Papers by Keyword: Tensile Strength

Abstract: The article addresses the issue of determining the dependence between the tensile strength of GFRP (Glass Fiber Reinforced Polymer) reinforcement and temperature. Figuring out this dependence is crucial for designing reinforced concrete structures exposed to fire. The newly published generation of standards does not specify any material characteristics of FRP reinforcement at elevated temperatures. The design equations are derived only for steel reinforcement, although this standard allows for the use of FRP reinforcement in the design of concrete structures. For this reason, and based on the available and published experimental data, a robust database of results expressing the decrease in GFRP reinforcement tensile strength as a function of temperature was created and supplemented by the results of our own tests. The characteristic value of the tensile strength was determined as 5% quantile according to the requirements of current a new standard by using two methods: data binning and quantile regression. The resulting (characteristic) dependence of the decreasing tensile strength of GFRP reinforcement on temperature shows zero strength at 550 °C and considers the effect of polymer matrix degradation on the behavior of the reinforcement. The determined curve can be used as a basis for the design of GFRP reinforcement in structures exposed to fire in accordance with EN standards.

Abstract: It has been studied how SiO₂ nanoparticles affect the mechanical and electrical properties of low-density polyethylene (LDPE). The tensile strength, microstructural features, and AC breakdown characteristics of LDPE containing silicon dioxide (SiO₂) nanoparticles were investigated in this work. The concentrations of filler were adjusted to 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 3.0 wt%, and 4.0 wt%. The samples were prepared by using Haake machine and shaped by compression moulding, and a sphere to sphere electrode arrangement was used for AC breakdown testing. The breakdown reliability was assessed using the Weibull distribution. Molecular interaction and nanoparticle dispersion were analysed using Raman spectroscopy and scanning electron microscopy (SEM), respectively. The findings demonstrated that mechanical strength and breakdown voltage increases with filler concentration, reaching a maximum at 2.0 wt% SiO₂. When compared to pure LDPE, the AC breakdown voltage increased by 27.54% at this concentration. SEM pictures showed a homogeneous dispersion of nanoparticles, while Raman spectra verified improved interfacial bonding. AC breakdown voltage above 2.0 wt% shows decrease value due to agglomeration of nanoparticles. According to this study, LDPE insulation performance is best enhanced by 2.0 wt% SiO₂.

Abstract: The article addresses the challenges and methodologies for enhancing the properties of asphalt concrete utilized in the Republic of Armenia. Environmental factors, including abrupt temperature fluctuations, precipitation, and black ice, coupled with the escalating load on road surfaces, necessitate the development of high-performance asphalt concrete. To this end, both local mineral resources and various industrial waste materials have been investigated for their potential to augment the properties of bitumen. It has been determined that the most effective additive-modifiers are synthesized from waste materials, specifically aluminum palmitate and aluminum oleate. These additives enhance bitumen properties and are likely to fortify the chemisorption bonds at the interface between bitumen and the mineral phase. The study further examined the variation in bitumen properties based on the type and quantity of synthesized additive-modifiers incorporated. Results indicate that the most substantial improvement in modified bitumen is achieved at a concentration of 3 mass percent of the additives relative to the weight of the bitumen.

Abstract: Steel is the most used material for concrete reinforcement; however, it performs poorly in aggressive environments (e.g. coastal areas) owing to corrosion (moisture and chlorides). This study aims to analyse the tensile strength of steel and glass fibre-reinforced polymer (GFRP) bars through laboratory testing to assess their feasibility and application in construction. Steel bars were tested by ASTM E8/E8M–22, obtaining values of 606.61 MPa (Ecuador) and 676.46 MPa (Peru), whereas GFRP bars were tested following ASTM D7205/D7205M–21 (1,000 MPa). The analysis indicated that GFRP bars offer structural advantages (suitable for elements in coastal zones with low to moderate seismic activity), environmental benefits (lower CO₂ emissions during production), and enhanced durability (corrosion resistance).

Abstract: This review paper focuses on the major factors of deterioration, specifically rutting, stripping, and moisture effects, which are key factors affecting road pavements globally. Stressing the need to tackle these distresses, the study aims to improve the performance of asphaltic courses via advancing bio-based reinforcement materials, especially sisal fiber. The paper tries to analyze the mechanism of rutting in asphalt mixtures with a special reference to sisal fibers as an agent to increase resistance to permanent deformation. However, fiber reinforcement with the asphalt mixtures are also briefly described in the subject with the favorable effects of tensile strength, fatigue strength and crack propagation strength. The review further focuses on the ability of fiber reinforcement to enhance pavement service life, address pavement deterioration issues, and improving the service life of road pavements.

Abstract: Bioplastics or biopolymers are being developed as an alternative to tackle the problem of polymer waste, which causes pollution and greenhouse gas emissions. Cellulose derived from corn cobs can be a biopolymer alternative to synthetic polymers. Cellulose derived from corn cobs can replace conventional petroleum-based polymers as an alternative plastic material. Incorporating ZnO into the biopolymer matrix is projected to result in favourable characteristics and allow for a wider range of applications. This study aims to investigate the changes in the characteristics of bioplastics derived from corn cob waste and starch upon the incorporation of ZnO, with a special emphasis on mechanical properties and electrical conductivity. FTIR analysis shows that the incorporation of ZnO exhibited no impact on the structure of the bioplastic. Scanning electron microscopy (SEM) analysis revealed that the ZnO microparticles' morphology is irregular and rough. The average size of ZnO particles incorporated into the biopolymer matrix was 0.623 μm. Mechanical tests showed a positive correlation between the amount of ZnO and the tensile strength of bioplastics. The assessment of the electrical conductivity of the Bioplastic/ZnO composite indicates a notable enhancement with the inclusion of ZnO. Electrical conductivity shows a progressive increase from 2.13x10^-15 S/m to 3.23x10^-12 S/m, 7.42x10^-11 S/m, and 2.03x10^-10 S/m with the incorporation of ZnO as much as 0.03, 0.06, and 0.09 g, respectively. Generally, incorporating ZnO into bioplastics can enhance their tensile strength and electrical conductivity.

