongs to the Section Nanocomposites)

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24 pages, 6166 KB

Open AccessArticle

Shear Strengthening of RC T-Beams Using Externally Bonded UHPC Composite Layers with Steel Plates and Geotextiles

by Mustafa Shareef Zewair, Ahid Zuhair Hamoodi, Hawraa S. Malik and Kadhim Z. Naser

J. Compos. Sci. 2026, 10(7), 357; https://doi.org/10.3390/jcs10070357 - 3 Jul 2026

Cited by 1 | Viewed by 554

Abstract

This study presents an experimental investigation of reinforced concrete T-beams strengthened using ultra-high-performance concrete (UHPC) with steel plates, and in some cases, UHPC with a geotextile layer. Ten reinforced concrete specimens with the same internal reinforcement but different strengthening methods were tested. These [...] Read more.

This study presents an experimental investigation of reinforced concrete T-beams strengthened using ultra-high-performance concrete (UHPC) with steel plates, and in some cases, UHPC with a geotextile layer. Ten reinforced concrete specimens with the same internal reinforcement but different strengthening methods were tested. These included a control specimen and nine strengthened specimens. Four of the strengthened specimens had grooves in the wooden formwork before pouring to secure the strengthening composite plates inside it, four had it directly attached to the RC beam surface, and the last had vertical lines 10 mm deep to enhance bonding. The external composite plate consisted of four types: the first type included a composite of UHPC and steel plates as strips with 220 × 150 mm at 105 mm, while the remaining types consisted of a plate along the shear zones made of UHPC with steel, geotextiles, or steel and geotextiles. This study also included increasing the number of steel plate layers and the direction of strengthening placement. The results showed that all the strengthened beams failed in flexure, unlike the control specimen, which failed in shear. The strengthening systems improved the load-bearing capacity and overall structural behavior of the tested beams. Among the investigated specimens, beam IR-2S90SS, strengthened with two layers of steel plates, showed the highest improvement, achieving a 39.2% increase in ultimate load compared to the control beam. Debonding was observed in some specimens and was identified as one of the governing failure mechanisms. Overall, the investigated strengthening techniques demonstrated their effectiveness in improving the structural performance of reinforced T-beams. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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26 pages, 34839 KB

Open AccessArticle

Microstructure–Property Relationships in Epoxy Matrices Modified with Portland Cement and Microsilica

by Sergey A. Stel’makh, Evgenii M. Shcherban’, Alexey N. Beskopylny, Diana M. Shakhalieva, Andrei Chernil’nik, Ivan Vialikov, Natalya Shcherban’, Anastasia Tyutina and Yasin Onuralp Özkılıç

J. Compos. Sci. 2026, 10(7), 356; https://doi.org/10.3390/jcs10070356 - 3 Jul 2026

Viewed by 811

Abstract

In this study, the effect of the epoxy resin and mineral filler ratio on the density, compressive strength, flexural strength, water absorption, and structure of polymer matrices was investigated. The combined effect of Portland cement and microsilica on the structure–property relationship of epoxy [...] Read more.

In this study, the effect of the epoxy resin and mineral filler ratio on the density, compressive strength, flexural strength, water absorption, and structure of polymer matrices was investigated. The combined effect of Portland cement and microsilica on the structure–property relationship of epoxy matrices remains insufficiently understood. The control mixture was made from 100% epoxy resin with a hardener. Various types of mineral fillers, Portland cement (PC), microsilica (MS) and their mixtures were introduced by volume from 0 to 50% in increments of 10%. Experimental findings indicate that an optimal resin addition to a polymer matrix enhances strength and, consequently, decreases expenses. Epoxy–polymer matrices with an optimal mineral filler content of up to 30% demonstrate the highest durability. The increases in compressive and flexural strength for the matrix with 30% PC were 7.3% and 11.5%, for the matrix with 30% MS they were 4.1% and 4.4%, and the increases were 11.2% and 13.2% for the matrix with 15%PC+15%MS. Introducing a mineral filler increases the density of epoxy–polymer matrices up to 50%. Water absorption of polymer matrices increases as the amount of mineral filler in the matrix increases. The microstructure of polymer matrices with mineral fillers is dense and homogeneous, with a small number of pores. In optimal quantities, the mineral filler is evenly distributed in the polymer binder, improves the particle packing density, and creates additional stress redistribution centers. The polymer matrix of 70% epoxy resin, 15% PC and 15% MS is the most optimal in terms of the properties obtained: a density of 1282 kg/m3; compressive strength of 54.7 MPa; flexural strength of 20.6 MPa; and water absorption of 0.94%. In the future, it is planned to use this epoxy–polymer matrix composition in the development of high-performance concrete intended for manufacturing machine tool beds. Full article

