Showing papers on "Flexural strength published in 2013"
TL;DR: In this article, a sisal-jute-glass fiber reinforced polyester composites is developed and their mechanical properties such as tensile strength, flexural strength and impact strength are evaluated by using scanning electron microscopy (SEM).
Abstract: The composite materials are replacing the traditional materials, because of its superior properties such as high tensile strength, low thermal expansion, high strength to weight ratio. The developments of new materials are on the anvil and are growing day by day. Natural fiber composites such as sisal and jute polymer composites became more attractive due to their high specific strength, lightweight and biodegradability. Mixing of natural fiber with Glass-Fiber Reinforced Polymers (GFRPs) are finding increased applications. In this study, sisal–jute–glass fiber reinforced polyester composites is developed and their mechanical properties such as tensile strength, flexural strength and impact strength are evaluated. The interfacial properties, internal cracks and internal structure of the fractured surfaces are evaluated by using Scanning Electron Microscope (SEM). The results indicated that the incorporation of sisal–jute fiber with GFRP can improve the properties and used as a alternate material for glass fiber reinforced polymer composites.
588 citations
TL;DR: In this paper, the porosity-dependent relationship between compressive strength and splitting tensile strength of cement mortar has been evaluated and interpreted in terms of its porosity, and the authors first reviewed the existing porosity strength relationships (Ryshkewithch, Schiller, Balshin and Hasselman model) and assessed the suitability of existing relationships.
541 citations
TL;DR: Graphene oxides (GOs) nanosheets were prepared by oxidization and ultrasonic dispersion to increase the tensile/flexural strength of the corresponding cement composites as discussed by the authors.
491 citations
TL;DR: SEM observations of the indentation induced cracks indicate that the polymer network causes greater crack deflection than the dense ceramic material, pointing out the correlation between ceramic network density, elastic modulus and hardness of PICNs.
400 citations
TL;DR: In this article, the influence of B 4 C on the mechanical and Tribological behavior of Al 7075 composites is identified, and the test results showed increasing hardness of composites compared with the base alloy because of the presence of the increased ceramic phase.
Abstract: In the present investigation, the influence of B 4 C on the mechanical and Tribological behavior of Al 7075 composites is identified. Al 7075 particle reinforced composites were produced through casting, K 2 TiF 6 added as the flux, to overcome the wetting problem between B 4 C and liquid aluminium metal. The aluminium B 4 C composites thus produced were subsequently subjected to T6 heat treatment. The samples of Al 7075 composites were tested for hardness, tensile, compression, flexural strengths and wear behavior. The test results showed increasing hardness of composites compared with the base alloy because of the presence of the increased ceramic phase. The wear resistance of the composites increased with increasing content of B 4 C particles, and the wear rate was significantly less for the composite material compared to the matrix alloy. A mechanically mixed layer containing oxygen and iron was observed on the surface, and this acted as an effective insulation layer preventing metal to metal contact. The coefficient of friction decreased with increased B 4 C content and reached its minimum at 10 vol% B 4 C.
394 citations
TL;DR: The study aimed to assess the mechanical performance of seven bulk-fill RBCs by determining their flexural strength, reliability, and modulus of elasticity, with x-tra fil achieving the highest values, while Filtek Bulk Fill and Venus Bulk Fill achieved the lowest.
Abstract: The study aimed to assess the mechanical performance of seven bulk-fill RBCs (Venus Bulk Fill, Heraeus Kulzer; SureFil SDR flow, Dentsply Caulk; x-tra base and x-tra fil, VOCO; Filtek Bulk Fill, 3M ESPE; SonicFill, Kerr; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent) by determining their flexural strength (σ), reliability (Weibull parameter, m), flexural modulus (Eflexural), indentation modulus (YHU), Vickers hardness (HV), and creep (Cr). The significant highest flexural strengths were measured for SonicFill, x-tra base, and x-tra fil, while x-tra base, SureFil SDR flow, and Venus Bulk Fill showed the best reliability. The differences among the materials became more evident in terms of Eflexural and YHU, with x-tra fil achieving the highest values, while Filtek Bulk Fill and Venus Bulk Fill achieved the lowest. The enlarged depth of cure in bulk-fill RBCs seems to have been realized by enhancing the materials' translucency through decreasing the filler amount and increasing the filler size. The manufacturer's recommendation to finish a bulk-fill RBC restoration by adding a capping layer made of regular RBCs is an imperative necessity, since the modulus of elasticity and hardness of certain materials (SureFil SDR flow, Venus Bulk Fill, and Filtek Bulk Fill) were considerably below the mean values measured in regular nanohybrid and microhybrid RBCs. The class of bulk-fill RBCs revealed similar flexural strength values as the class of nanohybrid and microhybrid RBCs, and significantly higher values when compared to flowable RBCs. The modulus of elasticity (Eflexural), the indentation modulus (YHU), and the Vickers hardness (HV) classify the bulk-fill RBCs as between the hybrid RBCs and the flowable RBCs; in terms of creep, bulk-fill and the flowable RBCs perform similarly, both showing a significantly lower creep resistance when compared to the nanohybrid and microhybrid RBCs.
