Search Results (242)

In this study, an effective strengthening method was investigated to improve the seismic performance of masonry brick walls. The strengthening method comprised the use of shotcrete, which was applied in both glass fiber-reinforced and unreinforced forms for steel plates and tie rods. Thirteen wall specimens constructed with vertical perforated masonry block bricks were tested under diagonal compression in accordance with ASTM E519 (2010). Reinforcement plates with different thicknesses (1.5 mm, 2 mm, and 3 mm) were anchored using 6 mm diameter tie rods. A specially designed steel frame and an experimental loading program with controlled deformation increments were employed to simulate the effects of reinforced concrete beam frame system on walls under the effect of diagonal loads caused by seismic loads. In addition, numerical simulations were conducted using three-dimensional finite element models in Abaqus Explicit software to validate the experimental results. The findings demonstrated that increasing the number of tie rods enhanced the shear strength and overall behavior of the walls. Steel plates effectively absorbed tensile stresses and limited crack propagation, while the fiber reinforcement in the shotcrete further improved wall strength and ductility. Overall, the proposed strengthening techniques provided significant improvements in the seismic resistance and energy absorption capacity of masonry walls, offering practical and reliable solutions to enhance the safety and durability of existing masonry structures. Full article

To study the influence of curing agent structure on the properties of epoxy resin, four types of aromatic diamines with the structure of diphenyl methane (4,4′-methylenedianiline (MDA), 4,4′-methylenebis(2-ethylaniline) (MOEA), 4,4′-methylenebis(2-chloroaniline) (MOCA), and 4,4′-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA)) and a high-performance epoxy resin, 3-(oxiran-2-ylmethoxy)-N,N-bis(oxiran-2-ylmethyl)aniline (AFG-90MH), were used in this study. The resulting resin systems were designated as AFG-90MH-MDA, AFG-90MH-MOEA, AFG-90MH-MOCA, and AFG-90MH-MCDEA. After curing, these systems were named AFG-90MH-MDA-C, AFG-90MH-MOEA-C, AFG-90MH-MOCA-C, and AFG-90MH-MCDEA-C. The influence of the structure of the diamines on the processability, curing reaction activity, and thermal and mechanical properties (including flexural and tensile properties) of the epoxy resins were investigated. These systems demonstrate excellent processability with wide processing windows ranging from 30 °C to 110–160 °C while maintaining low viscosity. Consistent apparent activation energy (E_a) trends via both Kissinger and Flynn-Wall-Ozawa methods were observed. The epoxy systems exhibit the following increasing E_a sequence: AFG-90MH-MDA < AFG-90MH-MOEA < AFG-90MH-MOCA < AFG-90MH-MCDEA. The processability and curing reaction kinetic results indicate that the reactivities of the diamines decrease in the order: MDA > MOEA > MOCA > MCDEA. Polar chlorine substituents in diamines strengthen intermolecular interactions, thereby enhancing mechanical performance. The flexural strength of cured epoxy systems decreases as follows with corresponding values: AFG-90MH-MOCA-C (165 MPa) > AFG-90MH-MDA-C (158 MPa) > AFG-90MH-MCDEA-C (148 MPa) > AFG-90MH-MOEA-C (136 MPa). Diamines with substituents like chlorine or ethyl groups reduce the glass transition temperatures (T_g) of the cured resin systems. However, the cured resin systems with the diamines containing chlorine demonstrate superior thermal performance compared to those with ethyl groups. The cured epoxy systems exhibit the following descending glass transition temperature order with corresponding values: AFG-90MH-MDA-C (213 °C) > AFG-90MH-MOCA-C (190 °C) > AFG-90MH-MCDEA-C (183 °C) > AFG-90MH-MOEA-C (172 °C). Full article

