Properties and use of coal fly ash pdf

Physical, chemical, and geotechnical properties of coal fly. Properties of concrete containing ultrafine fly ash. Coal fly ash material description user guidelines for. Fly ash normally produced from lignite or subbituminous coal that meets the applicable requirements for this.

You may need a pdf reader to view some of the files on this page. Pdf analysis on characteristics of fly ash from coal fired. The chemical properties of fly ash are influenced to a great extent by those of the coal burned and the techniques used for handling and storage. Pdf analysis on characteristics of fly ash from coal. Material designation % fly ash by weight compressive strength nmm2 c1 30 84. Geotechnical properties of fly ash and soil mixtures for use. Introduction according to the american coal ash association, in 2007, the united states produced. Analysis on characteristics of fly ash from coal fired power stations article pdf available in energy procedia 17. Optimizing the use of fly ash in concrete portland cement. Strength fly ash can increase strength strength gain happens slower with a pozzolanic class f vs. Fly ash is also used as a component in the production of flowable fill. Coal combustion residual beneficial use evaluation.

Therefore it is crucial to details the characteristics and properties of fly ash, prior to use fly ash particles in any application. During the burning process of coal for the electricity generation, coal waste is produced which includes coal ash in the fraction of about 7585 % fly ash fa and 1525 % bottom ash ba. The chemical composition of fly ash depends upon the type of coal used and the methods used for combustion of coal. The properties of fly ash and bottom ash make them useful for a variety of construction applica tions. When mixed with lime and water, fly ash forms a compound similar to portland cement. Coal combustion residual beneficial use evaluation report. Physical, chemical, and geotechnical properties of coal fly ash. Coal fly ash is composed principally of sio2 45% and al2o3 35% and in most cases is highly basic ph 12 it usually also contains significant quantities of calcium and a variety of elements at trace. The use of fly ash as a pozzolanic ingredient was recognized as early as 1914, although the earliest noteworthy study of its use was in 1937. Several studiesassessing the environmental impactofcoal fly ash have. The role of fly ash in asphalt concrete mixes has been investigated. Introduction fly ash is finely divided residue resulting from the combustion of coal. The effect of mixing ratio and compaction water content on the geotechnical properties of fly ash soil mixtures was discussed.

Since fly ash shows a wide range of physical and chemical properties. The most widely used specification for fly ash in north america is astm c618 standard specification for coal fly ash and raw or. Properties and use of coal fly ash ice virtual library. Evaluation of the physical and chemical properties of fly ash. Pdf overview of different type of fly ash and their use as a building. Coal fly ash used as a direct substitute for portland cement in concrete hereafter referred to as fly ash concrete and fgd gypsum used as a replacement for mined gypsum in wallboard hereafter. In other word, the burning of harder, older anthracite and bituminous coal typically produces class f fly ash. There are basically four types, or ranks, of coal, each of which varies in terms of its heating value, its chemical composition, ash content, and geological origin. Chemical and toxicological properties of coal fly ash. Physical and chemical properties of fly ashes affect their options for reuse.

Coal rank is an indication of how much transformation the orig inal plant material has under gone. A pozzolan is a siliceousaluminous material that, when mixed with lime and water, forms a cementitious compound. Activated coal fly ash and improvement of their mechanical. Characteristics, management and environmental issues. This book draws together a large quantity of research that has been carried out on pulverised fuel ash pfa over the past 30 years. The burning conditions within a power plant can also affect the properties of the fly ash. Class c type fly ash normally produced by burning lignite or sub bituminous coal. Fly ash concrete and fgd gypsum wallboard pdf 91 pp, 1 mb, february 2014, epa530r1400. Class f fly ash is usually produced by burning anthracite or bituminous coal, while class c fly ash is normally produced by burning subbituminous coal or lignite. Benefits and risks of the agricultural uses of coal fly ash. In the united states, astm c 6181, standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete, is the common specification to assess the suitability of fly ash and pozzolan for use in concrete. Use of fly ash for reconstruction of bituminous roads.

The specific properties depend on the type of coal used, the combustion conditions, and the collector setup, among other factors. Pdf the tremendous improvement in the civilization and industrialization. Fly ash properties and uses monolithic dome institute. Since the first edition of fly ash facts for highway engineers in 1986, the use of fly ash in highway construction has increased and new applications have been developed.

