Search Results (47)

This article provides a comprehensive review of the literature on the use of graphene-based nanomaterials (graphene oxide, reduced graphene oxide, and graphene nanoplatelets) and nanosilica (SiO₂) in architectural paint and coatings. The aim was to quantitatively assess their effect on dirt pickup resistance, hydrophobicity, and mechanical properties. In a systematic search across ScienceDirect, Scopus, and Web of Science (2010–2025), 20 studies that met the set inclusion criteria were identified. We extracted and generalized data with random-effects models (REML) based on standardized mean differences, conducting subgroup and meta-regression analyses to assess filler type, loading, and binder system impact. The results reveal that graphene-based fillers and SiO₂ improve coating performance at the same time, and hybrid graphene-SiO₂ systems may provide a synergistic improvement depending on the binder matrix. Our results present the first quantitative evidence of graphene-SiO₂ interaction in the coating formulations, identify remaining research gaps, and indicate methods for designing next-generation facade paints with better dirt repellence, durability, and sustainability. Full article

Phenolic aerogel holds great promise for applications in thermal protection against ablation, and constructing inorganic–organic hybrid networks is an effective strategy to enhance its oxidation and ablation resistance. This study introduces a stepwise hybridization strategy for the preparation of SiO₂–ZrO₂–phenolic resin aerogels (SZPA). First, nano-silica sol and nanometer-scale zirconia were physically blended to form a uniformly dispersed mixture. Subsequently, the modified silica was incorporated into a phenolic resin solution to construct a three-dimensional hybrid silica–phenolic network framework. Nano-sized zirconia was then uniformly dispersed within the matrix as a physical reinforcing phase through high-shear dispersion. Finally, the SZPA with a hierarchical nanoporous structure was obtained via ambient-pressure drying. Owing to its unique hybrid network structure, the aerogel exhibits markedly improved properties: the thermal conductivity is as low as 0.0419–0.0431 W/(m·K) (a reduction of approximately 24%), and the specific surface area is as high as 190–232 m²/g (an increase of approximately 83%). Meanwhile, the inorganic network considerably enhances the residual mass at elevated temperatures, as well as the oxidation resistance and thermal stability of the matrix. Among the tested materials, the SZPA-4 exhibited outstanding thermal insulation capability at high temperatures; its back surface temperature reached only 74.4 °C after 600 s of exposure to a 1200 °C butane flame. This study provides a feasible route for the preparation of high-performance phenolic-based composite aerogels for aerospace thermal protection systems, thereby expanding their potential applications in extreme thermal environments. Full article

Hybrid hydrophobic coatings (HHCs), which combine organic and inorganic materials, have demonstrated superior weathering resistance compared to conventional organic coatings in conserving stone heritage structures. Among the inorganic components of HHCs, nanosilica is especially promising because of its ability to form durable, weathering-resistant and hydrophobic silane-based structures. This overview examined recent studies, advances, and emerging trends about nanosilica-based HHCs from 2020 to 2024 using the “Boolean strategy” and search terms “stone”, “heritage”, “hydrophobic”, and “coating”, capturing 5244 articles. After screening for titles containing “nanosilica” (470 items remained), excluding works related to “consolidants” and “cement” (171 items remained), and requiring quantitative data on formulations, methods, and performance of nanosilica-based HHCs in stone heritage structures, 16 relevant works were identified. China and Italy dominated research works on nanosilica-based HHC development, which was applied to stone heritage structures composed of carbonate materials (e.g., limestone, dolomite, and Palazzolo carbonates) and silica-rich materials (e.g., Qingshi stone, Hedishi stone, and red sandstone). Key evaluation metrics reported by multiple authors to evaluate HHC efficacy included water contact angle (WCA), total color difference (TCD), and solution pH. Moreover, ultraviolet light (UV) durability, thermomechanical stability, biocidal efficiency, and graffiti protection were achieved when nanosilica was combined with other nanomaterials. Integrating emerging technologies, such as artificial intelligence (AI), internet-of-things (IoT), and smartphones with colorimeter apps could improve accessibility, real-time monitoring and reliability of HHC testing, while adherence to standardized testing protocols would further enhance comparability and practical application across studies. Overall, this overview provides valuable insights into nanosilica-based HHCs for researchers and restorers/conservators of stone heritage structures. Full article