Chemically strengthened glass is widely used for its remarkable fracture strength, mechanical performance, and scratch resistance. Assessing its hardness is crucial to evaluating improvements from chemical tempering. However, conventional methods like Vickers hardness tests are destructive, altering the sample surface. This study presents a novel, rapid, and nondestructive testing (NDT) approach by correlating the nonlinear refractive index (n₂) with surface hardness. Using ultrafast laser pulses, we measured the n₂ cross-section via the nonlinear ellipse rotation (NER) signal in Gorilla^®-type glass subjected to ion exchange (Na⁺ by K⁺). A microscope objective lens provided a penetration resolution of ≈5.5 μm, enabling a localized NER signal analysis. We demonstrate a correlation between the NER signal and hardness, offering a promising pathway for advanced, noninvasive characterization. This approach provides a reliable alternative to traditional destructive techniques, with potential applications in industrial quality control and material science research. Full article

This study investigates the effectiveness of strain-hardening cementitious composites (SHCC) reinforced with glass fiber (GF) mesh in enhancing the torsional behavior of reinforced concrete (RC) beams with circular openings. Eight full-scale RC beams were tested under pure torsion, including two control beams and six strengthened beams with varying configurations of horizontal, vertical, and combined SHCC-GF mesh retrofitting. The experimental program evaluated the influence of single- and double-layer GF mesh reinforcement on torsional capacity, crack propagation, stiffness, and energy absorption. The results demonstrated that the presence of an opening reduced the ultimate torsional capacity by 29%, elastic stiffness by 48%, and energy absorption by 64% compared to the solid control beam. Strengthening with horizontal SHCC strips restored 21–35% of the lost capacity, while vertical strips performed even better, achieving 44–61% improvement. The combined horizontal–vertical configuration with a double-layer GF mesh proved the most effective, increasing ultimate load by 91% compared to the unstrengthened beam with an opening. Finite element models (FEM) are developed using ABAQUS to simulate the performance of the tested beams. Full article

This study presents a comprehensive review of various advanced methodologies that have been used to enhance the structural and thermal performance of masonry walls through innovative and sustainable retrofitting/upgrading techniques. Focusing on three primary approaches—mechanical/structural retrofitting, thermal retrofitting, and integrated (structural and thermal) retrofitting, this paper critically examines various masonry-strengthening strategies. Retrofitting techniques are categorized by material use and objectives. Fiber-based solutions include insulation materials, fiber composite mortar for strength, FRP for high-strength reinforcement, and TRM for durability. According to the relevant objectives, retrofitting can enhance structural stability (FRP, TRM), improve thermal insulation, or combine both for integrated performance. Particular emphasis is placed on the effectiveness of TRM systems, with a comparative analysis of man-made (glass, steel textile) and natural fiber-based TRM solutions. Regarding integrating natural fibers into TRM systems, this study highlights their potential as eco-friendly alternatives that reduce environmental impact while maintaining or improving structural integrity. Furthermore, it highlights and examines techniques for testing masonry walls. In this context, this review highlights the applicability of natural fiber as a sustainable building material in various retrofitting/upgrading solutions. Full article

The optimization of business processes is essential for enhancing efficiency and competitiveness in today’s dynamic industrial environment. This study presents a novel approach that integrates Artificial Intelligence (AI) with Failure Mode and Effects Analysis (FMEA) to automate risk assessment and enable predictive maintenance. Using real-world data from a glass manufacturing company (SK), we implemented machine learning models—Random Forest and XGBoost—to predict Risk Priority Number (RPN) values and classify failure risks. The Random Forest Regressor achieved an Coeficient of Determination (R²) of 0.999, Mean Absolute Error (MAE) of 2.18, and Root Mean Square Error (RMSE) of 2.65, indicating high accuracy in risk prediction. The Random Forest Classifier reached a classification accuracy of 82.9%, with strong recall (92.4%) for high-risk cases, making it practical for industrial deployment. The proposed AI-enhanced FMEA system supports dynamic risk management, reduces downtime, and improves maintenance planning. Our findings demonstrate that AI can significantly strengthen traditional FMEA practices and serve as a foundation for intelligent, data-driven decision-making in industrial environments. Full article

