Effect of Biomass Fly Ash on Fresh and Hardened Properties of High Volume Fly Ash Mortars

The objective of this work was to assess the use of biomass fly ash (BFA) as cement replacement material or as an alkalinity source in high volume fly ash mortar and concrete. Mortar formulations were prepared with different types of cement replacement: fly ash from thermal power plants, BFA, a blend of two pozzolans, and small amounts of BFA or/and hydrated lime (HL). Mortar formulations were tested both in the fresh and hardened state. The replacement of cement by the two fly ashes led to a decrease in the mechanical strength. The best strength values were obtained when higher HL content was introduced in mortars, however, mortars with the lower BFA content presented the best results for the majority of the tests. In general, BFA has a similar effect on cementitious mortars to coal fly ash, having good performance as cement replacement.

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Very high volume fly ash green concrete for applications in India

Waste Management & Research ◽

10.1177/0734242x18770241 ◽

2018 ◽

Vol 36 (6) ◽

pp. 520-526 ◽

Cited By ~ 11

Author(s):

Jing Yu ◽

Dhanada K Mishra ◽

Chang Wu ◽

Christopher KY Leung

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Power Plants ◽

Thermal Power ◽

High Volume ◽

Practical Method ◽

Green Concrete ◽

High Volume Fly Ash ◽

Binder Ratio ◽

Target Characteristic

Safe disposal of fly ash generated by coal-based thermal power plants continues to pose significant challenges around the world and in India in particular. Green structural concrete with 80% cement replaced by local Chinese fly ash has been recently developed to achieve a target characteristic compressive strength of 45 MPa. Such green concrete mixes are not only cheaper in cost, but also embody lower energy and carbon footprint, compared with conventional mixes. This study aims to adopt such materials using no less than 80% fly ash as binder in routine concrete works in countries like India with the commonly used lower target characteristic compressive strength of 30 MPa. It is achieved by the simple and practical method of adjusting the water/binder ratio and/or superplasticiser dosage. The proposed green concrete shows encouraging mechanical properties at 7 days and 28 days, as well as much lower material cost and environmental impact compared with commercial Grade 30 concrete. This technology can play an important role in meeting the huge infrastructure demands in India in a sustainable manner.

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Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽

10.3390/ma14051267 ◽

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.

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Development of High Volume Fly Ash Concrete Incorporating Steel Fibre

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b3567.079220 ◽

2020 ◽

Vol 9 (2) ◽

pp. 426-433

Keyword(s):

Fly Ash ◽

Aspect Ratio ◽

Thermal Power ◽

High Volume ◽

Fine Aggregate ◽

Fly Ash Concrete ◽

High Volume Fly Ash ◽

Hardened Properties ◽

Very High ◽

Split Tensile Test

Concrete is most frequently used composite material. Concrete is homogeneous mix of fine aggregate, Coarse aggregate and binding medium of concrete paste .Due to `high demand of cement Co2 emission is very high, It leads to global warming. So in this project high volume fly ash concrete was incorporated. Fly ash is the waste material obtained from thermal power plant. In this paper we investigated about high volume fly ash in different percentage of replacement 55, 60, 75 percentage. Layered pavement is incorporated with Steel fiber in a different aspect ratio (15, 30, 40).layered pavement will give good thermal expansive properties. By varying fly ash content and Steel fibers Aspect ratio of different mixes were arrived hardened properties of these nine mixes were arrived such as Compression test, Split tensile test and Flexural test.

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Composition and Morphology Characteristics of Magnetic Fractions of Coal Fly Ash Wastes Processed in High-Temperature Exposure in Thermal Power Plants

Applied Sciences ◽

10.3390/app9091964 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1964 ◽

Cited By ~ 3

Author(s):

Dinh-Hieu Vu ◽

Hoang-Bac Bui ◽

Bahareh Kalantar ◽

Xuan-Nam Bui ◽

Dinh-An Nguyen ◽

...

Keyword(s):

Fly Ash ◽

Power Plants ◽

Coal Fly Ash ◽

Thermal Power ◽

Combustion Process ◽

Mineralogical Composition ◽

Striking Difference ◽

Thermal Power Plants ◽

Power Stations ◽

Magnetic Components

Coal-fired power stations are one of the primary sources of power generation in the world. This will produce considerable amounts of fly ash from these power stations each year. To highlight the potential environmental hazards of these materials, this study is carried out to evaluate the characterization of fly ashes produced in thermal power plants in northern Vietnam. Fly ash was firstly fractionated according to size, and the fractions were characterized. Then, each of these fractions was analyzed with regard to their mineralogical features, morphological and physicochemical properties. The analytical results indicate a striking difference in terms of the characteristics of particles. It was found that magnetic fractions are composed of magnetite hematite and, to a lower rate, mullite, and quartz. Chemical analyses indicate that the non-magnetic components mainly consist of quartz and mullite as their primary mineral phases. As the main conclusion of this research, it is found that the magnetic and non-magnetic components differ in terms of shape, carbon content and mineralogical composition. In addition, it was found that magnetic components can be characterized as more spheroidal components compared to non-magnetic ones. This comprehensive characterization not only offers a certain guideline regarding the uses of different ash fractions but it will also provide valuable information on this common combustion process.

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Coal Fly Ash Ceramics: Preparation, Characterization, and Use in the Hydrolysis of Sucrose

The Scientific World JOURNAL ◽

10.1155/2014/154651 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 11

Author(s):

Ricardo Pires dos Santos ◽

Jorge Martins ◽

Carlos Gadelha ◽

Benildo Cavada ◽

Alessandro Victor Albertini ◽

...