383 citations
TL;DR: Significant differences between both RBCs were found for DC, E, σ, and Eflexural at all irradiation times and measuring depths, and the factor “RBC” showed the strongest influence on the measured properties.
Abstract: Objectives
The aim of our study was to measure and compare degree of conversion (DC) as well as micro- (indentation modulus, E; Vickers hardness, HV) and macromechanical properties (flexural strength, σ; flexural modulus, Eflexural) of two recently launched bulk fill resin-based composites (RBCs): Surefil® SDR™ flow (SF) and Venus® bulk fill (VB).
335 citations
TL;DR: In this paper, the effects of GPLs on the microstructure and mechanical properties of the Al 2 O 3 based ceramic composites were investigated, and the results show that GPLs are well dispersed in the ceramic matrix.
312 citations
TL;DR: In this article, an additive manufacturing (AM) technique for high strength oxide ceramics was developed, which aimed at directly manufacturing fully dense ceramic freeform components with good mechanical properties.
Abstract: Purpose – The purpose this paper is to develop an additive manufacturing (AM) technique for high‐strength oxide ceramics. The process development aims at directly manufacturing fully dense ceramic freeform‐components with good mechanical properties.Design/methodology/approach – The selective laser melting of the ceramic materials zirconia and alumina has been investigated experimentally. The approach followed up is to completely melt ZrO2/Al2O3 powder mixtures by a focused laser beam. In order to reduce thermally induced stresses, the ceramic is preheated to a temperature of at least 1,600°C during the build up process.Findings – It is possible to manufacture ceramic objects with almost 100 percent density, without any sintering processes or any post‐processing. Crack‐free specimens have been manufactured that have a flexural strength of more than 500 MPa. Manufactured objects have a fine‐grained two‐phase microstructure consisting of tetragonal zirconia and alpha‐alumina.Research limitations/implications...
304 citations
TL;DR: In this article, a component-based joint model was proposed and incorporated into macromodel-based finite element analysis in which beams were modeled with fiber elements to simulate the structural responses of the specimens with severe geometric and material nonlinearity.
300 citations
TL;DR: In this paper, the authors investigated the mechanical properties of ultra high performance fiber reinforced cementitious composites (UHPFRCC) with four different fiber volume fractions within an identical mortar matrix.
TL;DR: In this article, the binding mechanism and properties of alkali-activated fly ash/slag (AAFS) mortars with various ratios of fly ash to slag were investigated by compressive strength test, flexural strength test and water absorption test, drying shrinkage test, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis.
TL;DR: In this article, the effects of substitution of sand with PET processed particles have been investigated with cubic and cylindrical specimens with different water to cement ratios and physical properties of fresh concrete were evaluated.
TL;DR: In this paper, the authors present a review of experimental studies conducted in the area of fiber-reinforced polymer (FRP) anchorage systems applied to reinforced concrete (RC) flexural members.
Abstract: The anchorage of fiber-reinforced polymer (FRP) composites when applied to reinforced concrete (RC) structures as externally bonded reinforcement is an effective means to achieve higher levels of fiber utilization prior to premature debonding failure. Commonly documented anchorage methods for FRP-to-concrete applications demonstrating encouraging results include FRP U-jackets, FRP anchors (also known as spike anchors, among other names), patch anchors (utilizing unidirectional and bidirectional fabrics), nailed metal plates (also known as hybrid bonding), near-surface mounted rods, mechanical fastening, concrete embedment, and mechanical substrate strengthening. Anchorages applied to FRP systems have been verified through experimental testing and numerical modeling to increase the ductility, deformability, and strength of the member and also prevent, delay, or shift the critical mode of FRP debonding failure. Although the benefits of anchorage solutions have now been widely acknowledged by researchers, further studies are required in order to establish reliable design formulations to negate the requirement for ongoing laboratory verification by industry. The present paper is a state-of-the-art review of experimental studies conducted in the area of FRP anchorage systems applied to FRP-strengthened RC flexural members. Available experimental data are compiled and catalogued and an anchorage efficiency factor for each anchorage type under investigation is assigned in order to quantify the anchor’s efficiency. Finally, current shortcomings in knowledge are identified, in addition to areas needing further investigation.
TL;DR: In this article, the state-of-the-art development of short fibre reinforced geopolymer composites and its mechanical properties with emphasis on compressive strength, tensile strength, flexural strength, impact strength and toughness capacities are discussed.
TL;DR: In this paper, the authors evaluated the tensile and flexural properties of hybrid glass fiber-sisal/jute reinforced epoxy composites and found that the incorporation of sisal fiber with GFRP exhibited superior properties.