(This article belongs to the Special Issue Smart and Low-Carbon Concrete Composites)

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15 pages, 1095 KB

Open AccessArticle

The Interface Stabilization Effects of Silane in SEBS/BaTiO₃ Composites—Part I—Thermal Approach

by Traian Zaharescu, Radu Mirea, Tunde Borbath and Istvan Borbath

J. Compos. Sci. 2026, 10(7), 355; https://doi.org/10.3390/jcs10070355 - 2 Jul 2026

Viewed by 746

Abstract

The contributions of BaTiO₃ as the filler and 3-glycidoxypropyltrimethoxysilane as the binder in the matrices of styrene–ethylene–butylene–styrene are evaluated for extended applications in medicine and dentistry. The determinations of stability are achieved by chemiluminescence (CL) under isothermal and nonisothermal modes, measuring the [...] Read more.

The contributions of BaTiO₃ as the filler and 3-glycidoxypropyltrimethoxysilane as the binder in the matrices of styrene–ethylene–butylene–styrene are evaluated for extended applications in medicine and dentistry. The determinations of stability are achieved by chemiluminescence (CL) under isothermal and nonisothermal modes, measuring the values of oxidation induction time (OIT) and onset oxidation temperature (OOT), respectively, which characterize the progress of material oxidation. The calculation of activation energies for the progress of oxidation from isothermal CL measurements based on OIT values provides proof of the modification of interaction activity on the polymer/barium titanate interface. The increases in the activation energy values from 80 kJ mol⁻¹ for neat polymer to 83 kJ mol⁻¹ for SEBS/BaTiO₃ 1 wt% and 109 kJ mol⁻¹ for SEBS/BaTiO₃ 1 wt%/GPTMS 1 wt% is evidence of the contribution of silane to the structuration of the polymer surface. The influence of the two compounds, filler and additive, makes possible the extension of oxidation induction temperatures measured at 170 °C from 36 min, displayed by pristine polymer, to 245 min and 278 min for the titanate composites free of silane and in the presence of GPTMS 1 wt%, respectively. Full article

(This article belongs to the Section Polymer Composites)

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30 pages, 10265 KB

Open AccessArticle

The Seismic Reduction Effect of Integrated Composite Isolation Bearings with Semi-Metallic Friction Tile Dampers

by Xiangyu Gao, Jingyu Su, Qingsong Guan, Jiuwei Wang, Chengwei Wang, Jinlai Zhou, Wenli Han and Fan Wu

J. Compos. Sci. 2026, 10(7), 354; https://doi.org/10.3390/jcs10070354 - 30 Jun 2026

Viewed by 357

Abstract

A novel two-stage friction damper (semi-metal composite material) proposed and tested in the paper, some of which can be connected in parallel with regular isolation bearing to form a new composite type combined isolation bearing. It can significantly improve the matching of isolation [...] Read more.

A novel two-stage friction damper (semi-metal composite material) proposed and tested in the paper, some of which can be connected in parallel with regular isolation bearing to form a new composite type combined isolation bearing. It can significantly improve the matching of isolation parameters under multi-level earthquakes (helping to improve the applicability and sustainability of the structure) and enhance the isolation effect. Traditional methods, such as adding lead cores to laminated rubber bearings (LNR) to obtain LRB, or adding metal dampers, viscous dampers, etc., often encounter problems such as insufficient matching of isolation parameters (such as excessive slice force under frequent earthquakes and insufficient damping ratio under rare earthquakes), or space limitations due to the addition of dampers. To address these limitations, this paper proposes this new structure and uses the theory of elasticity mechanics to establish a set of methods for calculating the internal force and deformation of the damper, which can be used for the compact design of the internal structure and connecting components of the damper. After assembly and testing, it shows the damper can ensure reliable operation with a compact size and providing satisfactory damping performance. Independent mechanical performance tests confirm the shape characteristics of the force–displacement hysteresis curve, the appropriate preload torque value, and the technical parameters under variable displacement and variable speed loading conditions. The full-scale combined isolation bearing (LNRF) test verifies the working principle of the damper and the stable bone-shaped force–displacement hysteresis curve output, and compared with LNR, the equivalent viscous damping ratio increases by −14.8% (due to the increase in stiffness), 7.1%, 20.2%, and 24.0% at shear angles of 100%, 200%, 250%, and 300%, respectively. This indicates that the new combined isolation bearing structure and damper design method proposed in this paper can assist in the design of combined bearing structures and the development of products of various specifications, and suits for application in isolation buildings, bridges, and other engineering projects. Full article

(This article belongs to the Special Issue Advanced Composite Materials and Design for Structural Safety and Sustainability)

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17 pages, 13928 KB

Open AccessArticle

Bio-Inspired Functional Freedom: Additive Manufacturing Enables Roof Handle Design

by Xueping Guo

J. Compos. Sci. 2026, 10(7), 353; https://doi.org/10.3390/jcs10070353 - 30 Jun 2026

Viewed by 347

Abstract

The integration of additive manufacturing technology and biomimetic design provides new possibilities for functional and aesthetic innovation in automotive interiors. This study explores a roof handrail design method based on a spider web biomimetic structure from the perspectives of object character and design [...] Read more.