The recent fast advances in consumer electronics, especially in cell phones and displays, have led to the development of ultra-thin, hence flexible, glasses. Once available, such flexible glasses have proven to be of great interest and usefulness in other fields, too. Flexible photonics, for instance, has quickly taken advantage of this new material. At first sight, “flexible glass” appears to be an oxymoron. Glass is, by definition, fragile and highly breakable; its structure has puzzled scientists for decades, but it is evident that in most conditions it is a rigid material, so how can it bend? This possibility, however, has aroused the interest of artists and craftsmen since ancient times; thus, in Roman times the myth of flexible glass was born. Furthermore, the myth appeared again in the Middle Age, connected to a religious miracle. Today, however, flexible glass is no more a myth but a reality due to the fact that current technology permits us to produce micron-thick glass sheets, and any ultra-thin material can be bent. Flexibility is coming from the present capability to manufacture glass sheets at a tens of microns thickness coupled with the development of strengthening methods; it is also worth highlighting that, on the micrometric and nanometric scales, silicate glass presents plastic behavior. The most significant application area of flexible glass is consumer electronics, for the displays of smartphones and tablets, and for wearables, where flexibility and durability are crucial. Automotive and medical sectors are also gaining importance. A very relevant field, both for the market and the technological progress, is solar photovoltaics; mechanical flexibility and lightweight have allowed solar cells to evolve toward devices that possess the advantages of conformability, bendability, wearability, and moldability. The mature roll-to-roll manufacturing technology also allows for high-performance devices at a low cost. Here, a brief overview of the history of flexible glass and some examples of its application in solar photovoltaics are presented. Full article

This study investigates the use of Ultra-High Molecular Weight Polyethylene (UHMWPE) fibers and fabric to enhance the flexural performance of Ultra-High-Performance Concrete (UHPC). A total of 45 specimens were tested to examine the effects of fiber type, fabric material, adhesive, and various combined strengthening techniques. The main findings are that incorporating UHMWPE fiber into the ultra-high-strength mortar (HSM) matrix provides superior performance compared to steel fiber, particularly in enhancing crack resistance and energy absorption. UHMWPE fiber-reinforced UHPC achieved a flexural toughness of 307 KJ/m³, over three times higher than that of steel fiber-reinforced UHPC (98 KJ/m³). The use of UHMWPE fabrics was more effective in improving the ductility and toughness of the composites than the use of glass fabrics. The bonding effect of using epoxy resin with UHMWPE fabric is better than using magnesium phosphate cement (MPC). Increasing the number of fabric layers improved the flexural properties of externally bonded fabric but had no impact on internal reinforcement techniques. The best strengthening method in this study was a combination of incorporating UHMWPE fiber internally and externally bonded fabric on a concrete surface, yielding the highest toughness of 580 KJ/m³. Full article

This study investigates the development of sustainable polymer composites for structural strengthening by incorporating waste glass fibers and natural fibers (flax and hemp) into an epoxy matrix, in response to the growing environmental concerns. Mechanical, thermal, and durability-related properties were evaluated through tensile testing, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), water absorption, and water immersion aging tests. Results showed that incorporating waste glass fibers enhanced the tensile strength and thermal decomposition temperature by 88% and 5.4%, respectively, compared to composites reinforced with solely natural fibers. Water absorption tests indicated that waste glass fiber-reinforced hybrid composites exhibited lower water uptake than flax and hemp fiber-reinforced composites. After water immersion, the tensile strength loss was recorded as 22, 25, and 8.5% for the composites reinforced with hemp, flax, and waste glass fiber, respectively. The findings confirm that incorporating waste glass fibers into natural fiber composites effectively mitigates moisture sensitivity and improves mechanical performance. Hybridizing flax and hemp fibers with waste glass fibers provides a practical and sustainable approach to enhancing composite performance, making them a viable alternative for strengthening reinforced concrete structures requiring long-term resistance. The recycled waste glass fibers employed in this study offered comparable mechanical performance while drastically lowering raw material consumption and environmental impact, in contrast to virgin glass fibers frequently used in earlier investigations. This demonstrates how recycling-oriented composite design can provide both sustainability and performance benefits. Full article

