The Multifaceted Applications of Fly Ash: A Review

The use of fly ash as a filler in cement to increase its strength is a viable option, providing a positive environmental impact by reducing the amount of cement used and minimizing land and groundwater contamination. Fly ash can also be used as a fertilizer, making it a valuable resource for sustainable development.

Running head: THE CONTENTS OF FLY ASH AND ITS USES
The Contents of Fly Ash and Its Uses
Name of the Student
Name of the University
Author Note

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THE CONTENTS OF FLY ASH AND ITS USES
Abstract
The result of combustion of coal is termed as fly ash or pulverized fuel ash. It is made up of
minute particles and is driven out of the boilers of the thermal power plant. It is collected by
proper filtering methods. The main contents fly ash is aluminum and siliceous material that is
capable of forming cement in presence of water. The report elaborates the contents and uses of
fly ash as an additional cement type material for production of Portland concrete cement. Fly ash
can be considered as a partial replacement of Portland cement, which is mainly used in
producing concrete. The literature review and the detailed analysis of component and use of fly
ash are elaborated in this report.

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THE CONTENTS OF FLY ASH AND ITS USES
Table of Contents
1.0 Introduction....................................................................................................................3
2.0 Literature Review..........................................................................................................3
3.0 Evaluation......................................................................................................................7
4.0 Conclusion.....................................................................................................................9
5.0 References....................................................................................................................11

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THE CONTENTS OF FLY ASH AND ITS USES
1.0 Introduction
By product of burning pulverized coal in power plant that generates electric, is known as
fly ash. This product can be used as an additional and supplementary form of Portland cement.
Fly ash is formed by the fusion of the impurities present in coal, which includes clay, feldspar,
quartz and shale. The mineral impurities that are present in the coal fuse in suspension due to the
excessive heat generated as a result of Combustion. However, on rising up, these fused materials
cools down and solidifies to become a spherical glassy particle, which is known as fly ash.
Electrostatic precipitators is used in collection and filtration of the fly ash that is collected from
the exhaust gases (Anastasiou, Filikas and Stefanidou, 2014). Fly ash can be used instead of of
Portland cement as it reacts with the byproduct of the reaction between water and cement,
helping in improving the desirable features of concrete. However, the chemical reaction that
takes place between fly ask and calcium hydroxide is much slower as compared to the cement
and water. Therefore, the process of hardening of the concrete is also delayed. Moreover, the
variable properties of fly ash can create certain challenges for producer and finisher in different
projects. The detailed literature review and the different uses of fly ashes are elaborated in the
following paragraphs-
2.0 Literature Review
According to Thomas (2013), fly ash can be considered as a supplementary cement
material for the development of Portland cement concrete. It contributes to the features of
hardened concrete through hydraulic activity. It is basically a siliceous and aluminous material
that has cement like value and is capable of reacting chemically with calcium hydroxide in

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THE CONTENTS OF FLY ASH AND ITS USES
ordinary temperature. The potential of fly ash is known since the start of last century but has seen
significant utilization only in mid 1900s. the use of fly ash has increased to a great extent in the
past years and is now being close to 15 million tons. The problem can be experienced with the
extended set times and the slower development of strength. The fly ash is end-product or by
product of the pulverized coal due to combustion and is collected by mechanical separators. The
different components of fly ash include amorphous alumina silicate along with different amount
of calcium.
According to Blissett and Rowson (2012), the utilization of fly ash, which is an end
product of industrial process, has received a wide attention over the past years. The different
application of coal gas includes using is as raw material for manufacturing glass and ceramics,
production of Zeolites and so on. Therefore, potential use of fly ash is significant in both raw
and refined state.
Major power stations use fly ash and as a result, a huge amount of fly ash is obtained as a
byproduct of combustion of coal. Therefore, different strategies are to be developed in order to
ensure the consumption of fly ash in a bulk amount. (Pandian 2013.) The author illustrates the
use of fly ash in different geotechnical applications.
According to Yao et al. (2015), fly ash is used in different sectors such as, soil
amelioration, construction industry, and ceramic industry apart from depth separation and zeolite
synthesis. Fly ash is therefore considered as a replacement of Portland cement but it is an
expensive replacement. However, considerable and measured use of fly ash improves the power,
strength, segregation and ease of pumping the concrete. Fly ash can be used in paving or bricks,
apart from using an application of PCC pavement.

