Fly ash booklet for pdf federal highway administration. Journal of environmental quality abstract physical. There are changes in the properties of concretes, particularly in temp. Fly ash like soil contains trace concentrations of the following heavy metals. Astm standard specifications do not exist for wood fly ash. Fly ash properties, types, mechanism and uses the constructor. The chemical composition of fly ash depends upon the type of coal used and the methods used for. Fly ash is produced as a result of the combustion of coal in coalbased thermal power plants.
Structural lightweight concrete is normally classified by a minimum compressive strength that was jointly established by the astm specification c 330 for lightweight aggregates and the. Effect of fly ash on physical properties of concrete authors. The specific gravity of fly ash ranges from a low value. The physical and mechanical properties of fly ash concrete. M 2 1 department of mining engineering, national institute of technology, rourkela769008 india. Physical and chemical properties of the wood fly ash are given in tables 1 and 2, respectively.
As per astm, the fineness of the fly ash is to be checked in both dry n wet. A variety of tests were conducted, including rheological measurements, various leaching tests, compressive strength testing, specific surface area. Effect of hydration conditions on the physical properties. It is well known that class f fly ash has pozzolanic properties and class c fly ash has pozzolanic properties, as well as some cementitious properties. Fly ash particles are generally in spherical shape. Geotechnical properties of fly ash and its application on. In the united states, astm c 6181, standard specification for coal fly ash and raw or.
Interest in coal residue research has recently been increased with anticipated increased dependence on coal as a source of energy. Chemical composition of fly ash from power plant gacko component sio2 al2o3 fe2o3 cao mgo so3 lost of. The particle size distributions of sf and fa were measured with a malvern nanosizer zs3600 at. Samples were taken from hardened specimens after 28 days to reduce their size for. Updating physical and chemical characteristics of fly ash. The fly ash content was maintained at 10% in the prototype evaluation due to the high level of effort associated with prototypescale testing. The current study was an attempt to quantify the effects of fly ashes on the properties of pastes as a function. Physical and chemical properties of fly ashes affect their options for reuse. Chemical admixture the main purpose to used superplasticiser was to maintain the workability of concrete.
Physical and chemical properties of fly ash from coal. Some ashes also containing irregular or angular particles. Characterization of fly ash is needed to map and to ensure the quality of the cement produced. Fly ash fly ash from power plant gacko is used as mineral filler for mixtures of bituminous aggregate. Detailed chemical analyses and physicalproperty determinations of 12 channelcoal samples reported on wholecoal and laboratory ash basis indicate that the coals are mostly of high coking quality, low. A study on the effect of fly ash and rice husk ash on. Normal range of chemical composition for fly ash produced from different. Fly ash is produced by coalfired electric and steam generating plants.
The ash is composed of the fine particles that are driven out of the boiler with the flue gases, before. Abstract of the total solid waste generated in india, approximately 25% is residue from coal combustion. United states electric power utilities consume from 60 to 65% of the amount of coal produced. Currently, fly ash particles were characterized based upon fineness since the particle size distribution significantly affects the ashs reactivity jimenez and palomo 2003. They consist mostly of silicon dioxide sio2, aluminium oxide al2o3 and iron oxide fe2o3. Wood fly ash collected from a baghouse from a pulp mill in wisconsin was used. Evaluation of the physical and chemical properties of fly ash. Physical chemical and leaching properties of rolling mill. The chemical composition of fly ash is shown in table 3, and its main physicalmechanical properties in table 4. Fly ash is the pulverized fuel ash extracted from the fuel gases by any suitable process like cyclone separation or electrostatic precipitation. Pdf study on physical and chemical properties of fly ash from.
Fly ash particles are generally spherical in shape and range in size from 2. Five fly ash samples sourced from different power plants around australia were used to manufacture geopolymer binders, enabling investigation of the relationship between the physical and chemical properties of fly ash and the mechanical properties of geopolymer products. The physical and mechanical properties of fly ash concrete free download as powerpoint presentation. Table 1 lists ranges for some ofthe important geotechnical properties of fly ash and bottom ash. Modern coalquality data and geologic field observations are interpreted in terms of the coal geology in a small area near pocahontas, va. Use of fly ash for reconstruction of bituminous roads. Fly ash consists of inorganic, incombustible matter present in the coal that has been fused during combustion into a glassy, amorphous structure.
Moreover, geopolymers combined with loess and fully weathered granite were developed as useful building materials 29 31. Properties of fly ashextended asphalt concrete mixes. Fly ash or flue ash, also known as pulverised fuel ash in the united kingdom, is a coal combustion product that is composed of the particulates fine particles of burned fuel that are driven out of coalfired boilers together with the flue gases. In view of these superior properties, generating geopolymers by using alkaliactivated fly ash to improve the bearing capacity of foundation soil has been reported recently 27, 28. Physical, chemical, and geotechnical properties of coal fly ash. The silica fume sf and the f type fly ash fa were from eti krom inc. Scope of this study is to analyze the consequences of the application of fly ash in soft soil stabilization. Physical and mechanical properties of polymer composites. We energies coal combustion products utilization handbook. When incorporated in concrete mixtures, fly ashes are known to influence both its fresh and hardened properties.