Fabric-reinforced hybrid polymer composites are present in almost every sector of modern life, and most essential areas of research in recent years have focused on glass–carbon fabric with filler material composites. Fabric and fillers are employed in strengthening polymer composites with the aim of improving their mechanical and tribological properties. The primary objective of this investigation was to investigate thetribological and mechanical properties of unfilled and cenosphere-filled carbon–glass-reinforced polyester composite systems, utilizing two types of fabric (glass and carbon) with cenosphere filler in varying weight fractions (0, 2.5, 5, 7.5, 10, and 12.5 wt.%) for both carbon fabric and the cenosphere. The abrasive wear characteristics were evaluated using a stainlesssteel wheel abrasion tester, utilizing silica sand as the abrasive material. Tests were performed at various distances (360–1800 m) and loads (12 N and 24 N). The results show that the wear rate of carbon–glass fabric-reinforced polyester composites differs significantly, with and without cenosphere fillers. Notably, the unfilled composites exhibit the highest wear volume loss, indicating a substantial improvement in wear resistance with the addition of cenospheres. The results reveal that in carbon–glass fabric-reinforced polyester composites, specific wear rate decreases when more cenospheres are loaded. The wear rate was successfully reduced by cenospheresunder silica sand as an abrasive. Compared to unfilled composites, the mechanical properties of filled composites exhibit superior performance. These variations were explained by examining the worn-out surfaces under an SEM and correlating the features observed with the mechanical properties. Full article

This study evaluates the performance of lightweight aggregate deep beams strengthened with low-cost glass fiber-reinforced polymer composite (Lo-G) wraps as an alternative to expensive synthetic fiber-reinforced polymers (FRPs). The investigation includes side-bonded and fully wrapped configurations of Lo-G wraps, alongside carbon FRP (CFRP) strips for comparison. The experimental results show that epoxy-based anchors provided significantly better resistance against de-bonding than mechanical anchors, improving beam performance. Strengthening with Lo-G wraps resulted in a peak capacity increase of 17.0% to 46.9% for side-bonded beams in Group 2, 10.5% to 41.4% for fully wrapped beams in the strip configuration in Group 3, and 15.4% to 42.7% for CFRP strips in Group 4. The ultimate deflection and dissipated energy were also improved, with dissipated energy increases of up to 264.6%, 322.3%, and 222.7% for side-bonded and fully wrapped Lo-G wraps and CFRP strips, respectively. The side-bonded configuration with two or three Lo-G wraps, supplemented by epoxy wraps, outperformed fully wrapped 250 mm strips in peak capacity, with peak capacity improvements of up to 46.9%. However, beams with mechanical anchors showed poor performance due to premature debonding. They rely on friction and expansion within the concrete to resist pull-out forces. If the surrounding concrete is not strong enough or if the anchor is not properly installed, it can lead to failure. Additionally, reducing strip spacing negatively impacted performance. Lo-G wraps showed an 8.5% higher peak capacity and 32.8% greater dissipated energy compared to CFRP strips. Despite these improvements, while Lo-G wraps are a cost-effective alternative, their long-term performance remains to be investigated. None of the existing models accurately predicted the shear strength contribution of Lo-G wraps, as the lower elastic modulus and tensile strength led to high deviations in prediction-to-experimental ratios, underscoring the need for new models to assess shear strength. Full article

Epoxy asphalt, as a thermosetting and thermoplastic polymer composite material, has been widely used for steel bridge decks and specialty pavements due to its road performance, thermal stability, rutting resistance, and durability. However, the poor compatibility between epoxy resin binder and asphalt, due to the difference in chemical structure, polarity, and solubleness, severely restricts their practical applications in the construction of bridges and roads. Herein, we proposed a facial method to strengthen their compatibility by blending the poly(styrene-butadiene-styrene)-modified carbon nanotubes (SBS-CNTs) in the composite. The SBS-CNTs were found to evenly disperse in epoxy asphalt matrix with the epoxy resin contents of 10%–30% and could form the three-dimensional bi-continuous cross-linked structure at 30%. Moreover, the addition of epoxy resin increased the glass transition temperature (Tg) and enhanced the high-temperature shear capacity and tensile strength (over an order of magnitudes) of SBS-CNT-modified asphalt, which showed high potential for applications in the construction of bridges and roads, providing an alternative approach for improving the performance of epoxy asphalt. Full article