Fly ash properties, types, mechanism and uses the constructor. Fly ash consists of inorganic, incombustible matter present in the coal that has been fused during combustion into a glassy, amorphous structure. Production of geopolymer binder from coal fly ash to make cementless concrete hydration mechanism and strength of opc and blended opc with fly ash in the presence of metakaolin the production, disposal, and beneficial use of coal combustion products in florida. It is nowadays used in cement, concrete and other cement based applications in india. Fresh propertiesthat is, slump, water demand, and set timeand hardened propertiesthat is, shrinkage and compressive strength of concrete containing sf. Coal fly ash is a coal combustion product that has numerous applications in highway construction. The chemical and physical properties of a particular uffa are reported herein. The purpose of this study was to develop a practical method to design local roadways using stabilized rpm or srsg as the base. Fly ash, a byproduct of the coal burning process for power generation, is a filler that can serve one or more of the abovementioned functions. Three sizes of fly ash coarse, medium, and fine were used. Those cements were made near the small italian town of pozzuoli which later gave its name to the term pozzolan.

The fly ash produced from the burning of pulverized coal in a coal fired boiler is a finegrained, powdery particulate material that is carried off in the flue gas and usually collected from the flue gas by means of electrostatic precipitators, baghouses, or mechanical collection devices such as cyclones. Effective use of coal ash as ground materials in japan. Roman structures such as aqueducts or the pantheon in rome used volcanic ash or pozzolana which possesses similar properties to fly ash as pozzolan in their concrete. Fly ash is a fine powder that is a byproduct of burning pulverized coal in electric generation power plants. Moreover fly ash properties depend upon the origin of the fuel and parameters used during the combustion process. Sources of fly ash and it use in construction industry astm broadly classifies two classes of fly ash i. Typical ranges for geotechnical properties of fly ash and bottom ash. Fly ash is a pozzolan, a substance containing aluminous and siliceous material that forms cement in the presence of water. Using a fly ash pozzolan consumes calcium hydroxide ch. Versailles, ky 8598730188 introduction the powder river coal is classified as sub bituminous ranked coal. Beneficial reuse of coal ash from dominion energy coal ash. Because coal fly ash is the primary constituent of the ash ponds that are the subject of this report and is a material with a high economic value when replacing portland cement in concrete mixtures, it is used as an additional term in this report to refer specifically to that material. High ash content 30% 50% coal contributes to these large volumes of fly ash. Type c fly ash is produced from the combustion of lignite or sub bituminous coals, contains cao higher than 10 percent and possesses cementitious properties in addition to pozzolanic properties.

May, 2014 class f fly ash has pozzolanic properties only. Concrete made with coal fly ash is stronger and more durable than concrete made with cement alone. Understanding the physical, chemical and mineralogical properties of coal fly ash is important, as these properties influence its subsequent use and disposal. The physicalchemical properties of fly ash depend not only on the type of coal used in a process but also on the techniques used to burn the coal.

This fly ash is pozzolanic in nature, and contains less than 20% lime cao. The main basic characteristics of the coal fly ash mixed material are as follows. Coal combustion products, fly ash utilization, properties of concrete. Table 1 lists ranges for some ofthe important geotechnical properties of fly ash and bottom ash. Type f fly ash is produced from the combustion of bituminous or an anthracite coal contains cao below 10 percent and possesses pozzolanic properties. Over 70% of waste coal ash is categorized as fly ash fa, fine particulates.

Comparison of compressive strength using different wt. Fuel ash and fly ash are produced as waste from burining coal or waste materials and have many uses within the construction industry such as in concrete land reclamation, treating oil and sewage wastes, bricks and blocks and grouting voids in the ground. Characterization for coal fly ash after mechanical activation the chemical composition of coal. Geotechnical properties of fly ash and soil mixtures for. Properties of fly ashextended asphalt concrete mixes. The quantity of fly ash is growing along with the steady global increase in coal use. Mechanical properties of epoxy resin fly ash composite. Fly ash reacts with the hydrating hydraulic cement to form a. Air pollution control technologies scrubbers, selective catalytic reduction, and. Uses, benefits, and drawbacks of fly ash in construction. Fly ash closely resembles volcanic ashes used in production of the earliest known hydraulic cements about 2,300 years ago. Roads, bridges, buildings, concrete blocks and other concrete products commonly contain fly ash. Because it improves many desirable properties of concrete, it is introduced either as a separately batched material or as a component of blended cement. Fly ash is a byproduct from the combustion of pulverized coal, and is widely used as an ingredient in hydrauliccement concrete.