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THE CONTENTS OF FLY ASH AND ITS USES
According to Franus (2012), fly ash has an extensive use in preparation of Zeolite. The
fly ash might have a negative effect in environment and human health. For transforming the fly
ash into Zeolites, all the synthesis conditions are analyzed, which includes the time and
temperature of the reactions.
According to Zermeno et al. (2013), fly ash can be significantly used as a secondary
building material for maximizing the use of APC fly ash. This can considerably reduces the
damages and the negative effect that can originate from combustion. However, due to the use of
the modern pollution control equipments, this fly ash is collected using the electrostatic
precipitators and other particle filters. Fly ash consists of sio2, Al2O3 and Fe2o3 as its chemical
composition. It also consists of trace amount of arsenic, beryllium, cadmium, chromium, cobalt,
nickel, mercury, molybdenum, selenium and strontium.
Estevel et al. (2012) researched about the process and effect of the mitigation of alkali
silica reaction that takes place in the cement paste and reactive siliceous combines with fly ash.
The different researches prove that, biomass fly ashes can replace the cement by 20% to 30%.
Gesoglu et al. 2012, discussed the major concerns in disposal and recycling of the waste
materials. The use of fly ash as marble powder, limestone filler as a constituent of self-
compacting cement, considerably helps in improving the viscosity and flowability of those type
of cement. Use of fly ash as a replacement of cement helps in improving and enhancing the
durability and permeability properties with the incorporation of fillers.
Sarker, Haque and Ramgolam, (2013), discussed that with the increasing demand of
cement, fly ash can be a great alternative that can be used in place of cement. Moreover, the use
of fly ash as an alternative binder in place of cement can help in reducing the co2 emission. This

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THE CONTENTS OF FLY ASH AND ITS USES
is however, very different from the ordinary Portland cement both in composition and structure.
Hence, it becomes essential to study the result of geo polymer binder on concrete. One of the
major component of geo-polymer binder is fly ash, which is blended with blast furnace slag and
rice husk ask in development of the geo-polymer binder. The fly ash that is generated in all coal-
fired power stations can be efficiently used in geo-polymer concrete, that considerably help in
reduction of carbon foot print.
Kumar and Kumar (2013) discussed the use of a mixture of red mud and fly ash in
ambient temperature geo-polymerization. Red mud is a byproduct generated as a result of
Bayer’s process and by product of burning of coal is termed as fly ash. Use of these two by
products can considerably reduce the negative effect it cast on environment and human
health.For developing alumina silicate polymers in alkaline environment, geo polymer is used.
The main component of fly ash includes Sio2 and Al2o3 and that of red mud consists of Fe2o3,
Sio2 and Al2O3. Therefore, a mixture of these two components can be most effectively used in
geo-polymerization.
Ukwattage, Rahnith and Bouazza (2013) discusses that fly ash can be effectively used as
a soil amendment in cultivation land. One of the major and problematic solid wastes include fly
ash that is generated as a byproduct in process of generation of electricity. The large amount of
fly waste that is disposed in arable lands that result in degradation, contamination and wastage of
land and ground water. Fly ash can therefore be used as a useful soil ameliorant as it has some
properties that are capable of enhancing the fertility and productivity of the soil. Fly ash can be
productively used in improving the physical, chemical as well as biological properties of soil. Fly
ash is readily available micronutrients and macro nutrients of plants and can be considerably
used in countries that have structural and nutritional limitations in soil. This is because; fly ash

