Papers by Keyword: Mechanical Performance

Abstract: In hot and humid climates, premature pavement failures, such as rutting and surface deformation, continue to be significant problems. High temperatures shorten the stiffness and durability of asphalt mixtures by encouraging the softening and aging of the binder. Using the right additives to increase asphalt's mechanical strength and resistance is essential for prolonging pavement life. Hence,this study investigates the optimization of binder content and mechanical performance of asphalt mixtures incorporating garnet waste at various proportions. The optimum bitumen content was prepared utilizing Marshalll mix design method then evaluated the mechanical performance using Marshall stability and resilient modulus. 75 samples of AC14 mixture were produced with addition of 0%, 5%, 10%, 15%, and 20% garnet. As a result, 15% of garnet mixture demonstrates the highest stability of 24,300 N and stiffness of 8,450 N/mm. Meanwhile, resilient modulus analysis observed that 5% of garnet exhibit the optimal propotions, with increased modulus of 5709 MPa at 25 °C and maintained at 40 °C with modulus of 1,343 MPa. The binder aggregate bond was weakened when increasing the proportions of garnet in the mixture as well as reducing the structural of samples. Thus, incorporating garnet waste shows a sustainable additive to improve asphalt mixture properties while promoting environmental sustainability through industrial waste reuse.

Abstract: Incremental forming represents a versatile and cost-effective alternative to conventional sheet forming processes. In recent years, its application has been extended to polymers and composite materials. Among these, natural fiber-reinforced thermoplastics offer several advantages, as natural fibers are widely available, contribute to the semi-biodegradability of the composites, and serve as effective reinforcements for polymer matrices. This experimental study examines the mechanical properties of flax woven fabric-reinforced polypropylene composites, fabricated via compression molding, and their suitability for producing spherical caps through cold incremental forming. A range of features was investigated to assess the effectiveness of incremental forming on these biobased composites and to compare the mechanical performance of undeformed and deformed laminates.

Abstract: Present demands for weight reduction of vehicles to decrease the carbon footprint in the transport industry have increased the need for lightweight tubes. In this paper, composite tubes are drawn from two aluminum tubes and reinforcements with the aim of maximizing mechanical performance while maintaining low weight. The reinforcements are placed between the two aluminum tubes and are made from blanks of 22MnB5 steel or carbon fiber laid in different quantities and patterns. The compressive stresses in tube sinking are used to hold the reinforcements in the composites without the need for resins and energy-intensive heating or curing cycles. The composites are weighed, and their performance is evaluated by mechanical test. Bending tests reveal an increase in the bending strength of the reinforced tubes by 15% for both composites reinforced by carbon fiber and 22MnB5 steel. However, the composites made from carbon fiber have higher stiffness and lower weight. The bending strength and residual stresses of composites manufactured with different carbon fiber layouts and quantities are evaluated to determine their performance. Increasing the carbon fiber content did not improve the stiffness and ultimate tensile strength of the composites, indicating the compressive stresses from drawing and carbon fiber content should be optimized to achieve the best mechanical performance.

Abstract: CO₂ emissions from cement production have significantly increased, leading to the search for alternative materials that optimize the process and reduce environmental impact. In this context, the present study investigates the use of microsilica (MS) and fan shell powder (PCA) as cement replacements. Material characterization tests were conducted, and six mix designs were made, including 5% PCA and 10% MS replacements individually, as well as combinations of 10% MS with 5%, 7.5%, and 10% PCA. Additionally, compression strength properties were analyzed at 3, 7, and 28 days, and flexural strength at 7 and 28 days. The findings regarding mechanical strength were favorable, except for the mix with 10% MS and 10% PCA, which indicates the maximum substitution percentage. Furthermore, a CO₂ emission analysis was conducted according to the Greenhouse Gas Protocol, achieving a reduction of up to 11.16% compared to the control concrete. In conclusion, the study demonstrates that the combination of 10% MS and 5% PCA is the optimal replacement, improving compressive strength by 6.99% and flexural strength by 1.33%, while reducing CO₂ emissions by 10.44%.

Abstract: Optimizing the mechanical properties of aluminum to titanium welds is crucial to establish applications for dissimilar lightweight structures in the aerospace industry. In this context, solid-state welding technologies have proven effective in terms of short joining cycles, allowing the combination of cost-effective production and structural weight optimization. However, metallurgical effects between aluminum and titanium in the joint interface are still not completely understood due to differences in physical as well as chemical characteristics. In this study, aluminum alloy 6013 was welded to Ti6Al4V by refill Friction Stir Spot Wel ding, including systematic variations of Mg and Si alloying element content in the used AA6013 sheets. In total five different Al alloys were welded to the titanium to investigate the influence of Mg and Si during processing. Apart from the material selection, the weld strength is mainly influenced by the intermetallic compound thickness at the interface, which in turn primarily depends on the exposed temperature cycle. Consequently, major interest during this study was given on the temperature evolution, interfacial features and the global mechanical properties.

