Papers by Keyword: Glass Fiber

Abstract: The microwave absorbing properties of multi-layer carbon/carbon fiber composites, designed to function as radar absorbing structures (RAS), were studied over the X-band frequency range (8.0-12.4 GHz). High-frequency electromagnetic properties of various fibers (glass, carbon) and particulate filler (carbon black) are investigated as the major constituent materials of the RAS. Free space measurement depicts the perfect reflecting properties of carbon fiber composites (S₁₁ = 0 dB, S₂₁ = −40 dB). In the two-layered composite laminate (impedance transformer/reflecting substrate), the use of carbon black is necessary in the impedance transforming layer to obtain the high level of microwave absorbance and frequency tuning. Through the layer combination of the glass-fiber composite (thickness = 2.45 mm) containing carbon black (3% in weight) and carbon fiber composite as reflecting substrate, S₁₁ can be reduced to as low as −40 dB at the frequency of 11.7 GHz, maintaining a low level of S₂₁. The results demonstrate that RAS can be efficiently designed with the laminates of fiber reinforced composites with impedance transforming layer (glass fiber with suitable amount of carbon black) and perfectly reflecting substrate (carbon fiber).

Abstract: The paper deals with the influence of geosynthetic reinforcement systems on the quality of asphalt bonding layers. A reinforcing element in the form of a fiberglass grid is incorporated into the road structure between two asphalt layers to prevent the formation of cracks and to reduce the tendency of their subsequent propagation throughout the asphalt layers. At the same time, however, they form a potential weak interlayer on which adjacent asphalt layers may slip. The total 90 drilled cores taken from a laboratory-produced two-layer slabs were subjected to the Leutner shear test. The selection of individual specimens took into account both the type of reinforcement element and the amount of applied bituminous emulsion.

Abstract: Glass fiber reinforced cement (GRC) is a new type of composite material formed by using alkali-resistant glass fiber as a reinforcing material and cement paste or cement mortar as a matrix. GRC is widely used in construction engineering. However, the durability of GRC is still a major problem in engineering applications, especially GRC materials have been in the hot and humid building engineering environment for a long time. The alkaline environment of the cement matrix will cause serious erosion of the glass fiber, and Will significantly reduce the mechanical properties such as flexural strength and toughness of GRC. In this paper, ordinary Portland cement is mixed with active mineral admixtures such as fly ash and silica fume to reduce the alkaline environment of GRC matrix, and to delay the erosion rate of glass fiber and increase the flexural strength and compressive strength of GRC; At the same time, the effects of different hot and humid building engineering environments on the mechanical properties of GRC were studied.

Abstract: It is studied that effects of different amounts of steel fiber and glass fiber on the compressive strength, flexural strength, and compression ratio and bond strength of styrene-acrylic emulsion modified mortar under different ages. The results show that the compressive strength, flexural strength and bond strength of mortar increase with the increase of steel fiber content, and the toughness improvement effect is obvious. With the increase of glass fiber content, mortar compressive strength, flexural strength and bond strength first increases and then decreases. Combined with SEM analysis and theoretical calculation to analyze the mechanical strength mechanism of fiber reinforced polymer mortar.

Abstract: In this research, the results of different weight percentage of glass fiber (30, 40 & 50), cement (0, 3 & 6) and polyester resin (70, 60 & 50), on the properties of glass fiber-cement-polyester composites are investigated. The specimens are prepared by hand lay-up technique. All the specimens are tested for tensile and flexural strength as per ASTM standards. Results showed that escalation in glass fiber wt.% improved the tensile strength (by 9% at 40 wt.% and 17% at 50 wt.%) and flexural strength (by 10% at 40 wt.% and 16.5% at 50 wt.%). Whereas an increase in cement weight percentage decreases tensile strength and increases flexural strength. The failure of the sample is due to glass fiber pull out and rupture of the matrix, under tensile load.