This study systematically investigates the effects of individual and combined incorporation of graphene oxide (GO) and nano-silica sol (NS) on the macroscopic properties and microstructure of cement-based grouting materials, with emphasis on their synergistic mechanisms. A series of macroscopic tests including setting time, fluidity, bleeding rate, and mechanical strength were conducted, complemented by multi-scale microstructural characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and Fourier-transform infrared spectroscopy (FTIR). The results demonstrate that both NS and GO effectively reduce setting time and bleeding rate while enhancing mechanical strength; however, NS exhibits a more pronounced adverse effect on fluidity compared to GO. The hybrid system displays a distinct transition from synergy to antagonism: under low-dosage co-incorporation (2 wt% NS + 0.01 wt% GO), the flexural and compressive strengths increased by 13.5% and 45.5%, respectively, relative to the reference group. Microscopic analysis revealed that the synergistic interaction between the pozzolanic effect of NS and the templating effect of GO under this condition optimizes hydrate morphology and pore structure, leading to enhanced performance. Conversely, excessive dosage of either component induces agglomeration, resulting in microstructural deterioration and performance degradation. This study establishes optimal dosage ranges and combination principles for NS and GO in cement-based materials, providing a theoretical foundation for designing high-workability and high-strength cementitious composites. Full article

This study aims to investigate the mechanical behavior of cement mortar and concrete through a hybrid approach that integrates artificial intelligence (AI) techniques with finite element modeling (FEM). Support Vector Machine (SVM) models with Radial Basis Function (RBF) and polynomial kernels, along with Multilayer Perceptron (MLP) neural networks, were employed to predict the compressive strength (Fc) and flexural strength (Fs) of cement mortar incorporating nano-silica (NS) and micro-silica (MS). The dataset comprises 89 samples characterized by six input parameters: water-to-cement ratio (W/C), sand-to-cement ratio (S/C), nano-silica-to-cement ratio (NS/C), micro-silica-to-cement ratio (MS/C), and curing age. Simultaneously, the axial compressive behavior of C20-grade concrete was numerically simulated using the Concrete Damage Plasticity (CDP) model in ABAQUS, with stress–strain responses benchmarked against the analytical models proposed by Mander, Hognestad, and Kent–Park. Due to the inherent limitations of the finite element software, it was not possible to define material models incorporating NS and MS; therefore, the simulations were conducted using the mechanical properties of conventional concrete. The SVM-RBF model demonstrated the highest predictive accuracy with RMSE values of 0.163 (R² = 0.993) for Fs and 0.422 (R² = 0.999) for Fc, while the Mander model showed the best agreement with experimental results among the FEM approaches. The study demonstrates that both the SVM-RBF and CDP-based modeling approaches serve as robust and complementary tools for accurately predicting the mechanical performance of cementitious composites. Furthermore, this research addresses the limitations of conventional FEM in capturing the effects of NS and MS, as well as the existing gap in integrated AI-FEM frameworks for blended cement mortars. Full article