The integration of additive manufacturing technology and biomimetic design provides new possibilities for functional and aesthetic innovation in automotive interiors. This study explores a roof handrail design method based on a spider web biomimetic structure from the perspectives of object character and design freedom. By transforming the spider web morphology of nature into a manufacturable parametric model, the organic unity of structural performance and visual aesthetics has been achieved. The simulation results show that the spider web biomimetic structure handrail distributed along the z-axis not only meets the mechanical performance (maximum stress of 189.11 MPa under 1500 N load) but also theoretically reduces weight by 32.03% compared to traditional designs. Material testing shows that the spider web biomimetic structure handrail made of PA6-CF material through fused deposition molding not only meets safety requirements but also has a better user experience. This study achieved organic forms that are difficult to process with traditional techniques through 3D printing technology, providing a new paradigm of “form following ecology” for automotive interior design and expanding the possibilities of functional components in user experience and spatial narrative. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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16 pages, 596 KB

Open AccessArticle

Application of the Transfer Function Method to Vibration Analysis of Functionally Graded Beams in Thermal Environments

by Chen Chen, Xiuxin Yang and Chuan Zeng

J. Compos. Sci. 2026, 10(7), 352; https://doi.org/10.3390/jcs10070352 - 30 Jun 2026

Viewed by 338

Abstract

Characterized by a continuous gradient in both microstructure and material properties, functionally graded materials (FGMs) are well-suited for integrated heat protection and load-bearing structures. Thermal vibration of FGMs is the basis to ensure service safety under a thermo-dynamic load environment. Current research predominantly [...] Read more.

Characterized by a continuous gradient in both microstructure and material properties, functionally graded materials (FGMs) are well-suited for integrated heat protection and load-bearing structures. Thermal vibration of FGMs is the basis to ensure service safety under a thermo-dynamic load environment. Current research predominantly relies on numerical algorithms, with a notable absence of analytical expressions for frequency characteristics. This study extends the application of the transfer function method (TFM) to the vibration of FGM beams. Firstly, the thermal vibration governing equations were derived based on Timoshenko beam theory and Hamilton’s principle. Then, the frequencies of the two types of FGM beams were calculated using the TFM. Finally, the adaptability of the TFM was validated, and the time cost was analyzed. The results indicated that the analytical transfer-function formulation and solution obtained by the TFM agree well with the Navier method and the generalized differential quadrature method, demonstrating the high applicability of the present approach. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Mechanical Analysis of Composite Materials)

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18 pages, 4773 KB

Open AccessArticle

Vertically Aligned Boron Nitride Fiber Paper Thermal Interface Materials with High Electrical Insulation for Electronics Heat Dissipation

by Zexi Chen, Yixin Chen, Xu Huang and Sheng Chu

J. Compos. Sci. 2026, 10(7), 351; https://doi.org/10.3390/jcs10070351 - 30 Jun 2026

Viewed by 481

Abstract

Effective thermal management is critical for ensuring the reliability of modern high-power electronic devices, where thermal interface materials (TIMs) play key roles in minimizing contact resistance and improving heat dissipation. Boron nitride (BN) is widely used as a thermally conductive filler due to [...] Read more.

Effective thermal management is critical for ensuring the reliability of modern high-power electronic devices, where thermal interface materials (TIMs) play key roles in minimizing contact resistance and improving heat dissipation. Boron nitride (BN) is widely used as a thermally conductive filler due to its high in-plane thermal conductivity and electrical insulation. However, achieving BN-based polymer composites that simultaneously offer high filler loading, flexibility, and high thermal conductivity (κ) remains a significant challenge. In this work, we introduce a novel two-step fabrication strategy to overcome this limitation. First, continuous BN fibers with high aspect ratios are assembled into BN fiber papers with enhanced fiber alignment. These papers are then cut and integrated into a silicone matrix to form well-oriented thermal conductive channels. This approach enables a significantly higher filler mass fraction of 70%, resulting in a thermal pad with a high κ of 19.23 W/(m·K), low thermal resistance of 1.61 cm²·K/W, and excellent electrical insulation and flexibility. Application tests further demonstrate superior heat dissipation performance and operational stability compared to commercial silicone pads. This work not only highlights the potential of BN fiber-based TIMs but also offers a feasible process for their large-scale manufacturing. Full article

