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1999
The portland cement used for construction of rigid pavements is an energy intensive material and hence efforts are being made to find substitute materials for partial replacement of cement in concrete, and conserve energy. On the other hand, utilisation of coal for generation of power is increasing rapidly. This has resulted in production of large quantities of fly ash from coal burning power plants. Fly ash from thermal power plants can be used as an admixture to concrete for saving cement as well as to provide solutions for its disposal problems. Use of fly ash in concrete would be an environmentally friendly way of utilising a waste material like fly ash. Currently fly ash finds application in road pavement structure,mainly for sub-base /base course and embankment. Fly ash admixed concrete can be a very good material for construction of pavement. It is generally designed as a partial replacement of cement or aggregate or both. This paper describes the different methods of using f...
International Journal of Current Engineering and Scientific Research, 2019
Mining industry produces a large quantity of waste every year resulting in severe damage to the environment. The wastes that are produced during mining should be efficiently disposed or effectively reused for any other productive purposes. Coal and lignite mining results in considerable dust pollutions very specifically the coal beneficiation process produces extensive amount of ashes. These ashes can be utilized in construction materials rather than dumping as landfill. When dumped as landfills, these ashes have the tendency to be carried away by the wind resulting in massive damage to the surrounding environment. This study is made to investigate whether this fly ash can be used as an ingredient in concrete preparation as a partial replacement for cement by studying the strength properties of fly ash mixed concrete. The strength properties of concrete when certain percentage of cement in the concrete is replaced with fly ash are studied. The replacement percentage of cement is maintained at 10%, 20%, 30%, 40% and 50% and the samples are tested in the laboratory after the curing period of 21 days. The workability, tensile strength, compressive strength and shear strength of the fly ash mixed concrete sample are determined. Similar tests are conducted on concrete with no fly ash content and both results are compared to find the optimum amount of fly ash that can be replaced without compromising the quality of the concrete. By utilizing fly ash as partial replacement to cement the percentage of CO2 emitted due to cement manufacturing can also be considerable reduced.
Fly ash concrete has economical and environmental advantages. It also makes concrete sustainable. In India presently less than 50% of fly ash produced is consumed. Infrastructural Development is at its peak all over the world and is a symbol of growth for any country. The most popular construction material, involves use of cement which is responsible for 7% of total world's carbon dioxide emissions. Carbon dioxide is the main threat in causing global warming of the environment. The attempts have been made to reduce CO 2 emissions in environment by all possible ways, but cement has not found a suitable replacement for it till date. Fly ash Concrete is an effort in reducing cement content of construction. The paper aims at discussing the use of fly ash concrete in construction as a solution to address two environmental problems-one, disposal of huge amounts of fly ash, by production of thermal power plants, causing environmental degradation through large areas of landfills and two...
2015
The use of recycled materials in road construction has been around for many years and with the environment getting severely affected by the daily use of natural resources used in construction, every bit of intervention that can provide a relief to the environment is greatly welcomed. This study looked at one of the ways the industry can play a big role in promoting recycling of by-products such as fly ash, on a larger scale, in the cement and concrete industry, by utilizing the fly ash to the optimum. Concrete mixtures of 35MPa with fly ash partially substituting the cement at four levels, 30%, 40%, 50% and 60%, were produced and numerous tests were performed to determine an optimum amount of fly ash that can be used and still obtain better or comparable concrete to ordinary concrete. Performing concrete tests such as compressive strength, durability, slump and setting was done at the Durban University of Technology and Contest laboratories over a period of one year. Also a cost com...
2018
The attempts have been made to reduce CO2emissions in environment by all possible ways, but cement has not found a suitable replacement for it till date. Fly ash concrete has economical and environmental advantages. It also makes concrete sustainable. In India presently less than 50% of fly ash produced is consumed. Infrastructural Development is at its peak all over the world and is a symbol of growth for any country. Fly ash Concrete is an effort in reducing cement content of construction. The paper aims at discussing the use of fly ash concrete in construction as a solution to address two environmental problems one, disposal of huge amounts of fly ash, by production of thermal power plants, causing environmental degradation through large areas of landfills and two, high percentage of carbon dioxide emissions in atmosphere from cement industry. The era of infrastructure increased in recent year, so the advancement of concrete technology exaggerated day by day in life. Use of concr...
