Papers by Keyword: Reinforcement

Abstract: Plastic bags are one of the most widely used packaging materials in industries. Lower production cost, lightweight and high strength envisage its use in food packaging, carrier, and transportation industries. However, these plastic bags are non-biodegradable and cause serious water and soil pollution. It is one of the most thrust areas of research to overcome this problem in the current world. In the present investigation, fabrication, and characterization of an environmentally friendly and biodegradable "jute fibre reinforced paper composite" and "reinforcement free paper laminate" subjected to drop test were done. The standard procedure of the "MIL-STD-810G 516.6" drop test was followed. The adhesion between the matrix (paper) and reinforcement (jute fibre) was produced by applying a chemical-free adhesive made of flour and water. There were four different types of samples: single paper (SP), reinforcement-free paper laminate (RFPL), single-layer jute fibre reinforced paper composite (SLJPC), and double-layer jute fibre reinforcement paper composite (DLJPC). The microstructural characterization of the fractured surface after the drop was done using a scanning electron microscope operated at a voltage of 20 kV. The DLJPC samples had the maximum density and envisage drop-strength of 7 times as compared to the SP samples having the lowest density. The drop-strength exhibited linear regression with density for all the samples. The microstructure of the as-received matrix showed a non-homogeneous distribution of fibres along with micro-voids which were susceptible sites for the fracture. Unlike as-received matrix fibres distribution, the reinforcement fibres were aligned in two mutually perpendicular directions which leads to its strengthening. Hence, it can be said that the non-uniform structural properties envisaged by the as-received matrix can be compensated by uniformly distributed structural properties of the as-received reinforcement when both come together as a composite. The primary fracture mechanism of SP samples exhibited fibre breaking along with a few fibres' delamination. However, in the case of the RFPL sample, the nature of adhesion applied was capable to hold both the interfaces and the primary fracture mechanism was fibre breaking. It is suggested that the adhesive applied transmitted load through the interfaces. Unlike SP sample, the RFPL sample exhibited some adhesive pull-off. The fractured surface of the SLJPC sample showed that the matrix did not subject to fracture, however, reinforcement did fracture hence the load was transferred from matrix to reinforcement followed by a rupture of the reinforcement. Therefore, the primary fracture mechanism for the SLJPC sample was reinforcement rupture. The DLJPC sample showed a delamination of matrix and reinforcement.

Abstract: This article suggests a calculation procedure for the parameters of complete moment-curvature deformation diagrams with a down leg that can be used for the calculations of the multistorey monolithic building frameworks taking into account the specifics of reinforced concrete. To construct complete deformation diagrams for bending elements, a non-linear deformation model is used that is based on using the physical diagrams of the concrete and reinforcements to calculate the inner moments of cross-sections at all loading stages via balance and strain compatibility equations. Using this model, the authors researched complete moment-curvature deformation diagrams for the elements with different percentages of longitudinal tensile reinforcement that changes the bending properties of the structure. We used grade А500 steel as the reinforcement. The parameters of the tensile reinforcement diagram were determined in the tension testing of samples with constant deformation rates. The performed computer tests to calculate the moment-curvature diagram parameters for reinforced concrete beams reinforced with grade А500 efficiency rods and conventional grade A400 reinforcement rods with different longitudinal reinforcement congestion rates helped the authors assess the bending properties of the elements under conditions approaching their destruction and determine their efficient use in the calculations of building frameworks taking into account the redistribution of forces.

Abstract: The article suggests the use of glued reinforced wooden beams with increased load-bearing capacity. The beam is provided with reinforcing elements in the grooves, namely, in the lower zone – prestressed flexible bundles made of composite, and in the upper zone – steel rods. The analysis of structural behaviour of the beam and the location of the reinforcing elements, the calculation of the bearing capacity of beams and evaluation of the effectiveness decision on material and Flexural rigidity. Composite rods can be prestressed to increase the efficiency of the reinforcement and increase the beam stiffness and load-bearing capacity. Installation of reinforcing elements along the line of action of the main tensile stresses in a wooden beam creates tension in them, which allows the use of flexible bundles and leads to a decrease in the complexity of their installation in the lower grooves, and, therefore, reduces the complexity of manufacturing a wooden beam as a whole.

Abstract: Aluminum 6061 alloy-based alloys were used to make various motor vehicle parts such as connecting wire, O-ring, circular blocks, disc brakes and aircraft primary components, but the use of alloys was restricted in some of their applications due to their low strength, poor stiffness and high friction wear resistance. Hybrid Aluminium Metal Matrix Composites are achieved the potential mechanical properties compared to single reinforced composite materials. Tribological behaviour of hybrid composites were optimized by Response Surface Methodology (RSM) using Design of experiment statistical analysis. The contribution of various parameters rotational speed, sliding distance and axial load on hybrid composite materials were evaluated by Analyses of Variance (ANOVA). For each output response, a multilayer linear equation was used to examine the relationship between the parameters. According to the results, hybrid compounds provide greater adaptability and reliability in the development of a component of the product depending on the reinforcement composition and structure.