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creates different probable solution for improving the yields of crops and enhancing the food
security. Furthermore, fly ash finds its use in terrestrial carbon sequestration apart from
improving the microclimate of the soil, which facilitates the organic matter of humification in
yielding stable form of soil carbon. Ukwattage, Rahnith and Bouazza (2013) thus propose the
use of fly ash in improving the productivity of the soil by using it in the cultivable land.
Cuenca et al. (2013) discusses the contribution of pulverized fuel ash or fly ash in
reducing the amount of super plasticizer in manufacturing of concrete with standard properties.
The authors laid forward the idea of using fly ash as a partial substitute for cement and fly ash as
a filler for self compacting concrete. Fly ash has its use in manufacturing the self-compacting
material or concrete as a total replacement of convectional filler. The use of self compacting
concrete helps in reducing the construction time, cost of labor and enhancement of
constructability facilities.
Berra, Mangialardi and Paolini (2015) further discusses that it is possible to reuse bio
mass fly ash in form of mineral admixture and partial sand filler in cement based materials and
mixtures. Various researches prove that the use of fly as a cement filler can be used as a sand
filler material as it gives satisfactory but low quality concrete.
Giron et al. (2013) discusses the extensive use of fly ash as activated carbon, Zeolite
cement. Different fly ash has different chemical composition and shows varied usage.
Ryu et al. (2013) laid forward the idea behind the use of fly ash for building alkali-
activated concrete. It further elaborates the effects of chemical changes due to different alkaline
activators on comprehensive strengths of mortar.
3.0 Evaluation

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Examining the different data obtained from the literature review in the previous section, it
can be said that fly ash has varied uses in different fields, the most prominent being the use of fly
ash as an alternative or filler for cement. Extensive accumulation of fly ash has negative effects
on health of human and environment and therefore, different processes and researches are being
carried out for making the use of fly ash. Apart from filler as cement, fly ash has an extensive
use in increasing the fertility of the soil. Thus, it can be used in soil ameliorant and has different
properties in enhancing the fertility of the soil. Moreover, the accumulation of fly ash has
dangerous effects on the environment and therefore, the use of it in amendment of soil fertility is
increasingly useful. Moreover, as an alternative or replacement of Portland cement, fly ash has
the capability of increasing the strength, segregation and pumping of the concrete. Fly ash can be
generally used as prime materials in blocks. Furthermore, use of fly ash provides significant
economic benefits as well. However, one of the major concerns in using fly ash as a filler for
concrete includes slower strength gain, seasonal limitation and increase in salt scaling.
Moreover, the use of fly ash in different project can further help in reducing the co2 emission
thus helping reducing the pollution and environmental damage.
From the major clues obtained from the literature review and going through its success
stories, it can be deduced that the major use of fly ash can be in form of a filler of Portland
cement. The component of fly ash is appropriate enough to use as a filler for cement (Singh and
Gupta 2014). There are different type fly ashes that can be used in different sectors. The different
components of the fly ash includes arsenic, boron, cobalt lead and other such components that
can be increasingly used as a binding agent. Therefore, fly ash can definitely act as a filler for
cement. However, according to the data obtained from the extensive literature review, it is seen
that the setting time of such cement is long and this can be problem. This is because; using such

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THE CONTENTS OF FLY ASH AND ITS USES
cement may take a prolonged time in completing the building and construction works and
therefore, may not be used by many. These drawbacks can be eliminated with further researches
as the use of fly ash offers varied benefits. Moreover, the comprehensive strength offers by the
fly ash is effective enough and therefore the idea of using fly ash as a filler of cement can be
considered noteworthy. However, the use of fly ash may not replace the use of cement due to its
certain limitations but can definitely be used as its partial replacement. Other than this, the use of
fly ash considerably increases the crop yields by increasing the fertility of soil and therefore, it
can be seen helping in curing the environmental damages. The partial replacement of cement can
be carried out up to 40% by fly ash and should be mixed with cement for yielding an appropriate
result (Zhang et al. 2014). The use of fly ash considerably helps in increasing the strength of
concrete and therefore, is a feasible and useful solution of using the waste products obtained
from the thermal power plants. It will further help in lessening the environmental damages
caused due to the exposure of fly ash in environment and its accumulation in large amount.
4.0 Conclusion
Therefore, from the above discussion, it can be concluded that using fly ash in different
sectors are being on process for quite sometimes and different alternatives have been tried and
tested in this field as well. The most prominent use being as a filler for cement for increasing the
strength of the mixture. Apart from this, fly ash can be used as a fertilizer. Accumulation of fly
ash has extensive negative effects in the environment including land and ground water
contamination. The dispersion of fly ash in environment has negative effects in environment,
which is now prevented with the use of electrostatic precipitator. These electrostatic
precipitators, prevents the direct release of fly ash in the environment. Therefore, the strategic

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use of fly ash as an alternative or cement filler not only has a positive effect in environment, but
also helps in reducing the price of using cement in the concrete.

