scholarly journals Impact of High Temperature on the Compressive Strength of ECC

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xingyan Shang ◽  
Zhoudao Lu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
High Temperature ◽  
Microstructural Characterization ◽  
Cementitious Composites ◽  
Strengthening Effect ◽  
Before And After ◽  
Scanning Electron

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of ECC (engineered cementitious composites) exposed to high temperature up to 800°C was discussed in this paper. The specimens quenching in water gained better mechanical properties than the ones cooling in air. The strengthening effect of quenching for specimens subjected to 800°C was more significant than for the ones subjected to 400°C. The microstructural characterization is examined before and after exposure to fire deterioration by using scanning electron microscopy. Results from the microtest well explained the mechanical properties variation of postfire specimens.

scholarly journals Effect of Different Cooling Regimes on the Mechanical Properties of Cementitious Composites Subjected to High Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jiangtao Yu ◽  
Wenfang Weng ◽  
Kequan Yu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
High Temperature ◽  
Significant Influence ◽  
Microstructural Characterization ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite ◽  
Before And After ◽  
Scanning Electron

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of engineered cementitious composite (ECC) subjected to high temperature up to 800°C was discussed in this paper. The ECC specimens are exposed to 100, 200, 400, 600, and 800°C with the unheated specimens for reference. Different cooling regimens had a significant influence on the mechanical properties of postfire ECC specimens. The microstructural characterization was examined before and after exposure to fire deterioration by using scanning electron microscopy (SEM). Results from the microtest well explained the mechanical properties variation of postfire specimens.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.

Microstructure and Mechanical Properties of Titanium Severely Strained by Means of Friction Roll Processing

2007 ◽  
Vol 561-565 ◽  
pp. 909-912 ◽  
Author(s):  
Mei Qin Shi ◽  
Yoshimasa Takayama ◽  
Hajime Kato
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Texture Evolution ◽  
Electron Back Scatter Diffraction ◽  
Subsequent Annealing ◽  
Severe Plastic Deformation Technique ◽  
Before And After ◽  
Feeding Speed ◽  
Scanning Electron

Severe strain has been introduced to commercially purity (CP) titanium samples by means of friction roll processing (FRP), which represents an alternative severe plastic deformation technique by inducing shear strain. FRP has an excellent possibility of controlling surface microstructure combining with subsequent annealing. The resultant microstructure refinement and texture evolution has been investigated. Hardness of sample was measured to compare mechanical properties of samples before and after FRPed. Parameters including the different indentations given to the sample and sample feeding speed were experimentally conducted to find the optimum condition for investigating effect on microstructure evolution. After subsequent annealing, the evolutions of microstructure and texture were observed by field emission scanning electron microscopy (FESEM) and analyzed by scanning electron microscopy/ electron back scatter diffraction pattern (SEM/EBSP) technique. Transverse texture was found to be the preferred orientation existing in the thin top layer of the sample after FRP and annealed at 823K for 1h.

Effect of Hydroentanglement on Structures and Properties of Wet-Laid Paper Sheets

2019 ◽  
Vol 821 ◽  
pp. 201-205
Author(s):  
Chao Deng ◽  
Xian Gyu Jin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Air Permeability ◽  
Water Absorbency ◽  
Structures And Properties ◽  
Before And After ◽  
Properties Of Materials ◽  
Scanning Electron

In this work, pulp/lyocell wet-laid paper sheets have been consolidated by hydroentanglement techniques. Scanning electron microscopy has been used to evaluate the structures of wet-laid paper sheets before and after hydroentanglement. Wet tensile strength along longitudinal (preferential) and transverse directions show the effect of hydroentanglement techniques on the mechanical properties of wet-laid paper sheets. In addition, the air permeability and water absorbency properties of materials have been evaluated. The results show that the structures of wet-laid paper sheets become fluffy and fiber entanglements increase after consolidation. The wet tensile strength values of wet-laid paper sheets at the longitudinal and transverse directions are increased by 109.0% and 78.7%, respectively after hydroentanglement. The air permeability and water absorbency of wet-laid paper sheets are increased by 957.6% and 137.0%.

scholarly journals Microstructural Characterization of the Anisotropy and Cyclic Deformation Behavior of Selective Laser Melted AlSi10Mg Structures

