In this research, the hybridization effect of Semic arbon fibers (SCFs) with glass fibers on tensile pr operties and burning rate of composites as compared to glass fibers reinforced e poxy matrix composite was investigated. In this reg ard, four plies composites with different arranging of SCFs and glass fibers w ere fabricated by hand lay-up method. The hybridiza tion of SCFs with glass fibers was caused reducing tensile strength and ela stic modulus of these composites as compared to gla ss fibers reinforced composite. But the failure strain of these composit es was improved. Also, the obtained results showed that both failure strain and tensile strength have important role on energy abso rption in composites that the effectiveness of thes e factors proportionate SCFs and glass fibers ratio. The results of rate and the cross section of burning showed that with increasi ng SCFs to glass fibers ratio, the flame retardancy of composite increases.

In this study, 4 composite layers of plain carbon fiber fabric, plain glass fiber fabric and carbon-glass [carbon-glass-carbon-glass] fiber fabrics, are tested under high speed impact (118 m/s) with flat or half-spherical projectile in impact angles of 0, 30 and 45 degrees compared to the normal impact, and the amount of damage as well as their ballistic limit was studied. Results showed that with increase in the impact angle striked with the flat projectile, the ballistic limit decreased by 30% and the damage area decreased by 36%. Also, with the increase in the impact angle striked with the half-spherical projectile in speed of 118 m/s on 4 layers of carbon fiber fabric and glass fiber fabric, the ballistic limit increased by 25% and the damage area decreased by 40%. The maximum damage area and ballistic limit was in 4 layers of glass fiber fabric and the minimum damage area and the ballistic limit was observed in 4 layers of carbon fiber fabric, that with integration of these 2 fabrics and generating 4 layer fabric of carbon-glass, the high ballistic limit of glass fiber fabric and low damage area of 4-layer carbon fabric is achieved in 4 layer carbon-glass laminate.

One method for rehabilitation of weak and problematic soil properties is rehabilitation by using physical added material such as fibers. In this paper, effect of glass fiber on rehabilitation of clay soil mechanical properties is studied. The main goal of this paper is evaluation of how added glass fiber to clay soil can affect engineering properties of soil, particularly unconfined compression strength and elasticity modulus of reinforced soil. In this research five different composition of soil and glass fiber (0.5 to 2.5) per cent with 11, 13 and 15 per cent water content are used. In order to study the effect of water content and glass fiber, unconfined compression tests have been done on clay soil reinforced by fiber glass and unreinforced clay soil. Obtained results in this research show that adding glass fiber to clay increases highly unconfined compression strength and elasticity modulus of the reinforced clay. Increasing fiber glass and water content, increases failure strain and makes difference in failure situation of the reinforced clay. Increasing water content in samples, increases ductility and failure strain of reinforced clay and decreases unconfined compression strength and elasticity modulus.