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THE CONTENTS OF FLY ASH AND ITS USES
5.0 References
Anastasiou, E., Filikas, K.G. and Stefanidou, M., 2014. Utilization of fine recycled aggregates in
concrete with fly ash and steel slag. Construction and Building Materials, 50, pp.154-161.
Berra, M., Mangialardi, T. and Paolini, A.E., 2015. Reuse of woody biomass fly ash in cement-
based materials. Construction and Building Materials, 76, pp.286-296.
Blissett, R.S. and Rowson, N.A., 2012. A review of the multi-component utilisation of coal fly
ash. Fuel, 97, pp.1-23.
Cuenca, J., Rodríguez, J., Martín-Morales, M., Sánchez-Roldán, Z. and Zamorano, M., 2013.
Effects of olive residue biomass fly ash as filler in self-compacting concrete. Construction and
Building Materials, 40, pp.702-709.
del Valle-Zermeño, R., Formosa, J., Chimenos, J.M., Martínez, M. and Fernández, A.I., 2013.
Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary
building material. Waste management, 33(3), pp.621-627.
Esteves, T.C., Rajamma, R., Soares, D., Silva, A.S., Ferreira, V.M. and Labrincha, J.A., 2012.
Use of biomass fly ash for mitigation of alkali-silica reaction of cement mortars. Construction
and Building Materials, 26(1), pp.687-693.
Franus, W., 2012. Characterization of X-type Zeolite Prepared from Coal Fly Ash. Polish Journal
of Environmental Studies, 21(2).
Gesoğlu, M., Güneyisi, E., Kocabağ, M.E., Bayram, V. and Mermerdaş, K., 2012. Fresh and
hardened characteristics of self compacting concretes made with combined use of marble
powder, limestone filler, and fly ash. Construction and Building Materials, 37, pp.160-170.

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Girón, R.P., Ruiz, B., Fuente, E., Gil, R.R. and Suárez-Ruiz, I., 2013. Properties of fly ash from
forest biomass combustion. Fuel, 114, pp.71-77.
Kumar, A. and Kumar, S., 2013. Development of paving blocks from synergistic use of red mud
and fly ash using geopolymerization. Construction and building Materials, 38, pp.865-871.
Pandian, N.S., 2013. Fly ash characterization with reference to geotechnical applications. Journal
of the Indian Institute of Science, 84(6), p.189.
Ryu, G.S., Lee, Y.B., Koh, K.T. and Chung, Y.S., 2013. The mechanical properties of fly ash-
based geopolymer concrete with alkaline activators. Construction and Building Materials, 47,
pp.409-418.
Sarker, P.K., Haque, R. and Ramgolam, K.V., 2013. Fracture behaviour of heat cured fly ash
based geopolymer concrete. Materials & Design, 44, pp.580-586.
Singh, R.K. and Gupta, N.C., 2014. Value added utilization of fly ash-prospective and
sustainable solutions. International Journal of Applied Science and Engineering Research, 3(1),
pp.1-16.
Thomas, M., 2013. Supplementary cementing materials in concrete. CRC Press.
Ukwattage, N.L., Ranjith, P.G. and Bouazza, M., 2013. The use of coal combustion fly ash as a
soil amendment in agricultural lands (with comments on its potential to improve food security
and sequester carbon). Fuel, 109, pp.400-408.
Yao, Z.T., Ji, X.S., Sarker, P.K., Tang, J.H., Ge, L.Q., Xia, M.S. and Xi, Y.Q., 2015. A
comprehensive review on the applications of coal fly ash. Earth-Science Reviews, 141, pp.105-
121.

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Zhang, M., El-Korchi, T., Zhang, G., Liang, J. and Tao, M., 2014. Synthesis factors affecting
mechanical properties, microstructure, and chemical composition of red mud–fly ash based
geopolymers. Fuel, 134, pp.315-325.