Effect of Milling Time on the Physical and Mechanical Properties of Celsian-Mullite Composites Synthesized from Coal Fly Ash

2012 ◽  
Vol 1373 ◽  
Author(s):  
Jorge López-Cuevas ◽  
David Long-González ◽  
Carlos A. Gutiérrez-Chavarría
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Milling Time ◽  
Coal Fly Ash ◽  
Physical And Mechanical Properties ◽  
Cold Isostatic Pressing ◽  
Planetary Mill ◽  
Degree Of Crystallinity ◽  
Structural Applications ◽  
Flexural Tests

ABSTRACTFour Celsian (Ba0.75Sr0.25Al2Si2O8)/Mullite (Al6Si2O13) composites, with potential structural applications at high temperatures, are synthesized from coal fly ash (byproduct of a Mexican coal-burning power plant, constituted mainly by SiO2 and Al2O3). Nominal Celsian/Mullite weight ratios studied are 80/20, 60/40, 40/60 and 20/80. Mullite is synthesized separately at 1600ºC/2h and then mixed with a Celsian precursor mixture previously calcined at 900°C/5h. During this process the Celsian phase is formed by a solid state reaction at 1100-1400ºC/5h. Prior to this, the reacting mixture is milled in a planetary mill during 1 or 2h and then compacted by uniaxial and cold isostatic pressing. The microstructure and phase composition of the synthesized composites are characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM/EDS). Their dynamic Young’s modulus is measured by an ultrasonic technique, and their mechanical strength is evaluated from flexural tests carried out at room temperature. The expected phases are obtained in all cases, although with some differences with respect to their expected relative proportions, according to the studied nominal compositions. In general, the longest milling time employed produced samples with the largest degree of crystallinity and density, as well as with the best microstructural characteristics and mechanical properties.

Effect of Processing Parameters on the Properties of Glass–Ceramics from Arc-Melting Slag of Incineration Fly Ash

2011 ◽  
Vol 399-401 ◽  
pp. 864-868
Author(s):  
Han Qiao Liu ◽  
Guo Xia Wei ◽  
Yin Liang ◽  
Jun Lan Yang
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Milling Time ◽  
Bending Strength ◽  
Compaction Pressure ◽  
Glass Ceramics ◽  
Physical And Mechanical Properties ◽  
Processing Parameters ◽  
Arc Melting ◽  
Melting Slag

The glass-ceramics were made of arc-melting slag from incinerator fly ash mixed with glass cullet additive by sintering method. The effects of ball milling time and powder compaction pressure on the microstructure, physical and mechanical properties of the glass–ceramics were respectively investigated. Results showed that with milling time delaying, granularity of the parent glass evidently reduces, the major phases of glass–ceramics have no change but the diffraction peaks present intensive trend, the crystal sizes of glass–ceramics decrease, the properties such as volumetric densities, compressive strength, bending strength and toughness are improved, the appropriate milling time is 6h with fifty percent of the volume (d50 value) of 10.62μm. The physical and mechanical properties first increase and then decrease with compaction pressure increasing, and the optimal compaction pressure is 60MPa.

Effect of Mechanical Activation on the Synthesis of Ba-Celsian and Sr-Celsian using Precursor Mixtures Containing Coal Fly Ash

2016 ◽  
Vol 1812 ◽  
pp. 89-94
Author(s):  
Claudia M. Lopez-Badillo ◽  
Jorge López-Cuevas ◽  
Carlos A. Gutiérrez-Chavarría ◽  
José L. Rodríguez-Galicia ◽  
Elia M. Múzquiz-Ramos
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Solid State ◽  
Mechanical Activation ◽  
Solid State Reaction ◽  
Milling Time ◽  
Coal Fly Ash ◽  
Raw Material ◽  
Attrition Mill ◽  
Sintered Materials

ABSTRACTBaAl2Si2O8 and SrAl2Si2O8 were synthesized by solid-state reaction of stoichiometric mixtures of either BaCO3 or SrCO3 with coal fly ash and Al2O3. The mixtures were mechanically activated in an attrition mill for up to 12 h and then reaction-sintered at 900-1300 °C, aiming to promote the formation of BaAl2Si2O8 and SrAl2Si2O8 as well as the conversion from their hexagonal (Hexacelsian) into their monoclinic (Celsian) forms, which is associated with improved mechanical properties in the sintered materials. Especially in the case of SrAl2Si2O8, the formation of Celsian was favored at relatively low sintering temperatures by increasing milling time. Although only the SrAl2Si2O8 composition was fully converted into Celsian, the Hexacelsian to Celsian conversions obtained for the mechanically-activated BaAl2Si2O8 composition were significantly higher than those previously reported in the literature for this compound. This could be attributed to the use of coal fly ash as raw material, which contains mineralizers that promote the mentioned conversion.

Physical and mechanical properties of epoxy/Kota stone dust/fly ash hybrid composites for light duty structural applications

2021 ◽  
Author(s):  
Virendra Rajput ◽  
Neelesh Kumar Sahu ◽  
Alok Agrawal ◽  
Gaurav Gupta
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Hybrid Composites ◽  
Physical And Mechanical Properties ◽  
Light Duty ◽  
Stone Dust ◽  
Structural Applications

Experimental Investigation and Micro-Structural Evolution Analysis of CNT & Fly Ash Reinforced Aluminium Matrix Composites

2015 ◽  
Vol 830-831 ◽  
pp. 429-432 ◽  
Author(s):  
Udaya ◽  
Peter Fernandes
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Fly Ash ◽  
Ball Milling ◽  
Milling Time ◽  
Structural Evolution ◽  
Matrix Composites ◽  
Evolution Analysis ◽  
Ball Milling Time ◽  
Al Matrix

The paper illustrates Carbon nanotubes reinforced pure Al (CNT/Al) composites and fly ash reinforced pure Al (FA/Al) composites produced by ball-milling and sintering. Microstructures of the fabricated composite were examined and the mechanical properties of the composites were tested and analysed. It was indicated that the CNTs and fly ash were uniformly dispersed into the Al matrix as ball-milling time increased with increase in hardness.

Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lime Water ◽  
Diffraction Patterns ◽  
Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

The physical and mechanical properties of fly ash geopolymers with various S/L ratios

2020 ◽  
Author(s):  
N. H. Teng ◽  
H. C. Yong ◽  
M. M. A. Abdullah ◽  
N. Yong-Sing ◽  
K. Hussin
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Physical And Mechanical Properties

scholarly journals Long-Term Physical and Mechanical Properties and Microstructures of Fly-Ash-Based Geopolymer Composite Incorporating Carbide Slag

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6692
Author(s):  
Xianhui Zhao ◽  
Haoyu Wang ◽  
Linlin Jiang ◽  
Lingchao Meng ◽  
Boyu Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Drying Shrinkage ◽  
Fine Aggregate ◽  
Property Development ◽  
Industrial Solid Waste ◽  
Carbide Slag

The long-term property development of fly ash (FA)-based geopolymer (FA−GEO) incorporating industrial solid waste carbide slag (CS) for up to 360 d is still unclear. The objective of this study was to investigate the fresh, physical, and mechanical properties and microstructures of FA−GEO composites with CS and to evaluate the effects of CS when the composites were cured for 360 d. FA−GEO composites with CS were manufactured using FA (as an aluminosilicate precursor), CS (as a calcium additive), NaOH solution (as an alkali activator), and standard sand (as a fine aggregate). The fresh property and long-term physical properties were measured, including fluidity, bulk density, porosity, and drying shrinkage. The flexural and compressive strengths at 60 d and 360 d were tested. Furthermore, the microstructures and gel products were characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The results show that the additional 20.0% CS reduces the fluidity and increases the conductivity of FA−GEO composites. Bulk densities were decreased, porosities were increased, and drying shrinkages were decreased as the CS content was increased from 0.0% to 20.0% at 360 d. Room temperature is a better curing condition to obtain a higher long-term mechanical strength. The addition of 20.0% CS is more beneficial to the improvement of long-term flexural strength and toughness at room temperature. The gel products in CS−FA−GEO with 20.0% CS are mainly determined as the mixtures of sodium aluminosilicate (N−A−S−H) gel and calcium silicate hydration (C−S−H) gel, besides the surficial pan-alkali. The research results provide an experimental basis for the reuse of CS in various scenarios.

scholarly journals Global analysis of DEF damage to concretes with and without fly-ash

2022 ◽  
Vol 15 (3) ◽  
Author(s):  
Nicole Pagan Hasparyk ◽  
Dioice Schovanz ◽  
Francieli Tiecher ◽  
Selmo Chapira Kuperman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Global Analysis ◽  
Physical And Mechanical Properties ◽  
Test Method ◽  
Cement Matrix ◽  
Negative Effects ◽  
Ettringite Formation ◽  
Pozzolanic Cement ◽  
Over Time

Abstract Delayed Ettringite formation (DEF) is an internal expansive reaction that can damage concrete. DEF is strongly influenced by the temperature, above about 60-65°C, and other factors involving cement chemistry especially, but also its physical characteristics. The exposure environment over time also promotes a condition to increase deterioration from DEF. Expansions results from secondary ettringite formation are progressive and can lead concrete to microcracking impacting its performance and durability over time. Several concrete structures are pointed to be severely attacked by DEF, and test method as well a better comprehension on this pathology is necessary to promote specific and proper preventive measures to avoid future damages. Furthermore, compared to alkali-silica reaction, DEF occurs more readily and aggressively, and sometimes prematurely, depending on several factors, such as type of cement, concrete mix design, exposure conditions, among others. This paper involves an overall analysis of the behavior of concretes with two types of Portland cements (High early-strength cement and a Portland pozzolanic cement, with fly-ash) in relation to DEF process. Several data from a laboratory study where DEF was induced through a specific thermal curing procedure are presented and discussed. The analyses involved the assessment of physical, mechanical, and expansive properties besides microstructural monitoring of samples from concretes over time. These experiments allowed detecting high values of expansions from DEF (up to 1.2%) in the concrete without fly ash. The mechanical properties were severely impacted from this deleterious process; as expansions increased, losses in the mechanic and elastic properties were verified. Expansion levels in the order of 0.5% prompted remarkably high reductions and, at about 1% the losses were relevant for both strengths (tensile and compressive) and modulus of elasticity, of 60% and 80%, respectively, in the presence of cement without fly-ash. Concrete microstructure has indicated massive formations of ettringite as well as micro-cracking and the fragility of the cement matrix because of DEF. On the other hand, expansion up to 0.2% did not promote important negative effects on the properties of concrete, especially with the pozzolanic cement tested. Furthermore, an overall approach with several correlations between physical and mechanical properties was taken to obtain different levels of deterioration for a concrete presenting DEF.

scholarly journals STUDY OF FLY ASH GEOPOLYMER AND FLY ASH/SLAG GEOPOLYMER IN TERM OF PHYSICAL AND MECHANICAL PROPERTIES

2020 ◽  
Vol 5 (4) ◽  
pp. 187-198
Author(s):  
Ng HUI-TENG ◽  
Heah CHENG-YONG ◽  
Mold Mustafa Al Bakri ABDULLAH ◽  
Ng YONG-SING ◽  
Ridho BAYUAJI
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Physical And Mechanical Properties
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