This study investigates the effect of steel fibers and its hybrid form with glass fiber on the properties of cement composites. The studied mechanical properties included compressive strength and flexural strength, and the energy absorption rate of the specimens was determined by the flexural toughness. In the mixtures, Portland cement and calcium aluminate have been used as bonding agents the mixes containing 2% steel fiber (% of total volume of the mixture), 2% AR Glass fiber, and hybrid of these fibers were made of glass fiber (2% steel fibers and 2% glass fiber), the length of these fibers was 25 mm. The compressive strength test was performed at the age of 1, 7, 28 and 90 days. Speciments made with calcium aluminate cement had higher compressive strength due to quick formation of microstructure compared to Portland cement mixtures, so that 90-day compressive strength of Portland cement mix was lower compared to the 1-day compressive strength of Calcium aluminate concrete. Incorporating 2% steel fibers also had a slightly enhancing effect on compressive strength. Flexural strength test was carried out at 28 and 90 days. The steel fibers create appropriate mechanical bond with the cementitious matrix, and the ultimate flexural strength was about 2 times higher than non-fibers specimen, due to the congrated geometry of the steel fibers. Substituting glass fiber also increased the ultimate flexural strength due to the high aspect ratio glass fibers and the well formed Interfacial transition zone (ITZ). The hybridization of the aforementioned fibers with steel fibers increases the bending strength due to the synergistic effect. The energy absorption content of the cementitious mix measured by flexural toughness index shows that this energy absorption content increases with the hybridization of the glass and steel fibers, so that the hybrid specimen made with Portland cement had a flexural toughness of 34.4 Nm. The glass fiber increased the toughness due to its excellent energy absorption. The steel fibers in the mixed increased the area under the flexural loading cureve and prevent the mixture from being destroyed by the first crack. In the shrinkage test results the control specimen with the two types of cements did not differ significantly, but the addition of 2% of the fibers (steel fiber and glass fiber) reduced shrinkage by their limiting effect on length change and propagation of micro cracks. When the percentage of glass fiber become higher, similar to the hybrid mix, the shrinkage was reduced further. This experiment was performed uo to 270 days and it was observed that the shrinkage of the hybrid specimen made with Calcium aluminate cement reduced by 65.5% compared to the plain concrete. In this study, the RCMT was carried out at 90 days. The results indicate that the penetration rate of the hybrid specimens and the glass fiber mixtures were lower than those of the steel fibers incorporated mixed. Also, in comparing two types of calcium aluminate cement and Portland cement, specimen made with calcium aluminate cement, the chloride ion penetration was lower than those made with Portland cement due to the improved Interfacial transition zone (ITZ) and less porosity of this type of cement.

This research investigated experimentally the effect of useing of 3D fiberglass fabric in the energy absorption in glass fiber metal laminate composite made by vacuum assisted resin transfer molding (VARTM) method. The prepared GLARE is made of two or three Aluminum 2024 facing sheets and E glass/epoxy as nano composite core. Composite core section for samples of glass fiber plain weave has been composed of plain weave glass fiber 200 g⁄m^2 , 3D fiberglass fabric samples consists of 3D fiberglass fabric to thickness of 5 mm, resin R510 and hardner H515. All panels fabricated using VARTM method in section glass fiber plain weave in fiber volume fraction of 71%. Low velocity impact tests were conducted using by drop weight device at the impact energy of 50 and 80 j. The results of the low velocity impact experiments show that the amount of resistance of impact plain weave samples in comparison to the 3D fabric in various energy levels is more and better. In applications where weight is an effective agent component, the weight of glass fiber plain weave base samples is less than 3D fiberglass fabric samples.

Investigating the behavior of fiber/polymer composite structures and the effect of various factors on their mechanical properties is vital in defining the design, manufacturing and troubleshooting process. In this paper, the changes in the mechanical behavior of the E-glass fiber/polyester composite structure under the influence of thermal preloading on the glass fiber fabric have been studied. For this purpose, in addition to performing mechanical tests, scanning electron microscopy (SEM) has been used to investigate the manner and nature of glass fiber breakage as well as the cross-sectional area of fiber fracture. Also, the changes in the state of the bonding agent on the surface of the glass fibers used in the woven fabric, in the initial conditions of as received fabric and also in its secondary conditions after applying thermal preload by placing it in an oven at 350 °C temperature was studied. In this regard, the Attenuated Total Reflectance (ATR) infrared spectroscopic analysis method was used. The results indicate a significant decrease in the mechanical properties of the manufactured composite, as a result of applying thermal preloading on plain fabric made of E-class glass fibers, before the impregnation stage with unsaturated polyester resin.

In this research, the high-velocity impact behavior of sandwich structures with FML skins and glass fiber-reinforced syntactic foam core was conducted, experimentally. The syntactic foam was produced using epoxy resin and glass microballoon with 30%, 40%, and 60% volume fractions. The FML skins on each side of the cores comprised two layers of glass fiber-reinforced polymer composite (GFRP) and one aluminum layer sheet. In addition, a series of reinforced samples were created using 30% volume fraction of microballoon and 15% chopped glass fibers. The samples were subjected to high-velocity impact tests using a one-stage gas gun and a conical-head aluminum projectile. The results were used to investigate the effects of microballoon volume fraction and glass fiber-reinforced syntactic foam core on the high-velocity impact behavior of structures. The results showed that increasing the microballoon volume fraction from 20% to 30% decreased the projectile residual velocity and increased the ballistic limit velocity and penetration energy. Furthermore, reinforcing syntactic foam with glass fiber significantly affected the high-velocity impact behavior of the structure.