The physical properties related to the agronomic use of fly ashamended soils were characterized by determining waterholding capacity, bulk density, hydraulic conductivity, and modulus of rupture on. In contrast, the properties of fly ash is not only determined by the physical. Many countries have their own national standards and specifications regulating the use of fly ash in concrete. Physical and chemical characterization of pond ash prasenjit ghosh and sudha goel civil engineering department, iit kharagpur, kharagpur 722, india. Fly ash mostly consists of silicon dioxide sio2, aluminium oxide al2o3 and iron oxide fe2o3. Compared to cement and water, the chemical reaction between fly ash and calcium hydroxide typically is slower resulting in delayed hardening of the concrete. Mechanical properties of tunnel muck with flyash geopolymer. The effects of the hydration conditions such as temperature, time, and fly ashcaoh 2 weight ratio on the physical properties of activated sorbents were investigated. Coal fly ash is a coal combustion product that has numerous. An accurate and quick technique to predict the extent of this influence based on the characteristics of fly ash would be highly beneficial in terms of field applications.
Scanning electron microscopy and energy dispersive xray spectroscopy were performed with a fei helios nanolab 400. As we specific surface area of rha is high and it needed more water. Properties of fly ash 16 properties of bottom ash 20 properties of boiler slag 23 properties of fgd gypsum 25 current we energies ccp sources 27 chapter 3 properties of we energies coal combustion 35 products physical, chemical and mechanical properties of fly ash 36 physical, chemical and mechanical properties of bottom ash 39. The properties of fly ash can greatly affect the properties for both fresh concrete and hardened concrete. Theyobserved that with the addition of flyash from 30% to 54% in epoxy resinflyash composite the compressive strength was found to increase with increase in fly ash content. Type f fly ash is produced from the combustion of bituminous or an anthracite coal contains cao below 10 percent and possesses pozzolanic properties. In general, the specific gravity of coal ashes lies around 2. Pdf fly ash is the finely divided mineral residue resulting from the combustion of coal in electric generating plants.
Updating physical and chemical characteristics of fly ash for use. For this purpose, fly ashcaoh 2 mixtures with different weight ratios were hydrated under different conditions. Rheological characteristics of fly ash slurry at varying. Fly ash used as a workability agent to provide mixes that can flow great distances without segregation. A statistical design technique was applied by use of twolevel. Above 300c, there is decrease in mechanical characteristics. They consist mostly of silicon dioxide sio2, aluminum oxide al2o3 and iron oxide fe2o3. 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. The nearest astm standard available is astm standard specification for coal fly ash and raw or. Characterization of fly ash and it effects on the compressive strength. Chemical analyses and physical properties of 12 coal. For characterization of the geopolymer, 50 mm cube specimens of paste were cast with a naoh to fly ash ratio of 0.
The objectives of the study are to determine the geotechnical properties of fly ash and to investigate the effects of fly ash addition for strength of stabilized soft soil. Pulverised fuel ash an overview sciencedirect topics. Fly ash from a coalfired power generating plant was mixed with five california soils at rates of 0, 2. The effect of high temperature on concrete containing ash or natural pozzolans has not been investigated very well.
They consist mostly of silicon dioxide sio 2, aluminium oxide al 2 o 3. Fly ash consists of fine, powdery particles predominantly spherical in shape, either solid or hollow, and mostly amorphous in nature. Influence of physical properties on engineering properties. All fly ashes exhibit cementitious properties to varying degrees depending on the chemical and physical properties of both the fly ash and cement. However, 10% is the common fly ash content used in practice.
Istanbul, tr and yatagan thermal plant yatagan, tr, respectively. Typically, coal is pulverized and blown with air into the boilers combustion chamber where it immediately ignites, generating heat and producing a molten mineral residue. Nine numbers of class f fly ash samples have been used in this investigation to study the suitability of using these materials for geotechnical construction. By virtue of its physical characteristics and sheer volumes generated, fly ash poses problems like. Physical property value colour whitish gray bulk density 1120 kgm3 specific gravity 2. Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete. In the present work physical, chemical and leaching properties of fly ash have been investigated. As shown in table 11, of the 62 million metric tons 68 million. Black, in sustainability of construction materials second edition, 2016. 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. Effect of fly ash on physical properties of concrete. Comparative study of the characteristics of nano silica. Physical properties of the fly ash used color whitish grey bulk density gcm30.
Characterization and early age physical properties of. First type in the form of day samples wercubes and second. Ash that falls to the bottom of the boilers combustion chamber commonly called a firebox is called bottom ash. Carbonation is a process in which carbon dioxide in air reacts with calcium hydroxide and sometimes calcium silicates and aluminates in hydrates cement and produce calcium carbonate. 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.
Effect of the alkali metal activator on the properties of. Fly ash is the finely divided mineral residue resulting from the combustion of coal in electric generating plants. Scribd is the worlds largest social reading and publishing site. The test results on physical properties table 2 and chemical composition table 1 of all the fly ash samples discussed are presented in this paper.
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