The detection of mirrors and glass, which possess unique optical surface properties, has garnered significant attention in recent years. Due to their reflective and transparent nature, these surfaces are often difficult to distinguish from their surrounding environments, posing substantial challenges even for advanced deep learning models tasked with performing such detection. Current research primarily relies on complex network models that learn and fuse different modalities of images, such as RGB, depth, and thermal, to achieve mirror and glass detection. However, these approaches often overlook the inherent limitations in the raw data caused by sensor deficiencies when facing mirrors and glass surfaces. To address this issue, we applied mathematical and physical methods, such as three-point plane determination and steady-state heat conduction in two-dimensional planes, along with an RGB enhancement module, to reconstruct RGB, depth, and thermal data for mirrors and glass in two publicly available datasets: an RGB-D mirror detection dataset and an RGB-T glass detection dataset. Additionally, we synthesized four enhanced and ideal datasets. Furthermore, we propose a double weight Mamba fusion network (DWMFNet) that strengthens the model’s global perception of image information by extracting low-level clue weights and high-level contextual weights from the input data using the prior fusion feature extraction module (PFFE) and the deep fusion feature guidance module (DFFG). This is complemented by the Mamba module, which efficiently captures long-range dependencies, facilitating information complementarity between multi-modal features. Extensive experiments demonstrate that our data enhancement method significantly improves the model’s capability in detecting mirrors and glass surfaces. Full article

Geopolymer concrete reinforced with MiniBars™ could be an eco-friendly, innovative, durable, high-strength material substitute for common Portland cement in buildings. AR glass fiber MiniBars™ composites (AR MiniBars™) (ReforceTech AS, Royken, Norway) 60 mm in length were utilized to strengthen the geopolymer matrix for the fabrication of unidirectional geopolymer composites reinforced by AR MiniBars™ (AR MiniBars™ FRBCs). New AR MiniBars™ FRBCs were fabricated by adding different amounts of AR MiniBars™ (0, 12.5, 25, 50, 75 vol.%) into the fly ash geopolymer paste. Geopolymers were obtained by combining fly ash powder with Na₂SiO₃/NaOH in a ratio of 2.5:1, which served as an alkaline activator. AR MiniBars™ FRBCs were cured for 48 h at 70 °C and tested for different mechanical properties. Fly ash, AR MiniBars™, and AR MiniBars™ FRBC were evaluated by optical microscopy and SEM. The addition of AR MiniBars™ increased the mechanical properties of AR MiniBars™ FRBCs. The mechanical properties of AR MiniBars™ FRBCs were heightened compared to the geopolymer without AR MiniBars™; the flexural strength was 18.80–30.71 times greater, the flexural modulus 4.07–5.25 times greater, the tensile strength 3.49–8.27 times greater, the force load at upper yield tensile strength 3.6–7.72 times greater, and the compressive strength for cubic samples 2.75–3.61 times greater. The fractured surfaces and sections of AR MiniBars™ FRBCs were inspected by SEM and optical microscopy analyses, and even though there was no chemical adhesion, we achieved a good micromechanical adhesion of the geopolymer to AR MiniBars™. These results obtained encouraged us to propose AR MiniBars™ FRBCs for application in construction. Full article

In this study, unreinforced masonry (URM) walls constructed from concrete blocks and clay bricks were strengthened using horizontally and vertically oriented glass fiber-reinforced polymer (GFRP) grid strips bonded with sprayed polyurea. The walls were subjected to diagonal compression loading until failure. The results demonstrated a significant improvement in both the shear capacity and pseudo-ductility of the strengthened URM walls compared to their unstrengthened counterparts. The primary conclusions drawn from this research are as follows: (1) the maximum strain in the vertical GFRP strips increased with the higher axial stiffness of the strips; (2) the discrete vertical strips contributed substantially to enhancing the shear capacity and pseudo-ductility of the URM walls; (3) increasing the axial stiffness of the vertical strips can alter the failure mode of the walls, shifting it from joint failure to tension or compression failure of the blocks or bricks; (4) a reduction factor is necessary to account for the potential asymmetrical performance of double-sided strengthening schemes applied to URM walls. The experimental program was reported in a previous publication and additional information is presented in this paper. Full article