Keyword(s):

Fly Ash ◽

Surface Area ◽

Power Plants ◽

Coal Fly Ash ◽

Thermal Power ◽

Coal Ash ◽

Mineralogical Composition ◽

Degree Of Hydrolysis ◽

High Degree ◽

Hydrolysis Of

Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several compaction pressures (63.66–318.30 MPa) and sintered at 1200°C for 4 h. Mineralogical composition (by X-ray diffraction) and surface area were studied. The ceramic prepared with 318.30 MPa presented the highest surface area (35 m2/g) and amount of immobilized enzyme per g of support (76.6 mg/g). In assays involving sucrose inversion, it showed a high degree of hydrolysis (around 81%) even after nine reuses and 30 days’ storage. Therefore, coal fly ash ceramics were demonstrated to be a promising biotechnological alternative as an immobilization support for the hydrolysis of sucrose.

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Optimization and Development of High-Strength High-Volume Fly Ash Concrete Mixes

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.c5927.098319 ◽

2019 ◽

Vol 8 (3) ◽

pp. 5289-5293 ◽

Cited By ~ 1

Keyword(s):

Fly Ash ◽

Activity Index ◽

High Strength ◽

High Volume ◽

Past Research ◽

Fly Ashes ◽

Hydraulic Lime ◽

Cement Replacement ◽

Fly Ash Concrete ◽

High Volume Fly Ash

Cement is the most abundantly used ingredient in the production of concrete due to which its production and use has increased manifold. To reduce the carbon footprint left by the cement production, fly ash is used as cement replacement in concrete. Past research studies suggest that the fly ash replacement can be upto 40% beyond which there will be drastic reduction of strength. In the present study, high strength concrete mix of 70 grade is developed with high volume fly ash of 70% as cement replacement. Silica fume of 10% and hydraulic lime of 30% are used as additives in the development of M70 grade high-strength high-volume fly ash concrete. In the present paper, three types of fly ashes are considered for the study of which one which is ultrafine is chosen based on the pozzolanic index and strength activity index. Excess lime needed for various percentage of fly ashes is evaluated based on the empirical equationsgiven by the Dunstan Jr andZayed

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CONVERSION OF COAL FLY ASH TO ZEOLITE-BASED IRON OXIDE MAGNETIC NANOCOPOSITES BY MODIFIED FUSION-HYDROTHERMAL SYNTHESIS

10.32006/eeep.2020.1.3035 ◽

2020 ◽

pp. 30-35

Author(s):

Silviya Boycheva ◽

Denitza Zgureva

Keyword(s):

Magnetic Properties ◽

Iron Oxide ◽

Fly Ash ◽

Power Plants ◽

Coal Fly Ash ◽

Thermal Power ◽

Coal Ash ◽

Low Temperature Processing ◽

Oxide Phases ◽

Stage Synthesis

Coal fly ash generated in Thermal Power Plants is utilized for synthesis of zeolites due to its aluminosilicate composition. The highest degree of zeolitization of coal ash in a particular zeolite phase is achieved by double-stage synthesis involving successive alkaline melting and hydrothermal activation of the reaction mixtures, while the uniform distribution of the iron oxides transferred from the raw coal ash is ensured by ultrasonic treatment. However, the applied melting step results in the oxidation of the magnetic iron oxide phases to non-magnetic ones, which results in the loss of magnetic properties of the resulting materials. The present investigation focuses on an improved double- stage synthesis procedure by the addition of raw coal ash containing magnetite between high temperature and low temperature processing. In this way, the magnetic phase is retained in the final product and the magnetic properties of the zeolites are preserved, which is important for their application in the adsorption of pollutants from wastewater.

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High Volume Fly Ash Self Compacting Concrete with Lime and Silica Fume as Additives

E3S Web of Conferences ◽

10.1051/e3sconf/202018401109 ◽

2020 ◽

Vol 184 ◽

pp. 01109

Author(s):

C Chandana Priya ◽

M V Seshagiri Rao ◽

V Srinivasa Reddy ◽

S Shrihari

Keyword(s):

Fly Ash ◽

Calcium Hydroxide ◽

Silica Fume ◽

High Volume ◽

Hydrated Lime ◽

Pozzolanic Reaction ◽

Self Compacting Concrete ◽

Conventional Concrete ◽

High Volume Fly Ash ◽

Reactive Silica

SCC is expensive when compared with normal conventional concrete. Hence, it is desired to produce low cost SCC by replacing cement with higher percentages of fly ash, which is a no cost material and available in abundance. At the same time to achieve higher grade HVFASCC, micro silica which is otherwise condensed silica fume can also be used along with fly ash to enhance the strength properties of HVFASCC. By replacing fly ash in high volumes in the mix, high amount of pozzolanic material becomes available, majorly reactive silica, for which more calcium hydroxide is necessary for further pozzolanic reaction. As we are reducing cement quantity, the amount of calcium hydroxide available is reduced thus demanding external addition of hydrated lime which can be supplied as additive to cater to the need of calcium hydroxide required for reactive silica in fly ash.The present investigation aims to achieve strength for high volume fly ash self-compacting concrete. The replacement of cement with fly ash is made in 45%, 50%, 55%, 60%, 65% and 70% with 20% hydrated lime and 10% silica fume in one trial. In another trial, 30% hydrated lime and 10% silica fume is added with replacement of fly ash to cement varying in same percentages. The design mix is tested for workability and flowability and cubes are casted for compression strength test and tested at 28 day,, 56 day, and 90 day,.

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