In this study, nanocomposites based on epoxy, nano-silica and short glass fibers were prepared with hand molding method. The resin material consisted of epoxy resin and polyamine. Nano-silica and glass fibers, with average length of 6 mm, were added to epoxy polymer matrix in three levels 0, 0.75 and 1.5 wt.% for nano-silica and 5, 10 and 15 wt.% for glass fibers, respectively. After sample preparation, tensile tests are performed to study tensile properties of composites and results were compared and analyzed. Results showed that by adding 0.75 wt.% nano-silica, tensile strength, elastic modulus and elongation increased and by addition 1.5 wt.% of nano-silica the mentioned properties decreased. On the other hand, adding just glass fibers enhanced elastic modulus continuously and declined tensile strength of the nanocomposite. Furthermore, simultaneous presence of glass fibers and nano-silica caused an enhancement in elastic modulus and a reduction in tensile strength and elongation at break.

In this research, polyethylene is used in the form of granules as an additive with soil, because it is very similar to sand grains in terms of formation, and it increases the possibility of obtaining specifications. On the other hand, glass fibers are also used to increase the shear strength of the soil. The change trend of soil CBR value was investigated in three scenarios: adding only glass fibers, adding only granulated polyethylene and adding a combination of glass fibers and granulated polyethylene. By adding a small percentage of glass fibers (0.75%), the CBR value increased slightly, but with an increase in the percentage of fibers, a decrease in CBR resistance was seen. On the other hand, by increasing the percentage of polyethylene granules in the soil, the CBR resistance of the soil increased significantly, but with an increase in the percentage of polyethylene granules to 7%, a decrease in CBR resistance was observed. In addition, the CBR test was performed on two composite samples in such a way that the first sample was made with 0.75% polyethylene and 0.75% glass fibers and the second sample was made with 3% polyethylene and 0.75% glass fibers. In the combined sample of polyethylene granules and glass fibers in equal percentage, no increase in soil CBR number was observed, but adding 3% of polyethylene along with 0.75% of glass fibers to the soil increases the CBR value in the soil.

The addition of glass fibers has been used to stabilize the unsuitable clay of Rey city to reduce the subsidence in the strip foundations due to the improvement of resistance parameters. The combination of glass fibers with clay and the effect of using this additive on the stabilization of clay fine-grained clay (CL) were investigated in the laboratory. Soil samples in the natural state as well as in the combined state with different percentages of glass fibers equal to 0.2, 0.4 and 0.6, 0.8 and 1% of the dry weight of the soil were used for laboratory tests including standard compaction test, California load ratio test and direct cutting. Were located. The results show a decrease in unit weight of maximum soil volume and an increase in optimum moisture content, as well as a California load-bearing ratio by adding this material to the clay. The amount of adhesion and the internal friction angle resulting from the direct shear test increase with increasing percentage of glass fibers. After laboratory studies, the effects of using modified soil with improvement depths of one meter, two meters, four meters for strip foundations with widths of 0.75, 1.50 and 2.25 meters with the help of Plaxis2D software show that by increasing the percentage of mixing glass fibers In fine-grained clay soils, the amount of foundation deposition is reduced, while the reduction of foundation deposition on soil mixed with 0.8% glass fibers is more than soil mixed with 1% glass fibers. The reduction rate of the strip foundation with a width of 0.75 m with a mixing percentage of 0.8 glass fibers and a depth of improvement of 4 m is 1.57 cm. ،he reduction rate of the desired foundation with widths of 1.5 and 2.25 meters is equal to 2.29 and 2.72 cm, respectively