scholarly journals Stabilization of Indian Fly Ashes with Soils, Cement, and Randomly Oriented Fibers

2012 ◽  
Vol 3 ◽  
pp. 1-8
Author(s):  
Shenbaga R. Kaniraj ◽  
V. Gayathri ◽  
V.G. Havanagi
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Experimental Studies ◽  
Fly Ashes ◽  
Strength Criteria ◽  
Permeability Characteristics ◽  
Polyester Fibers ◽  
Soil Mixtures ◽  
Pavement Base

 Experimental studies were carried out on fly ashes from two Indian thermal power plants, namely Rajghat and Dadri, with the aim of improving the utilization of fly ash in geotechnical engineering applications. It was attempted to improve the engineering performance of fly ash by several means such as by mixing fly ash with soils, cement, and polyester fibers. The research program included the study of: a) physical properties, chemical composition and morphology of the fly ashes; b) compaction, strength, and permeability characteristics of the fly ashes and fly ash-soil mixtures; c) compaction and strength characteristics of fly ash-soil mixtures stabilized with fibers alone, with cement alone, and with both cement and fibers. Results showed that addition of fly ash to soils would result in lighter and stronger fills. Fiber inclusions increased the strength of fly ash-soil specimens significantly and altered their behaviour from brittle to ductile. Even small cement contents increased the strength of the fly ash-soil mixtures significantly. With higher cement contents of up to 18% it was possible to prepare fly ash-cement design mixes that satisfied the strength criteria for pavement base courses.

Experimental Study on Various Mineral Admixtures in Fibre Reinforced Concrete

2019 ◽  
pp. 309-317
Author(s):  
Kavitha E ◽  
Karthik S ◽  
Eithya B ◽  
Seenirajan M
Keyword(s):  
Fly Ash ◽  
Rice Husk ◽  
Power Plants ◽  
Rice Husk Ash ◽  
Thermal Power ◽  
Experimental Studies ◽  
Mineral Admixtures ◽  
Hardened Concrete ◽  
Polypropylene Fibres ◽  
Concrete Production

The quantity of fly ash produced from thermal power plants in India is approximately 80 million tons each year, and its percentage utilization is less than 10%. An attempt has been made to utilize these cheaper materials in concrete production. This thesis aims at investigating the characteristics of fresh concrete and various strengths of hardened concrete made with various mineral admixtures such as fly ash. GGBFS, silica fume. Rice husk ash along with polypropylene fibres in various proportions.  M20 grade concrete is considered for experimental studies with 53grade Ordinary Portland Cement blended with varying percentages of mineral admixtures. The maximum size of coarse aggregate used is 20mm.  Various mineral admixtures such as fly ash. GGBFS.Silica fume. Rice Husk Ash were added concrete in various percentages by partially replacing cement and the optimum percentage of the mineral admixtures will be found.  Based on the obtained values, the admixture with maximum mechanical strength is determined and to this polypropylene fibre is added by varying 0 to 0.5 % by weight of cement to the mix.  The test results obtained were compared and discussed with conventional concrete.

scholarly journals DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

2016 ◽  
Vol 56 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Usman Haider ◽  
Zdenek Bittnar ◽  
Lubomír Kopecky ◽  
Vít Šmilauer ◽  
Jaroslav Pokorny ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Individual Particle ◽  
Particle Analysis ◽  
Fly Ashes ◽  
Alumino Silicate ◽  
Individual Particles

The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

The Suitability of Fly Ash for Use in Concrete According to EN 450 Based on their Particle Size

2018 ◽  
Vol 276 ◽  
pp. 110-115
Author(s):  
Martin Ťažký ◽  
Martin Labaj ◽  
Rudolf Hela
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Raw Materials ◽  
Thermal Power ◽  
Combustion Process ◽  
Thermal Power Plants ◽  
Mechanical Parameters ◽  
Fly Ashes ◽  
The Impact

The by-products of energy industry are nowadays often affected by new limits governing the production of harmful gases discharged into the air. These stricter and stricter criteria are often met by electricity producers by changing the combustion process in thermal power plants itself. Nowadays, the SNCR (selective non-catalytic reduction) application is quite common in the combustion process in order to help reduce the nitrogen oxide emission. This article deals with the primary measures of thermal power plants, which in particular consist of a modified treatment of raw materials (coal) entering the combustion process. These primary measures then often cause the formation of fly ash with unsuitable fineness for the use in concrete according to EN 450. The paper presents the comparison of the physico-mechanical parameters of several fly ashes with a different fineness values. The primary task is to assess the impact of non-suitable granulometry in terms of EN 450 on the other physico-mechanical parameters of fly ashes sampled within the same thermal power plant. Several fly ashes produced in the Czech Republic and surrounding countries were evaluated in this way.

