Modeling the Effects of Fly Ash Characteristics and Mixture Proportions on Strength and Durability of Concretes

1986 ◽  
Vol 86 ◽  
Author(s):  
Elizabeth L. White ◽  
Della M. Roy ◽  
Philip D. Cady
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Common Factor ◽  
Load Condition ◽  
High Water ◽  
The United States ◽  
Type I ◽  
Modeling Tools ◽  
Strength Factor ◽  
Sulfate Resistance

ABSTRACTFactor analyses and cluster analyses were the modeling tools used to relate the chemical and physical characteristics of fly ash and cement to the strength, sulfate resistance, and freeze-thaw durability of fly ash-modified concrete. A Type I Portland cement was mixed with base load and upset load condition fly ashes from three different power plants in each of five regions in the United States. Based on the interactions between the reactive constittuents of the cement and fly ash, common factor loadings were identified. Cement loaded onto the early strength factor; fly ash loaded onto the later strength factor. In some subgroups the quantity of mixing liquid loaded separately as representative of the high water/cement ratio, which masked the reactive interactions between the fly ash and cement. In other subgroups the inter-relationships between sulfate resistance and strength with fly ash/cemment fineness, CaO content, and alkali content were represented in the factor analysis as well as in the numerical analysis models.

Water Use Management Challenges in Power Generation

2013 ◽  
Author(s):  
Kit Y. Ng ◽  
Ping K. Wan
Keyword(s):  
Power Generation ◽  
Water Use ◽  
Site Selection ◽  
Power Plants ◽  
Management Strategies ◽  
Cooling Water ◽  
The United States ◽  
Modeling Tools ◽  
Planning Stage ◽  
Term Operation

Shrinking fresh water resources and increasing competing demands for water among other users have been a growing concern in many parts of the world, which compels the challenges in water use management faced by both operating and new power generation facilities. For new plants in the planning stage, the ability to demonstrate the availability of water and develop practical and achievable water use management strategies to support the long-term operation of the proposed facility in a sustainable manner has become one of the key elements in the site selection process. The water demands of particular concerns for the power industry come primarily from cooling water needs, which traditionally constitute the majority of plant water use during the operation phase. This paper examines the water use management challenges confronted by new nuclear power plants in site selection and licensing stages as well as by existing plants in the operating stage in the United States. Using an example, it discusses the types of adaptive approaches on the selection of the heat dissipation systems and designs of cooling water systems that can be adopted by new plants to mitigate the declining water availability, and the related environmental and regulatory challenges. The use of modeling tools to estimate cooling water consumptions and availability and predict environmental impacts in the development of sustainable water management strategies are also illustrated.

scholarly journals Exploring The Use of Cognitive Models for Nuclear Power Plant Human-System Interface Evaluation

2019 ◽  
Vol 63 (1) ◽  
pp. 2190-2194
Author(s):  
Casey R. Kovesdi ◽  
Jeffrey C. Joe
Keyword(s):  
Cognitive Modeling ◽  
Quantitative Data ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Critical Role ◽  
The United States ◽  
Cognitive Models ◽  
Modeling Tools ◽  
Human System

Many of the United States’ commercial fleet of nuclear power plants (NPPs) are approaching the end of their operating licenses. To extend the life of these plants, advanced human-system interface (HSI) technologies are being researched to address aging and reliability concerns with existing legacy systems. Human factors engineering (HFE) a critical role in ensuring these technologies are designed in a way that does not introduce new failure modes and promotes optimal human-system performance. An important focus of HFE in NPP modernization is early involvement to inform design of the HSI. This includes traditional formative evaluations, which are done to collect design feedback. While these evaluations are useful, they are limited in providing convincing quantitative data for efficiency of use. This paper discusses the use of cognitive models to provide quantitative data early in the HSI design process. A comparison is made of three open-source and readily accessible cognitive modeling tools.

Use of Hydrated Fly Ash as a Flexible Base Material

1996 ◽  
Vol 1546 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Sanjaya P. Senadheera ◽  
Priyantha W. Jayawickrama ◽  
A. S. M. Ashek Rana
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Soil Stabilization ◽  
Base Material ◽  
The United States ◽  
Curing Conditions ◽  
Texas Department ◽  
High Calcium ◽  
Flexible Base ◽  
Class C

Common uses for fly ash, such as soil stabilization and cement replacement, account for less than 20 percent of the fly ash produced in the United States. Therefore, finding other bulk uses for fly ash is important. One such potential application is hydrated fly ash as a base material. The Texas Department of Transportation (TxDOT) is working to produce specifications to incorporate hydrated fly ash as a flexible base material. High-calcium Class C fly ash has a self-hydrating capability in the presence of moisture. Class C fly ash produced from coal power plants using lignite and subbituminous coal is mixed with water, dumped in large pits, and left to hydrate for a period of 3 to 6 weeks. The result is a hard, homogeneous mass of hydrated fly ash that can be mined to produce a construction aggregate much like limestone. TxDOT has used this material on several test projects. It has a desirable compressive strength, but in some instances its adhesion to seal coats has been a problem. Laboratory studies indicate that hydration water content has a significant influence on its strength. Microscopic investigations on hydrated Class C fly ash indicate that the hydration products may depend on the curing conditions. Hydrated Class C fly ash has a potential as a flexible base material provided that the curing process is carefully managed.

A Comparison of Several Sample Preparation Techniques for the Analysis of Fly Ash

1986 ◽  
Vol 30 ◽  
pp. 251-256
Author(s):  
Scott Schlorholtz ◽  
Turgut Demirel
Keyword(s):  
United States ◽  
Fly Ash ◽  
Power Plants ◽  
Fossil Fuel ◽  
The United States ◽  
Particulate Material ◽  
Flue Gases ◽  
Environmentally Safe ◽  
Preparation Techniques ◽  
Disposal Problem

Fly ash is a finely divided particulate material that is removed from the flue gases of pulverized coal burning power plants. Recent emphasis on the utilization of fossil fuel (i.e., coal) has created a serious waste disposal problem in that, of the 60 million tons of fly ash produced annually in the United States, only about 20% is being utilized [1], The remaining fly ash (about 48 million tons per year) must be disposed of in some environmentally safe manner.

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.

UTILIZATION OF COAL FLY ASH FROM POWER PLANTS - I. ASH CHARACTERIZATION

2008 ◽  
Vol 7 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Maria Harja ◽  
Marinela Barbuta ◽  
Lacramioara Rusu ◽  
Nicolae Apostolescu
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

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.

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