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 825 ◽  
Author(s):  
Mustafa Awd ◽  
Felix Stern ◽  
Alexander Kampmann ◽  
Daniel Kotzem ◽  
Jochen Tenkamp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Selective Laser Melting ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Laser Melting ◽  
Structural Anisotropy ◽  
Scanning Electron

The laser-based fusion of metallic powder allows construction of components with arbitrary complexity. In selective laser melting, the rapid cooling of melt pools in the direction of the component building causes significant anisotropy of the microstructure and properties. The objective of this work is to investigate the influence of build anisotropy on the microstructure and mechanical properties in selective laser melted AlSi10Mg. The alloy is comprehensively used in the automotive industry and has been one of the most frequently investigated Al alloys in additive manufacturing. Using specimens produced in three different building orientations with respect to the build platform, the anisotropy of the microstructure and defects will be investigated using scanning electron microscopy and microcomputed tomography. The analysis showed a seven-times higher pore density for the 90°-specimen compared to the 0°-specimen. The scanning electron microscopy revealed the influence of the direction of the cooling gradient on the constitution of the eutectic phase. Mechanical properties are produced in quasi-static and fatigue tests of variable and constant loading amplitudes. Specimens of 0° showed 8% higher tensile strength compared to 90°-specimens, while fracture strain was reduced almost 30% for the 45°-specimen. The correlation between structural anisotropy and mechanical properties illustrates the influence of the building orientation during selective laser melting on foreseen fields of application.

scholarly journals Compressive strength and microstructure of modified coffee exocarp cement-based composites

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9059-9074
Author(s):  
Zehua Zhu ◽  
Cheng Cheng ◽  
Debin Zhu ◽  
Dewen Liu ◽  
Yafei Zhang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Portland Cement ◽  
Vacuum Extraction ◽  
X Ray Diffraction ◽  
Extraction Technology ◽  
X Ray ◽  
Scanning Electron

Portland cement-based composites were prepared with coffee exocarp (pretreated with water or NaOH) via vacuum extraction technology. An orthogonal test was adopted to analyze the influence of various factors on mechanical properties of the composite. The morphology and composition of the pretreated coffee exocarp and composites were analyzed via environmental scanning electron microscopy and X-ray diffraction, respectively. The results showed that the coffee exocarp content and vacuum extraction time significantly affected the compressive strength. An addition of 10% coffee exocarp had a slight negative effect on the mechanical properties but enhanced the crack inhibition and overall toughness of the composite. The scanning electron microscopy and X-ray diffraction results showed that the composite containing coffee exocarp pretreated with 4% NaOH solution had the highest density and exhibited the best properties due to mechanical interlocking between the coffee exocarp and cement. After 28 d of curing, the composites exhibited a maximum compressive strength of 15.72 MPa, a mass that was approximately 37% less than that of ordinary Portland cement samples, and a bulk density of 1.5 g/cm3 to 1.6 g/cm3. Hence, the produced biocomposites could be used for low-load pavements, providing a new type of economical building material.

FTIR Spectroscopy Analysis of PLA Biocomposites Reinforced with Hemp Fibers

2020 ◽  
Vol 850 ◽  
pp. 112-117
Author(s):  
Anete Smoca
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Spectroscopy Analysis ◽  
Hemp Fiber ◽  
Hemp Fibers ◽  
Three Samples ◽  
Before And After ◽  
Molded Parts ◽  
Scanning Electron

In this study, Fourier-transform infrared spectroscopy (FTIR) of polylactide (PLA) biocomposites reinforced with hemp fibers were analyzed. Three samples of biocomposites with different proportions of hemp fibers in the PLA matrix were compared. Hemp and PLA fibers in biocomposite were evenly blended using carding technology. Samples before and after water absorption were compared using scanning electron microscopy (SEM). Thermoset treated polylactide and hemp fiber biocomposites have high mechanical properties, that allow to reduce the number of materials in the product. The developed biocomposite can be used as a slab material and for molded parts of furniture, etc.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

scholarly journals Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Glassy State ◽  
Nanofibrillated Cellulose ◽  
Dynamic Mechanical Properties ◽  
Initial Modulus ◽  
Surface Modified ◽  
Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

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