Journal of Civil Engineering and Management, 2004
This work presents a study on the influence of thermal-electrical fly ash on the cement paste hydration processes, investigation into cement stone, mortar, ordinary and self-compacting concrete, when cement was replaced by fly ash (533 %). It was estimated that cement stone and cement paste prepared from fly ash and cement properties were better when polycarboxylic superplasticiser Visco Crete-3 was used. It was established that admixture of fly ash influences the processes of cement hydration: the amount of free Ca(OH) 2 in cement stone was decreased and amount of stable calcium hydro silicates was increased. It allows to state, that cement stone becomes more corrosion-resistant and more durable. When fly ash admixture is applied in ordinary concrete production, it is possibility to reduce cement expenditures up to 33 % and in self-compacting concrete production, segregation and separation of water decreases. Data of investigations on hardened concrete showed that fly ash increases compressive strength (up to 15 %), decreases shrinkage strains (up to 31,6 %), increases plastic deformations (up to 38 %), modulus of elasticity (up to 15 %) and modifies other concrete properties.
2016
The usage of fly ash products by the South African cement and construction industries has saved the country over 6 million tons of harmful greenhouse gas emissions. The recycling of it as cement extenders provides an immediate benefit for the environment while still improving the quality of concrete, and increasing the amount used in concrete can promote sustainable development. This study evaluated properties of 35MPa/9,5mm concrete with fly ash substituted at 30%, 40%, 50% and 60%. Increasing the fly ash content can result in more workable and less permeable concrete. The compressive strength and durability index results showed that the fly ash content can be increased beyond 50% and still achieve the required strength and produce durable concrete. Substituting high volumes of cement with fly ash in concrete can provide good quality concrete and a relief to the environment without compromising the quality and cost of concrete.
2014
The following paper is related with finding out the utilization of fly ash in improving concrete prope rties and its several environmental benefits. Fly ash is pozzolon ic material & it improves the properties of concret e like compressive strength & Durability. Here the method used for determining this is experimental. Here cub es casted with different amounts of fly ash proportions rangi ng from 10%-30% are used and their 7 and 28 days strength are found out. The strength of cubes was found out by t he use of compressive testing machine. Their degree of economy has also been found out. In the present study the r esults obtained are discussed and compared with the available literature.
Aim of the study is to analysis the properties of concrete with adding fly ash. So using this waste in road construction can dispose this waste and also beneficial in minimize pollution in environment due to this waste. It saves the cement requirement for the same strength thus saving of raw material. In present study aims preparing concrete by replacement of Ordinary Portland Cement (OPC) with fly ash. A comparison is made between fly ash and cement properties which are used as sub-grade, base in Highway construction.