Unmanned maritime vehicles (UMVs) have become essential tools in marine research and monitoring, significantly enhancing operational efficiency and reducing risks and costs. Fiber-reinforced composites have been widely used in marine applications due to their excellent characteristics. However, environmental concerns and the pursuit of sustainable development goals have driven the development of environmentally friendly materials. The development of eco-friendly biocomposites for UMV construction can effectively reduce the environmental impact of marine equipment. This study investigates the effects of seawater aging on kenaf/flax/glass-fiber-reinforced composites under artificial seawater conditions and determines their ranking for UMVs using the Analytic Hierarchy Process (AHP). These hybrid composites, fabricated with various stacking sequences, were prepared using a combination of hand lay-up and vacuum bagging techniques. All plant fibers underwent sodium hydroxide treatment to eliminate impurities and enhance interfacial bonding, while nano-silica was incorporated into the epoxy matrix to improve overall performance. After 50 days of immersion in artificial seawater, mechanical tests were conducted to evaluate the extent of changes in mechanical properties. Subsequently, the AHP analysis was performed based on three main criteria and thirteen sub-criteria to determine the most suitable configuration for marine applications. The results demonstrate that the stacking sequence plays a critical role in resisting seawater-induced degradation and maintaining mechanical performance. GKFKG exhibited the highest retention rates for both tensile strength (86.77%) and flexural strength (88.36%). Furthermore, the global priority vector derived from the AHP analysis indicates that hybrid composites consisting of kenaf, flax, and glass fibers consistently ranked highest. The optimum configuration among these hybrid composites was determined to be GKFKG, followed by GFKFG, GKKKG, and GKGKG. Full article

In order to improve the durability performance of sticky rice–lime paste in ancient masonry restoration materials, the effect of graphene oxide–nanosilica hybrids (GO–NS) on its basic physical properties and durability performance was investigated. The surface morphology, physical phase characteristics and infrared spectra of GO–NS and its sticky rice–lime paste were analysed by SEM, FE-TEM, XRD and FTIR. It was shown that NS successfully attached to the GO surface and improved the interlayer structure of GO. GO–NS reduces the fluidity and shrinkage of sticky rice–lime paste, prolongs the initial setting, shortens the final setting and significantly improves the compressive strength, water resistance and freeze resistance. As NS improves the interlayer structure of GO, it provides nucleation sites for the hardening of the sticky rice–lime paste, improves the quantity and structural distribution of the hardening products and reduces the pores. The NS undergoes a hydration reaction with Ca(OH)₂ in the lime to produce calcium silicate hydrate (C–S–H), which further refines the internal pore structure of the sticky rice–lime paste. As a result, the GO–NS-modified sticky rice–lime paste has a denser interior and better macroscopic properties. Full article

Lightweight concrete (LWC) has emerged as a transformative material in sustainable and high-performance construction, driven by innovations in engineered lightweight aggregates, supplementary cementitious materials (SCMs), fiber reinforcements, and geopolymer binders. These advancements have enabled LWC to achieve compressive strengths surpassing 100 MPa while reducing density by up to 30% compared to conventional concrete. Fiber incorporation enhances flexural strength and fracture toughness by 20–40%, concurrently mitigating brittleness and improving ductility. The synergistic interaction between SCMs and lightweight aggregates optimizes matrix densification and interfacial transition zones, curtailing shrinkage and bolstering durability against chemical and environmental aggressors. Integration of recycled and bio-based aggregates substantially diminishes the embodied carbon footprint by approximately 40%—aligning LWC with circular economy principles. Nanomaterials such as nano-silica and carbon nanotubes augment early-age strength development by 25% and refine microstructural integrity. Thermal performance is markedly enhanced through advanced lightweight fillers, including expanded polystyrene and aerogels, achieving up to a 50% reduction in thermal conductivity, thereby facilitating energy-efficient building envelopes. Although challenges persist in cost and workability, the convergence of hybrid fiber systems, optimized mix designs, and sophisticated multi-scale modeling is expanding the applicability of LWC across demanding structural, marine, and prefabricated contexts. In essence, LWC’s holistic development embodies a paradigm shift toward resilient, low-carbon infrastructure, cementing its role as a pivotal material in the evolution of next-generation sustainable construction. Full article