TL;DR: In general, the inorganic nanoparticle MSNP showed a better or equivalent mechanical reinforcement compared to carbon nanomaterials, and 2D nanostructures (GONPs, MSNPs) are better reinforcing agents compared to one-dimensional (1D) nanostructureures (e.g., SWCNTs).
TL;DR: The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength.
Abstract: This study investigated the effect of sintering temperatures on flexural strength, contrast ratio, and grain size of zirconia. Zirconia specimens (Ceramill ZI, Amann Girrbach) were prepared in partially sintered state. Subsequently, the specimens were randomly divided into nine groups and sintered with different final sintering temperatures: 1,300°C, 1,350°C, 1,400°C, 1,450°C, 1,500°C, 1,550°C, 1,600°C, 1,650°C, or 1,700°C with 120 min holding time. Three-point flexural strength (N = 198; n = 22 per group) was measured according to ISO 6872: 2008. The contrast ratio (N = 90; n = 10 per group) was measured according to ISO 2471: 2008. Grain sizes and microstructure of different groups were investigated (N = 9, n = 1 per group) with scanning electron microscope. Data were analyzed using one-way ANOVA with Scheffe test and Weibull statistics (p < 0.05). Pearson correlation coefficient was calculated between either flexural strength or contrast ratio and sintering temperatures. The highest flexural strength was observed in groups sintered between 1,400°C and 1,550°C. The highest Weibull moduli were obtained for zirconia sintered at 1,400°C and the lowest at 1,700°C. The contrast ratio and the grain size were higher with the higher sintering temperature. The microstructure of the specimens sintered above 1,650°C exhibited defects. Sintering temperatures showed a significant negative correlation with both the flexural strength (r = −0.313, p < 0.001) and the contrast ratio values (r = −0.96, p < 0.001). The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength. Considering the flexural strength values and Weibull moduli, the sintering temperature for the zirconia tested in this study should not exceed 1,550°C.
TL;DR: In this paper, the abaca-jute hybrid composite has better properties than the traditional abaca composite alone in tensile and shear properties, however, the composite is superior to the hybrid composite in flexural and impact strength, and the internal structure of the composite was observed under scanning electron microscope (SEM) and the fractures, voids and fibre delamination were analyzed.
TL;DR: The new short fiber composite differed significantly in its physical properties compared to other materials tested, which suggests that the latter could be used in high-stress bearing areas.
TL;DR: In this paper, the flexural behavior of self-compacting concrete reinforced with straight and hooked end steel fibers at levels of 0.5, 1.0, and 1.5% was investigated.
TL;DR: In this paper, the suitability of granite powder (GP) waste as a substitute material for fine/natural aggregate in concrete production has been investigated, and the experimental parameter was percentage of GP substitution, which indicated that the replacement of natural sand by GP waste up to 15% of any formulation is favorable for the concrete making without adversely affecting the strength and durability criteria.
TL;DR: In this paper, two concrete mixes with 450 and 520 kg/m 3 of ordinary Portland cement and two more mixes of equivalent total cementitious materials with 30% UFGGBS replacement were cast.
TL;DR: In this paper, the effects of nanosilica and different concrete reinforcing fibers including steel, polypropylene and glass on the performance of concrete were evaluated using Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD) techniques.
TL;DR: Production of a dental resin composite with antibacterial activity without significant sacrificing effect on the mechanical properties is desirable in dental material science.
TL;DR: In this article, the effectiveness of textile reinforced mortars (TRMs), as a means of increasing the flexural capacity of reinforced concrete (RC) beams, is experimentally and numerically investigated.
TL;DR: A promising future for new and improved monolithic ceramic restorations, with combined durability and acceptable esthetics is suggested, and monolithic prostheses can be produced with a much reduced susceptibility to fracture.
TL;DR: In this paper, the effect of polypropylene fiber (PPF) on both durability, and physical and mechanical characteristics of concrete for application in concrete sleepers was investigated, where compressive, splitting tensile, and three-point flexural strength, and VeeBee Consistometer (VB) tests were performed to indicate physical and physical characteristic of PPF reinforced concrete.
TL;DR: In this paper, the authors investigated the properties of high strength self compacting concrete (HSSCC) containing nano TiO 2 and industrial waste ash namely as fly ash (FA) for strength enhancement and durability-related characteristics along with rheological, thermal and microstructural properties.
TL;DR: In this paper, the physical, mechanical and fracture behaviour of fly-ash based geopolymer reinforced with cotton fibres (0.3-1.0 ) was described, and it was shown that the appropriate addition of cotton fiber can improve the mechanical properties of the composite.
Abstract: This paper describes the physical, mechanical and fracture behaviour of fly-ash based geopolymer reinforced with cotton fibres (0.3–1.0 wt%). Results show that the appropriate addition of cotton fibres can improve the mechanical properties of geopolymer composites. In particular, the flexural strength and the fracture toughness increase at an optimum fibre content of 0.5 wt%. However, as the fibre content increases, the density of geopolymer composites decreases due to an increase in porosity and tendency of fibre agglomeration.