scholarly journals Separation of Cenospheres from Fly Ashes by Floatation Method

2010 ◽  
Vol 13 (1-2) ◽  
pp. 89 ◽  
Author(s):  
L.M. Manоcha ◽  
K.A. Ram ◽  
S.M. Manocha
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Ceramic Particle ◽  
Composition Analysis ◽  
High Concentration ◽  
Fly Ashes ◽  
Power Station ◽  
Different Types ◽  
Chemical Composition Analysis

Fly-ashes are non-combustible mineral residues which are produced from coal in thermal power plants. Four different types of fly ashes were collected from different power station in Gujarat. Characterization through SEM shows that fly ash contains cenosphere i.e. gas bubble containing ceramic particle independent of their bulk density. Floatation technique was used for the separation of cenosphere from fly ash. Two solvents with extremely different densities were used for the separation of cenospheres. All methods gave approximately yield of less than 1 % cenosphere in fly ash. Color of cenospheres varied from gray to almost white and the value of density range from 0.4 – 0.8 g/cc. Further, chemical composition analysis revealed that cenospheres do not contain any high concentration of hazardous elements.

scholarly journals Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1033 ◽  
Author(s):  
Piotr Prochon ◽  
Zengfeng Zhao ◽  
Luc Courard ◽  
Tomasz Piotrowski ◽  
Frédéric Michel ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Biomass Combustion ◽  
Fly Ashes ◽  
Binding Properties ◽  
Alkali Activated ◽  
Modified Fly Ash ◽  
Scanning Electron ◽  
And Calorimetry

The aim of this work was to study the influence of the type of activator on the formulation of modified fly ash based geopolymer mortars. Geopolymer and alkali-activated materials (AAM) were made from fly ashes derived from coal and biomass combustion in thermal power plants. Basic activators (NaOH, CaO, and Na2SiO3) were mixed with fly ashes in order to develop binding properties other than those resulting from the use of Portland cement. The results showed that the mortars with 5 mol/dm3 of NaOH and 100 g of Na2SiO3 (N5-S22) gave a greater compressive strength than other mixes. The compressive strengths of analyzed fly ash mortars with activators N5-S22 and N5-C10 (5 mol/dm3 NaOH and 10% CaO) varied from 14.3 MPa to 5.9 MPa. The better properties of alkali-activated mortars with regular fly ash were influenced by a larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms.

scholarly journals Geotechnical Characteristics of HNPC Fly Ash

2020 ◽  
Vol 9 (5) ◽  
pp. 2007-2012
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Morphological Characteristics ◽  
Geotechnical Properties ◽  
Thermal Power Plants ◽  
Geotechnical Characteristics ◽  
Polyester Fibers ◽  
Ft Ir

Fly ash is the solid waste being produced in largest quantities from thermal power plants in India causing pollution of land and water. It requires bulk utilization which is possible in geotechnical applications such as embankments and subgrades. This necessitates the determination of the geotechnical properties of fly ash from different thermal power plants. The present paper investigates the geotechnical characteristics of fly ash from HNPC, Pedagantyada, Visakhapatnam. The physical and index properties of HNPC Fly ash (HNFA) and its OMC and MDD using I.S. Heavy compaction are first determined. The shear strength, CBR and permeability are then determined at OMC. The study also investigates the influence of polyester fibers and lime as admixture to HNFA in different percentages on Compaction and CBR properties to check their effectiveness in improving HNFA for use in embankments and subgrade. The chemical and morphological characteristics of HNFA, including its specific surface, XRD, SEM and FT-IR spectra have also been determined. The study confirms the suitability of HNFA for use in geotechnical applications and verifies the relative suitability of polyester and lime as admixtures for further improvement of the geotechnical properties of HNFA

scholarly journals Leachability of Heavy Metals from Autoclaved Fly Ash-Lime Building Bricks

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Mehmet TANRIVERDI ◽  
Gül Akar ŞEN ◽  
Tayfun ÇIÇEK ◽  
Sezai ŞEN ◽  
Öznur ÖNEL
Keyword(s):  
Trace Elements ◽  
Fly Ash ◽  
Environmental Effect ◽  
Power Plants ◽  
Thermal Power ◽  
Leaching Tests ◽  
Application Area ◽  
Fly Ashes ◽  
Ecological Problems