Anti-washout admixtures (AWAs) are a unique component of underwater non-dispersive concrete (UNDC), which gives the concrete the ability to remain undispersed in water. On some special occasions, freshly mixed underwater non-dispersive concrete is exposed to the erosion of moving water, and conventional acrylamide-based AWAs are only suitable for static water or the water flow rate is small. In this study, the inorganic component nanosilica (NS) is modified, treated, and copolymerized with the organic components acrylamide (AM) and acrylic acid (AA) to form an inorganic–organic hybrid polymer with a hyperbranched structure, which changes the linear structure of the original polyacrylamide molecule, and we optimize the synthesis process. The polymers are characterized at the microscopic level and their compatibility with polycarboxylic acid water-reducing agents (SP) is investigated. In addition, the polymers are compared and evaluated with commonly used PAM in terms of their working performance. The experimental results indicated that under specific process conditions, polymers endow cement mortar with good resistance to water erosion. At the same time, the polymers’ three-dimensional network structure is prominent, with good compatibility with SP and better anti-dispersity. The microstructure of the cement paste with added polymers is dense and flat, but its flowability and setting time are slightly worse. This study provides a new development direction for the development of AWAs under a dynamic water environment, which has specific engineering significance. Full article

This study evaluated the effects of print orientation and thermal aging on the flexural strength (FS) and flexural modulus (FM) of novel permanent three-dimensional (3D)-printed polymethyl methacrylate (PMMA) resins reinforced with nano-zirconia and nano-silica. Bar-shaped specimens (25 × 2 × 2 mm) were fabricated using a digital light processing (DLP) 3D printer (Asiga Max UV, Asiga Inc., Australia) in two orientations (0° and 90°). Specimens underwent three-point bending tests at 24 h and after artificial thermal aging (10,000 and 30,000 cycles) to simulate one and three years of intraoral conditions. Scanning electron microscopy (SEM) was used to analyze fracture patterns. Print orientation did not significantly affect FS or FM (p > 0.05). However, artificial aging significantly reduced FS and FM after 10,000 cycles (p < 0.001), with further deterioration after 30,000 cycles. The micro hybrid resin composite exhibited higher FS than the 3D-printed materials throughout aging. SEM analysis revealed distinct fracture patterns, with 3D-printed resins displaying radial fractures and the micro hybrid composite exhibiting horizontal fractures. These findings indicate that aging plays a more critical role in the long-term mechanical performance of 3D-printed restorative resins than print orientation. This study provides original data on the effects of print orientation and prolonged thermal aging on the mechanical behavior of permanent three-dimensional (3D)-printed dental resins. Furthermore, the comparative evaluation of aging protocols simulating one and three years of intraoral service represents a novel contribution to the existing literature. Further studies are required to optimize the mechanical durability of 3D-printed dental restorations. Full article

Wear resistance is the key factor that affects the long-term use of leather. Graphene has excellent wear resistance properties, but ensuring the effective dispersion of graphene in resin is crucial for determining the performance of the material. In this work, silica modified with polydopamine (SiO₂@PDA) was used as an exfoliation agent. Using the microfluidization process and water as the medium, silica-graphene hybrid nanoparticles (SiO₂@PDA-G) were prepared from expanded graphite. These nanoparticles were further compounded with waterborne polyurethane (WPU), and a superfine fiber-based fabric was used as the substrate to prepare composite coating. The results showed that the high shear force of the microfluidization process easily broke up the lamellar structure of graphite, resulting in few-layer graphene. Nano-silica was adsorbed on the surface of graphene, preventing re-aggregation between the graphene sheets. Compared to the WPU coating, the presence of SiO₂@PDA-G improved the wear resistance and mechanical properties of the coating. The wear rate and the average friction coefficient of the composite coating decreased by 48% and 69%, respectively, and the tensile strength increased by 83%. Therefore, this study provides a new strategy for improving the dispersion of graphene in polymer materials and enhancing the abrasion resistance of the coatings. Full article