Abstract: ’This study investigates the mechanical performance of concrete reinforced with recycled polyethylene terephthalate (PET) fibers obtained from discarded plastic bottles, aiming to promote sustainable waste reuse in construction materials. Previous studies on PET fiber reinforced concrete have mainly examined the influence of fiber length and content separately, without considering their combined effects on mechanical properties. In this work, the interactions between fiber length, volume fraction, and mechanical behavior were systematically analyzed using a Central Composite Design (CCD) within the framework of Response Surface Methodology (RSM). Concrete incorporating recycled PET fibers was evaluated at three volume fractions (0.3%, 0.8%, and 1.3%) and three lengths (20 mm, 40 mm, and 60 mm), while maintaining a constant water-to-cement ratio. Sixty specimens were tested to assess both fresh and hardened properties. The greatest loss of workability occurred for the mix containing 1.3% fibers with a length of 60 mm, corresponding to about a 25% reduction compared with the control. Response Surface Methodology (RSM) based on a Central Composite Design (CCD) identified 0.3% fiber content and 40 mm length as the optimal combination, representing the mix that simultaneously maximized both compressive (26 MPa) and tensile strengths (3 MPa) according to the predictive model.

Abstract: The influence of filler type and content on the wettability and interfacial bonding between thermoplastic elastomer (TPE) and polypropylene (PP) by using the injection overmolding process was investigated in this study. Calcium carbonate (CaCO₃) and talcum (Talc) masterbatchs, ranging from 0 to 40 percent by weight (wt%), were mixed into the PP matrix as fillers. The bond strength of TPE overmolded onto PP composites was characterized by the tensile and tear tests. Good compatibility was observed between TPE and PP filled with various amounts of CaCO₃ and Talc. In the case of the tensile test, the crack initiation stress, ultimate tensile strength, strain at break, and bond energy were found to decrease with increasing filler content. The results obtained from the tear test indicated that the propagation strength, ultimate tear strength, strain at break, and bond energy of injection overmolded TPE-PP filled with various CaCO₃ contents did not significantly change compared to those obtained from Talc. This can be attributed to the high reinforcing efficiency of Talc in comparison with CaCO₃, which can enhance the stiffness and thermal resistance of the PP matrix. As a result, the contact area becomes more resistant to molecular diffusion of TPE chains, particularly at high Talc loadings (30 and 40 wt%), leading to the reduction of interfacial bonding.

Abstract: This study investigates the mechanical degradation of nylon 6,6 under tensile stress, induced by accelerated aging via ultraviolet (UV) radiation [1-3]. Specimens were fabricated and exposed to controlled UV doses, simulating outdoor weathering conditions. Tensile properties were evaluated, revealing a significant reduction in tensile strength and elongation at break with increasing UV dose. The predominant degradation mechanism was photo-oxidation, evidenced by polymer chain scission and the formation of functional groups altering the material's molecular structure[4,5]. Specimen surfaces exhibited cracks and fissures, contributing to mechanical strength loss. These findings are critical for nylon 6,6 applications in telecommunications and energy industries, where UV exposure is unavoidable. Understanding this degradation is essential for optimizing the durability and reliability of critical infrastructure. This study lays the foundation for developing advanced protective materials and coatings, enhancing the safety and efficiency of outdoor systems.

Abstract: This study investigates the effects of fiber type and hybridization on the tensile properties of epoxy composites produced using the temperature-controlled vacuum-assisted resin transfer molding (VARTIM) method. Tensile strengths and fracture behaviors are examined by fabricating 6-layer glass fiber-reinforced composites [G6], 6-layers carbon fiber-reinforced composites [C6], and hybrid composites consisting of six layers of glass and carbon fibers [H1] and [H2]. The microstructures of the composites are analyzed using an optical microscope, and tensile tests are conducted in accordance with ASTM standards. Tensile tests are performed at a constant speed and room temperature, and the fracture surfaces after tensile testing are analyzed using a Stereo Microscope. The results showed that the highest tensile strength is achieved in the carbon fiber-reinforced composite (CFRP), with an increase of approximately 123% compare to the glass fiber-reinforced composite (GFRP). Hybrid composite exhibits the reduced tensile strength compare to CFRP, with decreases of 23% for H2 and 29% for H1, respectively, whereas, increased the fracture toughness of the tested samples. Additionally, fracture surface analysis reveals that GFRP exhibits incomplete separation of the fractured surfaces, while CFRP shows a brittle and clean fracture surface. This study highlights the significant impact of fiber type and hybridization on the tensile property and fracture behavior of epoxy composite, demonstrating the better tensile performance of CFRP, while improving the fracture toughness and manufacturing cost of both GFRP and Hybrid composite.