(This article belongs to the Section Composites Applications)

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31 pages, 13865 KB

Open AccessArticle

Topological Optimization of Steel and Concrete Tubular-Floor Trusses Based on CO₂ Emission

by Chayana M. G. Silva, Beatriz V. Afonso, Adenílicia F. G. Calenzani, Moacir Kripka and Élcio C. Alves

J. Compos. Sci. 2026, 10(7), 350; https://doi.org/10.3390/jcs10070350 - 30 Jun 2026

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Abstract

This paper addresses the topological optimization of composite floor systems, specifically focusing on tubular composite trusses with and without concrete filling in the upper chord. The optimization problem is formulated and solved using particle swarm optimization (PSO) and the Bonobo Algorithm (BO), both [...] Read more.

This paper addresses the topological optimization of composite floor systems, specifically focusing on tubular composite trusses with and without concrete filling in the upper chord. The optimization problem is formulated and solved using particle swarm optimization (PSO) and the Bonobo Algorithm (BO), both with CO₂ emissions reduction as the objective. A comparative analysis is conducted against literature models using full-web beams, revealing a notable 20%+ reduction in total CO₂ emissions for the proposed composite truss configuration. Additionally, a parametric analysis examines how various design parameters affect the optimization solution. Results indicate that the use of concrete in the upper chord has a substantial effect on reducing overall CO₂ emissions, especially with concrete strengths exceeding 25 MPa. Notably, the Bonobo Algorithm outperforms PSO in finding optimal solutions for the composite floor system. The study contributes to the underexplored field of topological optimization for composite truss beams, providing valuable insights into sustainable design practices for structural engineering applications. Full article

(This article belongs to the Section Composites Applications)

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Open AccessArticle

Comparative Performance of Reinforced Concrete Beams Strengthened with Shape Memory Alloys and CFRP Using an Equivalent Stiffness Approach

by Jameel Taher, Mohammad Amin Molod and Ako Daraei

J. Compos. Sci. 2026, 10(7), 349; https://doi.org/10.3390/jcs10070349 - 30 Jun 2026

Cited by 1 | Viewed by 457

Abstract

The enhancement of reinforced concrete (RC) beams using externally bonded carbon fiber-reinforced polymer (CFRP) systems and shape memory alloy (SMA) systems has been growing in recent years, but its comparison is not generalizable unless it is based on an equal basis of stiffness. [...] Read more.

The enhancement of reinforced concrete (RC) beams using externally bonded carbon fiber-reinforced polymer (CFRP) systems and shape memory alloy (SMA) systems has been growing in recent years, but its comparison is not generalizable unless it is based on an equal basis of stiffness. In this paper, an equivalent axial stiffness approach is applied to study the effect of CFRP and SMA plates on RC beams. The following four beam configurations were considered: Unstrengthened control beam, beam strengthened with a 5 mm SMA plate, beam strengthened with a 5 mm CFRP plate, and beam strengthened with an 18.96 mm SMA plate, which was chosen to provide similar axial stiffness as the 5 mm CFRP plate. The finite element model was created using ANSYS and compared with experimental results from the literature, and was further validated with a mesh sensitivity study. The test results indicated that all strengthening systems had a better flexural response than the control beam, but with varying degrees of improvement depending heavily on the amount of stiffness provided by the strengthening material. The control beam showed the first signs of cracking and had the lowest resistance. The moderate improvement was seen in the 5 mm SMA plate, which increased the load corresponding to the first crack to 50.2 kN from 41.7 kN. The 5 mm CFRP beam and the stiffness-equivalent SMA 18.96 mm beam, on the other hand, were able to significantly improve the first-crack load to 77.6 kN and 82.97 kN, respectively. In terms of flexural strengthening performance, stiffness equivalence takes into account the first-crack load of the performance of the SMA beam, which shows that SMA can provide flexural strengthening performance comparable to, and even higher than, that of the CFRP system in terms of crack-initiation resistance. The overall performance of the strengthened beams was also found to be better than the control beam in terms of the post-cracking stiffness and moment—curvature relationships. These results indicate that a stiffness-equivalent framework is more rational than comparing the two strengthening systems directly in terms of thickness, and in this way, the ability to compare the advantages and disadvantages of the two systems. The conclusions, however, should be understood based on the assumptions of the numerical model, such as the perfect bond assumption at the interface and the use of a simplified monotonic material model used for SMA. Additional studies should be conducted that incorporate debonding, cyclic loading, temperature, and field size verification. Full article

(This article belongs to the Section Composites Modelling and Characterization)

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J. Compos. Sci., Volume 10, Issue 7 (July 2026) – 49 articles

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