Papers by Keyword: Flexural Strength

Abstract: The present study evaluated the mechanical behavior of adobe when incorporating crushed barley straw as a natural stabilizer. Specimens were prepared with three different stabilizer proportions: 0, 1, and 2%. These were used to compare their compressive and flexural strength. The results showed an average 10% increase in compressive strength and a 43% increase in flexural strength in adobes incorporating 2% stabilizer compared to the control units. This increase demonstrates the potential of crushed barley straw to improve the load-bearing capacity and ductility of adobe, thus contributing to the creation of sustainable material for construction in rural areas.

Abstract: Rapid urbanization, economic expansion and population growth have led to a significant increase in global solid waste production, which threatens ecosystems, depletes natural resources, and negatively affects human health. Textile waste has reached 150 million tons per year and constitutes a significant portion of this growing waste stream. At this point, interest in the use of recycled materials as an alternative raw material has increased, and composite materials have emerged as a promising area for the evaluation of textile waste, offering sustainable solutions for resource recovery and waste management. In this study, hybrid composites are developed by introducing various fibrous waste groups (denim and human hair) and bio-resin (acrylated epoxidized soybean oil, AESO) to E-glass reinforced epoxy composites, and the effects of waste type and bio-resin addition on the flexural strengths of the structures are examined using a full factorial experimental design. In this regard, three different sandwich structures are designed, with the outer layers made of E-glass woven fabric and the middle layers made of either E-glass fabric for control samples or different waste groups, and the productions are carried out using the vacuum infusion method. Pure epoxy or an epoxy system with 30% AESO additive is used as matrix material. Statistical results indicate that reinforcement type has a huge effect on the flexural properties individually and in binary interactions of of other factors. The performance results show that the flexural strength is improved with addition of waste regardless of their type and the best flexural properties are seen in samples with denim waste reinforcement containing cotton fiber, while the addition of AESO appears to have a negative effect. The composite structures developed within this study have the potential to replace particle boards, thus contributing to solid waste management and producing innovative solutions to resource scarcity.

Abstract: The Philippines is facing environmental challenges due to the increasing plastic waste and crop residues. To address this issue and enhance the country's economy while ensuring sustainability, research and the effective development of waste utilization strategies are paramount. This study focuses on the fabrication, characterization, and testing of fiber-polymer composites using corn cob pith particles and recycled polypropylene. Corn cob pith particles (CCP) at varying filler loadings (5, 10, and 15 wt.%), recycled polypropylene (RPP), and maleic anhydride grafted polypropylene (MAPP) were combined using a single screw extruder. As a result, the incorporation of CCP particles demonstrated a significant increase in flexural strength, flexural modulus, and tensile modulus with highest values reaching 21.88 MPa, 437.19 MPa, and 239.61 MPa, respectively. The significant increase in flexural strength and flexural modulus was observed at 10% loading, for tensile modulus it was at 15% loading. On the other hand, tensile decreased with the lowest value of 19.24 MPa at 15% loading. Moreover, the composites exhibited better thermal stability than RPP. Furthermore, the FTIR peaks located at1033 cm⁻¹ and 3340 cm⁻¹ confirm the incorporation of CCP particles into the RPP matrix. Overall, adding CCP particles to RPP, using a compatibilizer, enhanced the stiffness and rigidity of the composite, as well as its fiber-polymer adhesion. Industries can utilize the composite in applications requiring stiffness and rigidity.

Abstract: The increasing need for eco-friendly building materials has led to research into using natural fibres as reinforcement in concrete structures. This study investigates the flexural strength of kenaf fibre-reinforced concrete (KFRC) beams using both experimental and numerical analysis. Kenaf fibres are known for their excellent tensile strength and environmental friendliness. Four beam samples (A, B, C, and D) were tested. The samples had 100mm (control), 125 mm, 150 mm, and 175 mm shear spacing, respectively. Kenaf fibre was added to samples B, C, and D to determine its effect on flexural performance at an optimal content and length. The three-point bending test was conducted to evaluate key parameters such as flexural strength and deflection. Additionally, the imaging characterisation of kenaf fibre reinforced concrete and plain concrete using micro-and nanoparticles was examined and analysed using scanning electron microscopy. A finite element model was developed using Abaqus software to simulate the flexural behaviour of KFRC beams and validate the experimental results. The beam Samples A, B, C, and D have the flexural strength of 62 MPa, 72 MPa, 68 MPa, and 55 MPa, respectively and deflection values of 23.08 mm, 19.03 mm, 21.85 mm, and 31.25 mm, respectively. When comparing the flexural strength of samples B and C to that of the control sample, the results showed that the flexural strength rose by 10% and 4.6%, respectively. The flexural strength and deflection numerical models are 94% and 90%, respectively. The efficiency of the suggested model was confirmed by the numerical simulations, which demonstrated good agreement with experimental results. The potential of kenaf fibre as a workable substitute for shear reinforcement in environmentally friendly concrete constructions is highlighted by this study.

Abstract: This study investigates the effect of different joint designs and surface treatments on the flexural strength of a 3D-printed resin denture base. Seventy specimens of 3D-printed resin were used in this study, these specimens were grouped according to the joint design into four groups (positive control group, butt-joint group, bevel-joint group, and round-joint group) except the positive control group each one of these groups is subgroup into another three groups according to the surface treatment material into heat-cured monomer (MMA), sandblast, and 3-D printed resin. The specimens were cut in the middle according to the joint shape, and the cut surfaces were treated with heat-cured MMA monomer, sandblast, and 3D-printed resin (as a negative control group). Then a silicone mold was used to prepare the specimens with 3D printed resin, using a light-emitting diode, and post-cured with a light-cured unit box. An Instron testing machine examines all specimens. The bevel-joint group repaired with 3D printed resin (G7) had the highest mean flexural strength (85.0483) MPa and a significant difference from the control group. For fixing a fractured denture base made of 3D-printed resin, the bevel-joint design is the most recommended design of the joint, and the best material for treatment is 3D-printed resin. Then a round-joint with heat-cured monomer and the butt-joint with 3D-printed resin treatment.