The fly ash as a byproduct of coal-fired power plants constitutes vital ecological problems. In Turkey, approximately 15 million tons ofashes are generated via the combustion of 40 million tons of lignite yearly. Worldwide, a number of investigation and applications wereundertaken to utilize fly ash in order to overcome the environmental problems. One of the application area of fly ashes is the production of building bricks. Characterization of fly ash samples from Seyitomer and Yatagan coal-firing power plants were conducted inthis study. TCLP 1311, ASTM3987-85 and EN 12457-2 leaching tests on the cylindrical fly ash/lime brick (FA/LB) samples which wereproduced from Seyitömer and Yatagan thermal power plant fly ash-lime mixtures were performed to determine the leachability ofsome chosen trace elements. The results show that the release of all trace elements was lower than the hazardous material limit valuesof waste acceptance. Thus, non- fired fly ash bricks are an advantageous way to solving environmental effect of disposal of fly ashes.

A Review on Utilization of Fly- Ash and Pond-Ash as a Partial Replacement of Cement in Concrete Mix Design

2018 ◽  
pp. 413-418
Author(s):  
Harshkumar Patel ◽  
Yogesh Patel
Keyword(s):  
Fly Ash ◽  
Electricity Generation ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Strength Test ◽  
Partial Replacement ◽  
Pond Ash ◽  
Research Activities ◽  
Ash Disposal

Now-a-days energy planners are aiming to increase the use of renewable energy sources and nuclear to meet the electricity generation. But till now coal-based power plants are the major source of electricity generation. Disadvantages of coal-based thermal power plants is disposal problem of fly ash and pond ash. It was earlier considered as a total waste and environmental hazard thus its use was limited, but now its useful properties have been known as raw material for various application in construction field. Fly ash from the thermal plants is available in large quantities in fine and coarse form. Fine fly ash is used in construction industry in some amount and coarse fly ash is subsequently disposed over land in slurry forms. In India around 180 MT fly is produced and only around 45% of that is being utilized in different sectors. Balance fly ash is being disposed over land. It needs one acre of land for ash disposal to produce 1MW electricity from coal. Fly ash and pond ash utilization helps to reduce the consumption of natural resources. The fly ash became available in coal based thermal power station in the year 1930 in USA. For its gainful utilization, scientist started research activities and in the year 1937, R.E. Davis and his associates at university of California published research details on use of fly ash in cement concrete. This research had laid foundation for its specification, testing & usages. This study reports the potential use of pond-ash and fly-ash as cement in concrete mixes. In this present study of concrete produced using fly ash, pond ash and OPC 53 grade will be carried. An attempt will be made to investigate characteristics of OPC concrete with combined fly ash and pond ash mixed concrete for Compressive Strength test, Split Tensile Strength test, Flexural Strength test and Durability tests. This paper deals with the review of literature for fly-ash and pond-ash as partial replacement of cement in concrete.

scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

scholarly journals Assessment of Characteristics of Acid Mine Drainage Treated with Fly Ash

2021 ◽  
Vol 11 (9) ◽  
pp. 3910
Author(s):  
Saba Shirin ◽  
Aarif Jamal ◽  
Christina Emmanouil ◽  
Akhilesh Kumar Yadav
Keyword(s):  
Fly Ash ◽  
Acid Mine Drainage ◽  
Power Plants ◽  
Mine Drainage ◽  
Thermal Power ◽  
Mineralogical Characterization ◽  
Acid Mine ◽  
Before And After ◽  
Abandoned Coal Mines

Acid mine drainage (AMD) occurs naturally in abandoned coal mines, and it contains hazardous toxic elements in varying concentrations. In the present research, AMD samples collected from an abandoned mine were treated with fly ash samples from four thermal power plants in Singrauli Coalfield in the proximate area, at optimized concentrations. The AMD samples were analyzed for physicochemical parameters and metal content before and after fly ash treatment. Morphological, geochemical and mineralogical characterization of the fly ash was performed using SEM, XRF and XRD. This laboratory-scale investigation indicated that fly ash had appreciable neutralization potential, increasing AMD pH and decreasing elemental and sulfate concentrations. Therefore, fly ash may be effectively used for AMD neutralization, and its suitability for the management of coalfield AMD pits should be assessed further.

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