Abstract: Reinforced geopolymeric mortars were manufactured by mixing mining tailings, fine sand, Ichu fibers (in variable percentages), sodium hydroxide and water. The microstructure of the obtained mortars consisted of a continuous geopolymer binder phase with sand particles and Ichu fibers dispersed within the binder phase. The real density and average porosity of the reinforced mortars was 2.74 g/cm3 and 34%, respectively. It was possible to verify the influence of the addition of Ichu fibers on the mechanical response in uniaxial compression of the studied mortars, due to the poor interface between the geopolymer and the fibers. The mechanical results revealed a systematic reduction of the maximum compressive strength when the volume of Ichu fibers in the mortar mixtures was increased. On the other hand, a higher degree of deformation was evidenced in mortar mixtures containing a greater amount of Ichu fibers, reaching deformation values ​​of up to 5%. The maximum resistance values ​​found were from 2.87 to 20.76 MPa for samples with 8 and 0 vol.% of Ichu fibers added, respectively.

Abstract: The subject of the article is a comparison of behavior of a precast reinforced concrete infill shear walls with an opening with different types of reinforcement. These are the walls that can ensure stiffness of the frame structure against horizontal load. Studied walls with an opening represent cases of how the wall can be reinforced prior to the implementation of an additional opening. The influence of the so called “sleeping reinforcement” is studied. This is a reinforcement that would take effect only after the additional opening has been made. The wall elements are first subjected to experimental verification. Subsequently, the results from the experiments are verified by non-linear models, which represent the individual elements during the experiment. Based on these models, a parametric study is performed, where the influence of an opening size in these infill shear walls is studied on their load - bearing capacity and stiffness.

Abstract: A growing demand for advanced composite materials as well as diverse design requirements offering significant weight savings in comparison to conventional materials have all contributed to a growing interest in composite materials. This review paper is focused on Powder Metallurgy (P/M) process to fabricate magnesium based metal matrix composites. The excellent oxidation and corrosion resistance and low density of Silicon carbide have made it a popular material even at very high temperatures. Despite their very high specific strength, magnesium matrix composites possess excellent cast ability, good damping capabilities, and greater machinability. Therefore, this review paper discusses the importance, fabrication, and properties of magnesium matrix composite materials for industry applications. An examination of the properties of recently produced magnesium matrix composites by various researchers is presented in this review paper.

Abstract: Polyethylene, elastomer, and date palm fibre are all readily available, it have an positive impact on growth of new composite materials with desirable features and characteristics. There are many different types of composites, but they all have the same goal: to create a new material with greater qualities than the constituent materials. Date palm fibre was employed to reinforce a composite matrix made of polyethylene (PE) plastic and elastomer. To find out the tensile, impact, and bending strength values of composites by weight fractions of 25% (75:25), 35% (65:35), and 45% (55:45), this research set out to find (55:45). Composites with a weight percentage of 25% (75:25) had less Tensile strength (TS) 1.213 MPa, though mixtures with weightage proportion of 45% (55:45) had the maximum TS of 2.613 MPa. The minimum tensile strain value was discovered in composites with a weight fraction of 25% (75:25), while the maximum tensile strain value was identified in composites with weight fraction of 45 percent (0.0067). (55:45). 45 % (45-55) weight ratio mixture had the minimum impact strength of 45321 kJ/mm², while the 25 percent (75-25) weight ratio mixture had the maximum impact strength of 17721.41 kJ/mm². A 25 percent weight fraction (75:25) composite had the lowest bending strength measurement result (1.816 MPa), whereas a 35 percent weight fraction (65:35) composite had the highest measurement result (4.9 MPA) in this category. At 75:25 (75:25), the bending strain of the composite was at its highest, with a value of 0.0216

Abstract: Stainless steel reinforcing bars show excellent corrosion resistance in concrete exposed to harsh environments. In this combined electrochemical and surface analytical work, an explanation for this behavior is proposed. XPS surface analytical results (thickness, composition of the passive film and of the interface beneath the film) obtained on black steel, FeCr alloys, and a series of stainless steels after exposure to alkaline solutions simulating concrete are reported. Pitting potentials were determined in the same solutions with electrochemical experiments. It is shown that the pitting potentials of the steels can be related to the Cr (III) oxy-hydroxide and Mo (VI) content in the passive film. It is proposed to calculate a Cr and Mo oxide equivalent similar to the well-known pitting resistance equivalent number (PREN). A correlation between the critical chloride content in concrete (reported in literature for CEM II A/LL and CEM I) and the pitting potential for carbon steel, Fe12%Cr alloy, DIN 1.4301 and DIN 1.4571 stainless steels is proposed to link results of solution analysis and performance in concrete.

Abstract: The use of inorganic matrix in fiber reinforced composites has been studied in the last years for strengthening applications in masonry construction. At the moment different systems are available after a technical qualification that allows a safe and certified use in construction industry. In the field of historical masonry the benefits of such materials are well known respect to the most known Fiber Reinforced Polymers (FRPs), due to a very poor substrate. In this study the experimental results of a larger research program are presented and discussed. A Fiber Reinforced Cementitious Matrix (FRCM) system has been tested in order to measure the tensile mechanical properties and bond properties respect to different substrates: clay masonry and natural tuff masonry. Tensile properties of the FRCM composite were measured in presence of a cement mortar, and results are illustrated. In addition pull-off tests and bond shear lap tests of the FRCM are described and commented respect to the two substrates. Tensile tests on glass fiber mesh and glass FRP (GFRP) connectors were performed and results are presented in the paper.