Abstract: Natural fibre composites are gaining importance in engineering and automotive sectors due to their sustainability, lightweight nature, and cost-effectiveness. However, their flexural modulus and other mechanical properties require enhancement to meet industrial standards. This study aims to improve the performance of hybrid composites reinforced with hemp, jute, and coir fibres in an epoxy matrix. Specimens were fabricated using the hand lay-up technique followed by compression moulding and tested according to ASTM standards. Mechanical characterization included hardness, tensile, flexural, compressive, and impact tests, along with water absorption analysis. The results demonstrated significant improvements, with maximum hardness of 80 HRM, tensile strength of 16.95 N/mm², compressive strength of 5.268 N/mm², flexural strength of 95.96 N/mm², and impact resistance of 0.20 J. Water absorption varied between 11.6% and 25%, depending on resin-to-fibre ratios. One-way ANOVA confirmed statistically significant differences among formulations (p = 0.005), validating the effect of fibre–resin composition. The optimal formulation (75% epoxy with balanced fibre reinforcement) achieved superior mechanical performance, establishing hybrid natural fibre composites as a promising eco-friendly alternative to conventional materials.

Abstract: Aim: This research evaluates the strength and stability of hemp, kenaf, and coir fiber reinforced composites produced by compression molding for industrial applications. Materials and Methods: Hemp, kenaf, and coir fibers are blended with a polymer matrix and compression molded. Group 1 (Traditional) This article illustrates the effective fabrication of hybrid fiber. Ultimately stabilized to a medium percentage of resin (75%). Group 2 (Composite) hemp, kenaf & coir blended fiber source more tensile, compressive strength and minimum water absorption rate and wear behavior. Result: The best were the kenaf composites, then hemp water resistance, and they all possessed good thermal stability. Compression molding assisted in enhancing fiber bonding. Conclusion: Compression molding improved the adhesion of fiber and matrix. Kenaf composite exhibited maximum strength, hemp exhibited maximum water resistance, and all of them exhibited good thermal stability.

Abstract: Lignin is the largest component of biomass and the second most abundant natural polymer. Lignin-based products are commonly applied as binders, and are utilized for polymer applications. The purpose of this study is to use lignin as an admixture in mortar. The lignin dissolved in 1M NaOH solution, and the ratio was 1:5 by weight. The lignin contents utilised in this study were 1%, 2%, 3% by weight of cement and a cement water rasio of 0.4. Lignin as an admixture in mortar increased the flowability value. The flowability value increased as the lignin content rose. the highest compressive strength and flexural strength occured at 1% lignin content. They were 35.71 MPa and it was 5.49 MPa, at the age of 28 days. The longest setting time was obtained at 3% lignin content for initial setting time of 285 minutes, and final setting time of 540 minutes. Based on the results of the setting time test, it has been determined that the more lignin was mixed in, the longer the setting time will be. Therefore lignin as an admixture to the mortar makes changes its characteristics.

Abstract: Fused deposition modeling (FDM) has several advantages, including design freedom, part customization, and ease of realizing complex geometries. However, there exist some challenges with the process; these include but are not limited to porosity, anisotropy, roughness, and material compatibility. This study is focussed on the additive manufacturing of polymer composites (short carbon fiber reinforced polyamide 6) through the process of FDM. Such 3D-printed parts are very lightweight and possess superior mechanical properties, which makes them a potential candidate for applications where a high strength-to-weight ratio is desired. The combination of FDM parameters, namely nozzle temperature, layer height, and flow rate, are studied in this work. The effect of variation in these parameters on the porosity and flexural strength is recorded following the Taguchi design of experiments. In calculating porosity, the weight difference between the printed part and the CAD part is used. For the flexural test, the standard three-point bending test is performed. The optimal combination of parametric settings is observed to be the same for minimum porosity and maximum flexural strength. Moreover, the flow rate is identified as a significant parameter for FDM printing of the composite material under study. The prints obtained at a raster angle 0˚/90˚ and on-edge orientation are observed to have better flexural strength than the prints at a raster angle ±45˚ and flat orientation.

Abstract: The objective of this research is to investigate how the quantity of laminate layers impacts the Ramie-Eglass fiber hybrid composite utilized in the Jaloe Kayoh material, specifically concerning mechanical properties such as tensile strength and flexural properties. In this research, the authors conducted tensile and flexural testing on composites with varying quantities of laminate layers. The research findings indicate that incorporating a laminate layer into the hybrid composite positively affects its mechanical properties. The composites with 5 laminate layers had the maximum tensile strength, measuring approximately 59.79 MPa, and the highest tensile modulus, measuring around 3.15 GPa. The results suggest that adding a suitable number of laminate layers can enhance the composite's resistance to tensile stress and preserve its structural stiffness. Furthermore, the composite consisting of 6 laminate layers demonstrated the largest elongation at break, measuring at 2.04%. This result suggests that the material has a commendable ability to withstand strain before reaching its breaking point. For flexural properties, the configuration with 3 layers of lamina shows the most optimal results with flexural strength of around 161.11 MPa, flexural strain of around 0.021, and flexural modulus of around 3.47 GPa. Therefore, this configuration is recommended as the most optimal to withstand flexural stress on Jaloe Kayoh. This study offers valuable insights into the correlation between the quantity of laminate layers and the mechanical properties of Ramie-Eglass fiber hybrid composites. These insights can be utilized to create advanced composite materials for Jaloe Kayoh boats.