This study explores the combined effects of nanosilica (NS) and basalt fibers (BF) on the mechanical and microstructural properties of superabsorbent polymer (SAP)-modified concrete. NS (0–1.5% replaced by cement weight) and BF (0–1.2% by volume fraction) were incorporated to optimize compressive, flexural, and split-tensile strengths using response surface methodology. Digital Image Correlation (DIC) was employed to analyze failure mechanisms. Results show that while SAP alone reduced strength, the addition of NS and BF mitigated this loss through synergistic microstructure enhancement and crack-bridging reinforcement. The optimal mix (0.9% NS and 1.2% BF) increased compressive, flexural, and split-tensile strengths by 15.3%, 10.0%, and 14.0%, respectively. SEM analysis revealed that NS filled SAP-induced pores, while BF limited crack propagation, contributing to improved mechanical strength of SAP-modified concrete. This hybrid approach offers a promising solution for durable and sustainable concrete pavements. Full article

This study presents the feasibility of improving some selected mechanical strengths and the inner-structural analyses of cement matrix by electrospun nanofibers containing nylon 66, nanosilica, and carbon nanotube. The hybrid electrospun nanofibers were fabricated and mixed into ordinary Portland cement. From the mechanical strength test results, the hybrid nanofibers have shown their role in improving the tensile, compressive, and toughness behavior of the mixed cement material. The improvements of 62%, 38%, and 69%, respectively, were observed compared to those of the control paste. The novelty of the surface and inner structure of the hybrid fibers, as well as the modified cement matrix, were observed by the scanned images from electron microscopes. Besides, the additional pozzolanic reaction between the generated calcium hydroxide and the attached silica was clarified thanks to the results of energy dispersive spectroscopy, X-ray diffraction, and thermal gravimetric analysis. Finally, the consistency between mechanical strength results and inner-structure analyses showed the potential of the proposed fiber to improve cement-based materials. Full article

Fiber-reinforced nano-silica concrete (FrRNSC) was applied to a concrete sculpture to address the issue of brittle fracture, and the primary objective of this study was to explore the potential of hybridizing the Grey Wolf Optimizer (GWO) with four robust and intelligent ensemble learning techniques, namely XGBoost, LightGBM, AdaBoost, and CatBoost, to anticipate the compressive strength of fiber-reinforced nano-silica concrete (FrRNSC) for sculptural elements. The optimization of hyperparameters for these techniques was performed using the GWO metaheuristic algorithm, enhancing accuracy through the creation of four hybrid ensemble learning models: GWO-XGBoost, GWO-LightGBM, GWO-AdaBoost, and GWO-CatBoost. A comparative analysis was conducted between the results obtained from these hybrid models and their conventional counterparts. The evaluation of these models is based on five key indices: R², RMSE, VAF, MAE, and bias, addressing an objective assessment of the predictive models’ performance and capabilities. The outcomes reveal that GWO-XGBoost, exhibiting R² values of (0.971 and 0.978) for the train and test stages, respectively, emerges as the best predictive model for estimating the compressive strength of fiber-reinforced nano-silica concrete (FrRNSC) compared to other models. Consequently, the proposed GWO-XGBoost algorithm proves to be an efficient tool for anticipating CSFrRNSC. Full article

The incorporation of rare earth oxides and nano-silica has been found to significantly enhance the mechanical and tribological characteristics of phenolic-based hybrid nanocomposites. In this work, the impact of these additives was investigated through single-factor experiments. The study revealed that cerium oxide and yttrium oxide were the primary factors influencing changes in the impact strength, shear strength, coefficient of friction, and wear rate. Additionally, the content of nano-silica exerted the most substantial influence on the hardness and compressive strength of the specimens. Furthermore, the material ratios of the phenolic-based hybrid nanocomposites were optimized using an orthogonal experimental design and a fuzzy comprehensive evaluation method. The optimal material ratio for these nanocomposites was determined to be 2% cerium oxide, 2.5% yttrium oxide, and 3% nano-silica, based on their mechanical, frictional, and wear properties. This research provides valuable insights for the development of new brake friction materials with low friction and high wear resistance and contributes to meeting the demand for polymer composites with superior mechanical performance in diverse applications. Full article