Jurnal Teknik Sipil dan Perencanaan, 2018
The use of coal waste (Fly Ash) is currently being developed in building materials technology, as a highstrength concrete mix material. This study aims to determine the strength of concrete by adding fly ash as a substitute for cement in high-strength concrete mixtures. This research was conducted using an experimental method to obtain results and data that would confirm the variables studied. The total numbers of specimens used in this study were 36 pieces with different sizes of cube tests which were 15 cm x 15 cm x 15 cm. A total of 36 concrete samples were used to test the compressive strength of concrete with a percentage of Fly Ash in 0% (normal concrete), 20%, 25% and 30% with a concrete treatment age of 7 days, 21 days and 28 days. A total of 12 more samples were used to test water absorption in concrete at 28 days of maintenance. Each percentage of Fly Ash uses 3 concrete test samples. The increase in compressive strength occurs at 7, 21 and 28 days in concrete. However, the compressive strength of concrete produced by concrete using the percentage of Fly Ash is always lower than the value of normal concrete compressive strength. From testing the compressive strength of concrete at 28 days of treatment with
The tremendous improvement in the civilization and industrialization brought us many fruitful benefits through science and technology for the mankind but on the other hand it resulted in the alarming situation such as global warming. The high emission of CO 2 from cement industry, waste products from the thermal plants for the generation of electric power to meet the demand of growing population resulted in the production of tonnes of fly ash, bottom ash and boiler slag which causes environmental pollution. The cement and construction industries have utilized enough natural materials (fine and coarse aggregates) from the earth, as a result there is a scarcity of raw materials for cement and construction industries and price of these materials are increased. Global warming, tonnes of waste materials, scarcity of raw materials (fine and coarse aggregates) made researchers and scientists to think of reducing CO 2 emission from cement industries and effective utilization of waste materials from the thermal power plants by finding an alternate material for construction. Utilization of fly ash will result in the prevention of environment from the disposal problems of fly ash for the sustainable development for the future. This review paper explains the various utilization of fly ash and its properties in concrete.
In this paper, the obtained results of fly ash exploitability testing as a partial cement replacement into the concrete cover of pavement are presented. In accordance with the proposed recipe the specified amount of cement in concrete mixture was replaced by 5-15% ENO fly ash. Fresh concrete mixture, compressive strength and combined stresses strength after 7, 28 and 90 days of hardening composites as well as frost and chemical resistance were tested and compared with reference composite (the concrete of class C 30/37) which satisfies the Technical standards requirements. Results showed that alternative utilization of FA have significant contribution in environmental as well as in economic area.
In today's world the main emphasis is on green and sustainable development. Presently large amount of fly ash is generated in thermal power plants as a waste material with an improper impact on environment and humans. Fly ash a waste generated by thermal power plants is as such a big environmental concern. The experimental studies on mortar containing fly ash as a partial replacement of sand by weight as well as by volume were carried out to quantify its utilization. Both the types of pond and bottom fly ash in various ratios were used in preparing cement mortar and their strengths in compression and tension were tested. The use of fly ash in concrete formulations as a supplementary cementatious material was tested as an alternative to traditional concrete. The cement has been replaced by fly ash accordingly in the range of 0% (without fly ash), 10%, 20%, 30% & 40% by weight of cement for M-25 and M-40 mix. These tests were carried out to evaluate the mechanical properties for the test results for compressive strength up to 28 days and split strength for 56 days are taken.
Theoretical Foundations of Chemical Engineering, 2012
The world faces a number of environmental issues. Many of these problems are man made, the results of industrialization and building. There are many ways to help our world to become more environmen tally friendly and healthier. Cutting back of carbon dioxide emissions by using less energy consumptive mate rials in the building industry is one of them. Waste products used as a replacement of old raw materials lead to the less energy consumption and cost saving. The tests results of energy waste (fly ash) exploitability as a partial cement replacement into the concrete cover of pavement is described in this paper. Compressive and flexural strengths at hardened ages of 7, 28, 90 days, chemical resistance, freezing and thawing of fly ash con crete composites were measured and compared with the reference specimen (C 30/37), which met the requirements of STN 73 6123 Building of road element.
2016
This paper is written to access the use of fly ash, a waste product by thermal power plant, as an ingredient of concrete used for various engineering purposes such as production of pozzolana Portland cement, geopolymer concrete, lightweight concrete, precast concrete industry, manufacture of precast Poly Vinyl Chloride (PVC) pipes and paver blocks, Self compacting concrete (SCC) and mass concrete etc. The area is of much importance in Indian context as about 145 million tones of fly ash is being produced in India annually from electricity generation plants and this figure is increasing with the growth of demand for energy. The disposal of high volume of fly ash is posing a threat to the environment and requires immediate attention. In present scenario the cement industry alone is responsible for 7% of all the CO2 being produced in the world. Using fly ash as an ingredient in concrete, the problem of safe disposal of fly ash can be addressed considerably. Moreover the use of fly ash ...