Abstract: Moisture absorption of natural fiber-based composites is one of the major problems in outdoor applications. The present study deals with the effect of moisture absorption on mechanical and thermal properties of unmodified/modified Date Palm Leaf (DPL) with glass fiber-based hybrid composites. Natural fibers were modified with alkaline treatment to improve fiber and matrix bonding. Conventional hand lay-up technique is used to fabricate the composites with varying different wt.% of treated and untreated short DPL with constant wt.% of glass fiber and prepared with random oriented manner. The combine effect of hydrophilic and hydrophobic nature find out as the study based upon the natural with synthetic fiber hybrid composites. Mechanical behaviour of the epoxy-based hybrid composites were characterized by using tensile, flexural and hardness test. The results revealed that significant improvement in mechanical properties by the addition of different weight percentage of modified DPL. Different thermal properties of the composites were described by using Thermo Gravimetric Analyzer (TGA) and Differential Scanning Calorimetric (DSC). Morphological investigation was carried out to by using scanning electron microscope. All the properties of untreated natural fiber reinforced composites were mostly affected by the influence of water absorption as compared with chemically treated based composites.

Abstract: This study was designed to examine the consequences of lamination sequence, fiber orientation and hybridization on tensile, flexural, physical, and inter-laminar properties of Jute-epoxy laminated composites and its hybrid. These laminates are partially biodegradable hence environment-friendly. Here six laminated specimens were fabricated using hand lay-up techniques with 4 layers of fiber or 40% fiber loading as per the ASTM standard. Samples were prepared with three different orientation of 0⁰, 30⁰ and 60⁰ to the loading direction. The experimental outcome revealed that composite with 30⁰ fiber orientation gives a better result in flexural, microhardness, and interlaminar shear strength. Generally, Final failure was due to delamination, fiber pull-out, fiber failure or matrix cracking. Scanning electron micrographs were used for improved understanding of fracture mechanics. A substantial quantity of voids, improper alignment, fiber waviness and heterogeneous interface were found resulted in premature failure.

Abstract: In this paper some sandwich bars made from classical materials (polystyrene core, glass fiber) but combined in order to obtain an original material, are made. For these new sandwich bars, some dynamic parameters are studied, such as: damping factors per unit mass and length, eigen frequency.

Abstract: A highly porous structure of a gypsum product creation is possible due to the porisation of gypsum mass, using new types of complex gas-forming components. At the same time, it is necessary to determine the technological conditions for the optimal formation of porous gypsum products structure and methods for increasing their strength. The article proposed to use dispersed calcium carbonate and aluminum sulphate, which interaction is the reaction with the release of СО₂ for the porisation of the gypsum cast mixture. Micro-reinforcing additives, such as polymeric, basalt and glass fibers were introduced into gypsum composition together with building gypsum and finely ground calcium carbonate to improve the physico-mechanical properties of gas-gypsum. The best results were shown by the gas-gypsum, which included fiberglass. Glass fiber was pre-ground to a specific surface of 190-240 m² / kg, in order to improve further the physico-mechanical properties of gas-gypsum.

Abstract: Natural fibers are widely used for reinforcement in polymer composite materials and proved to be effectively replacing synthetic fiber reinforced polymer composites to some extent in applications like domestic, automotive and lower end aerospace parts. The natural fiber reinforced composites are environment friendly, have high strength to weight ratio as well as specific strengths comparable with synthetic glass fiber reinforced composites. In the present work, hybrid epoxy composites were fabricated using calotropis procera and glass fibers as reinforcement by hand lay-up method. The fibre reinforcement in epoxy matrix was maintained at 20 wt%. In 20 wt% reinforcement of fibre, the content of calotropis procera and glass fibre were varied from 5, 10, 15 and 20 wt%. The dry sliding wear test as per ASTM G99 and three body abrasive wear test as per ASTM G65 were conducted to find the tribological properties by varying speed, load, distance and abrasive size. The hybrid composite having 5 wt% calotropis procera and 15 wt% glass fibre showed less wear loss in hybrid composites both in sliding wear test as well as in abrasive wear test which is comparable with 20 wt% glass fibre reinforced epoxy composite which marked very low wear loss. The SEM analysis was carried out to study the worn out surfaces of dry sliding wear test and three body abrasive wear test specimens.