Abstract: Concrete is the most widely used construction material, but its environmental impact and reliance on finite resources have driven the need for more sustainable solutions. This research paper presents the optimization of bamboo fiber and wood ash as supplementary materials in concrete to enhance its mechanical performance and sustainability. A powerful statistical technique known as Response Surface Methodology was employed to systematically investigate the effects of varying bamboo fiber and wood ash content on the compressive and flexural strengths of concrete. The optimal combination of 0.36% bamboo fiber and 13.43% wood ash resulted in a flexural strength of 3.227 MPa and a compressive strength of 18.444 MPa, demonstrating the significant potential of these sustainable materials to improve concrete's mechanical properties. The findings of this study provide valuable insights for the construction industry, highlighting the feasibility of utilizing bamboo fiber and wood ash to develop more durable and environmentally friendly concrete mixtures that can contribute to a more sustainable built environment.

Abstract: Limestone fillers are increasingly recognized as a sustainable alternative to cement and sand in mortar and concrete mixtures, driven by environmental concerns over the excessive use of natural resources and raw materials. This study investigates the potential exploitation of different limestone fillers, waste products of the quarrying industry, in the production of cementitious composites. The investigation includes the physico-mechanical characterization of a number of mixtures with different percentages of limestone fillers used as partial replacement to sand. The results show that increasing the limestone filler content negatively influences the mechanical performance of the hardened end-products, decreases their density and increases their open porosity. At the same time, increased clay particle content in the limestone filler decreases the workability of the fresh mixtures.

Abstract: This scientific paper presents a comparative analysis of the mechanical characteristics of PLA samples fabricated through conventional AM methods and AM then ultrasonically compacted. The study aims to assess the potential advantages and limitations of ultrasonic compaction of PLA AM samples, as a reinforcing manufacturing technique. The methodology involves the fabrication of PLA samples using AM processes, then ultrasonically compact part of them to make a comparative study on their mechanical characteristics, including tensile strength. Additionally, the surface morphology and internal microstructure of the samples are analysed using microscopy techniques. The results of the study provide insights into the mechanical performance and structural integrity of the ultrasonically compacted samples compared to the conventionally PLA AM samples. The findings highlight any potential improvements or limitations in terms of mechanical properties, such as strength, durability, and overall performance.

Abstract: This paper investigates the valorization of slag in cement production in order to obtain a sustainable mortar and participate in protecting the environment. The study evaluated the setting time, hydration heat, mechanical strengths, drying shrinkage, sulfuric acid and sulfate attack of mortars. These mortars are based on Portland cement (PC), slag cements containing 10%, 30% and 50% slag and alkali-activated slag (AAS) using 6% and 9% of sodium hydroxide (NaOH). The results show that the increase in slag replacement rate increases the setting time accompanied by a drop in initial mechanical strength such that the compressive strength decreased by 30% at two days for a 50% slag substitution; also, it considerably reduces the shrinkage and hydration heat. The resistance to sulfate and sulfuric acid attack increases with the slag replacement rate. NaOH-activated slag mortar is the most resistant binder to sulfate attack and sulfuric acid, but it develops a lower mechanical strength and a more significant shrinkage than PC mortar. X-ray diffraction (XRD) analysis carried out on binder paste shows the formation of the same main hydration products in PC and slag cement with a small amount of portlandite in the last binder. Calcium silicate hydrate (CSH) and Hydrotalcite are the main hydration products of AAS.

Abstract: Waste can be categorized as organic waste and chemical waste. Organic waste generated from agriculture industry had been proofed to be use in concrete production to enhance the concrete performance. The main purpose of adding the fiber in concrete structure is to control cracking due to plastic shrinkage and to drying shrinkage. Besides, it can also reduce the permeability of concrete, thus, reduce the bleeding of water. Some types of fibers produce greater impact, abrasion, and shatter resistance in concrete. Therefore, this paper reviewed the mechanical properties of concrete containing oil palm and coconut fiber as an additional material in concrete. Coconut fiber length is longer than oil palm fiber. Therefore, in comparison, by adding coconut fiber in concrete up to 5% may reduce the flexural and tensile strength of the concrete due to agglomerate effect of the fiber. In contrast, for oil palm fiber, beyond 5% of addition in concrete will improve the flexural and tensile strength of the concrete due to the length effect of the fiber. By discussing both organic fiber as an additional material to strengthen the concrete, it can contribute to the body of knowledge in term of reducing cracks in concrete. Besides, it will give a better understanding to readers regarding the function of the materials in concrete.