Indonesian Journal of Engineering and Science
Indonesia signed the Paris Agreement on facing climate change. Carbon dioxide is the main issue contributing to the greenhouse effect. Most power plant in Indonesia uses non-renewable energy to generate electricity. Increasing demand for electricity makes increasing coal consumption for steam power plants and directly contributes to greenhouse gasses from coal combustion and produces fly ash as a waste product. Otherwise, fly ash from Steam Power Plant is classified as pozzolanic materials being a part of substitution ordinary portland cement (OPC) on making reinforcement concrete. Many Researchers studied reinforcement concrete from fly ash composition and others development using renewable energy resources such as biomass. This paper presents a literature review on focus studying the properties of various types of fly ash and their effect on the performance of concrete, including corrosion resistance.
IAEME PUBLICATION, 2020
The constant cement production results in a rise in carbon dioxide released into the air, which harms the ecosystem and causes greenhouse effects that cause climate change. The establishment of new sustainable material is thus becoming imperative as an alternative to normal concrete. To this end, several studies have been carried out with a partial or total replacement of cement by fly ash. Products with the inclusion of fly ash are considered a relatively new, innovative, and sustainable material with many advantages, including high strength, reduced use of natural resources, costeffectiveness. This study has carried an overview of the utilization of fly ashes in geopolymer, engineered cementitious composites (ECC), roller compacted concrete (RCC), previous concrete, and masonry bricks. The findings showed that the utilization of fly ash to manufacture concrete and masonry products which contribute to sustainable materials and environment-friendly building products.
UKH Journal of Science and Engineering, 2021
Cement is one of the most widely used building materials on the planet. Cement manufacturing has also increased carbon emissions to their greatest level in recent years. Alternative or low-emissions binders have become more popular as a partial cement substitute in recent years. Because of its huge yearly output as waste material and low cost, fly ash is now regarded as one of the most accessible choices. Fly ash-based construction materials have a lot of promise as cement substitutes because of their high performance and inexpensive cost. The purpose of this article is to look at how fly ash affects the workability, setting time, compressive strength, and tensile strength of concrete. The kinds and characteristics of fly ash were also investigated.
International Journal of Scientific Research, 2012
As concrete usually has been produced by using high quality fly ash and without fly ash (standard concrete). By using high quality fly ash constituents, increase drastically the initial cost of concrete. The objectives of this research work were to intend to study the possibility of producing low cost concrete. To verify the impact of carbon content on fly ash on the strength and durability of concrete. For this purpose it was decided to enhance the 'as received' fly ash by eliminating particles coarser than 75μm, thus reducing the carbon content by 50%. It was also observed that the carbon content did have little impact on the strength and durability of concrete. Applications of fly ash, which is technically, sound, environmentally safe for sustainable development. Use of fly ash in various engineering applications can solve the problem of disposal of fly ash and other purposes. The major constituents of most of the fly ashes are Silica (SiO2), alumina (Al2O3), ferric oxide (Fe2O3) and calcium oxide (CaO). The other minor constituent of the fly ash are MgO, Na2O, K2O, SO3, MnO, TiO2 and unburnt carbon. This paper is study on low quality fly ash as an opportunity for sustainable and economical concrete for a new millennium.
2009
This research paper seeks to optimize the benefits of using High Lime fly ash in concrete as a replacement for large proportions of cement. High Lime fly ash is a type of sub-bituminous fly ash that is self-cementing as well as pozzolanic in nature. High Lime fly ash would be categorized as a Class C fly ash by ASTM because of its high calcium content, however its sulfur content exceeds the limit set in ASTM C618 The physical and chemical properties of this type of fly ash, particularly its fineness and carbon content properties (coarser particles and low carbon content), provide potential benefits. These two properties are of great concern since they will affect the air content and water demand of the concrete; parameters that greatly affect the durability and strength of concrete. This paper describes early stages of a project to study the use of large volumes of High Lime fly ash in concrete. During the project High Lime fly ash obtained from a local power plant will be used in t...
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