Mix Design of Fly Ash Based Geopolymer Concrete
TL;DR: In this paper, an experimental investigation has been carried out for the gradation of geopolymer concrete and a mix design procedure is proposed on the basis of quantity and fineness of fly ash, quantity of water, grading of fine aggregate, fine to total aggregate ratio.
Abstract: Geopolymer is a new development in the world of concrete in which cement is totally replaced by pozzolanic materials like fly ash and activated by highly alkaline solutions to act as a binder in the concrete mix. For the selection of suitable ingredients of geopolymer concrete to achieve desire strength at required workability, an experimental investigation has been carried out for the gradation of geopolymer concrete and a mix design procedure is proposed on the basis of quantity and fineness of fly ash, quantity of water, grading of fine aggregate, fine to total aggregate ratio. Sodium silicate solution with Na2O = 16.37 %, SiO2 = 34.35 % and H2O = 49.28 % and sodium hydroxide solution having 13 M concentration were maintained constant throughout the experiment. Water-to-geopolymer binder ratio of 0.35, alkaline solution-to-fly ash ratio of 0.35 and sodium silicate-to-sodium hydroxide ratio of 1.0 by mass were fixed on the basis of workability and cube compressive strength. Workability of geopolymer concrete was measured by flow table apparatus and cubes of 150 mm side were cast and tested for compressive strength after specified period of oven heating. The temperature of oven heating was maintained at 60 °C for 24 h duration and tested 7 days after heating. It is observed that the results of workability and compressive strength are well match with the required degree of workability and compressive strength. So, proposed method is used to design normal and standard geopolymer concrete.
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TL;DR: In this paper, the alkaline solution of sodium silicate and sodium hydroxide is mixed with processed fly ash to become geopolymer concrete and this concrete is cured at different condition and different temperature so as to increase the strength of concrete.
Abstract: Around 120 million tone of fly ash get accumulated every year at the thermal power stations in India. Similarly aggregate crusher units produce enormous quantities of stone dust, a waste product, produced during crushing of rubble. Due to scarcity of land disposal becomes a serious problem. Because of the growing concern with environmental issues and increasing interest in conservation of energy and resources, every country has to face the challenging problem that how to use or dispose this by-product within the framework of its economic structure. Due to this the fly ash is used as ingredients in concrete which enhance the properties of concrete and utilization of fly ash is helpful for consumption. In this study the alkaline solution of sodium silicate and sodium hydroxide is mixed with processed fly ash to become geopolymer concrete. This concrete is cured at different condition and different temperature so as to increase the strength of concrete. Keyword: Geopolymer Concrete, Processed Fly ash.
7 citations
TL;DR: In this article, the experimental investigations of durability properties as well as microstructural properties of geopolymer concrete with ferrochrome slag used as coarse aggregate were carried out.
Abstract: The present paper deals with the experimental investigations of durability properties as well as microstructural properties of geopolymer concrete with ferrochrome slag used as coarse aggregate. Geopolymeric binder was found out by activating fly ash with alkaline activators (NaOH and Na2SiO3). Geopolymer concrete (GPC) was produced by mixing fly ash, river sand, and natural coarse aggregate combined with ferrochrome slag. Test samples were immersed in 3% magnesium sulphate and 5% sodium chloride solutions for different periods. From this, durability properties were investigated. The change in compressive strength and weight was evaluated experimentally at 28, 56, and 90 days. The rate of water absorption was also found at 28, 56, and 90 days. Microstructural properties such as scanning electron microscope, X-ray diffraction, and Fourier transformed infrared spectroscopy of these samples were studied after 56-day immersion period in 3% MgSO4 and 5% NaCl solutions. These were compared with conventional GPC. Sorptivity of the GPC samples was very less about 0.05–0.1 which indicates the better resistance against the sorption. It was concluded that GPC based on ferrochrome slag exhibited strength loss within 4% and 3% at sulphate and chloride attack than control GPC.
6 citations
TL;DR: In this paper, an Artificial Neural Network (ANN) model has been applied to predict the effect of molar ratios on the 28-day compressive strength of fly ash-slag geopolymer mortar.
Abstract: Geopolymers are inorganic polymers produced by the alkali activation of alumina-silicate minerals. Geopolymer is an alternative cementitious binder to traditional Ordinary Portland Cement (OPC) leading to economical and sustainable construction technique by the utilisation of alumina-silicate waste materials. The strength development in fly ash-slag geopolymer mortar is dependent on the chemical composition of the raw materials. An effective way to study the effect of chemical components in geopolymer is through the evaluation of molar ratios. In this study, an Artificial Neural Network (ANN) model has been applied to predict the effect of molar ratios on the 28-day compressive strength of fly ash-slag geopolymer mortar. For this purpose, geopolymer mortar samples were prepared with different fly ash-slag composition, activator concentration, and alkaline solution ratios. The molar ratios of the geopolymer mortar samples were evaluated and given as input to ANN, and the compressive strength was obtained as the output. The accuracy of the assessed model was investigated by statistical parameters; the mean, median, and mode values of the ratio between actual and predicted strength are equal to 0.991, 0.973, and 0.991, respectively, with a 14% coefficient of variation and a correlation coefficient of 89%. Based on the mentioned findings, the proposed novel model seems reliable enough and could be used for the prediction of compressive strength of fly ash-slag geopolymer. In addition, the influence of molar compositions on the compressive strength was further investigated through parametric studies utilizing the proposed model. The percentages of Na2O and SiO2 of the source materials were observed as the dominant chemical compounds in the mix affecting the compressive strength. The influence of CaO was significant when combined with a high amount of SiO2 in alkaline solution.
6 citations
Cites background from "Mix Design of Fly Ash Based Geopoly..."
...Both FA and GGBFS are pozzolanic materials which are generally blended with OPC to produce Portland pozzolanic cement and are also used as workability-improving admixtures [7]....
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TL;DR: In this article, the alternating cementing material like fly ash, silica fume Ground granulated blast-furnace slag (GGBS) were used to decrease the need of cement and CO2 emission.
5 citations
01 Jan 2020
TL;DR: In this paper, the strength characteristics of GPC by using sodium silicate and sodium hydroxide combination used as alkali activator were investigated and the results obtained from GPC under ambient curing with combination of fly ash and GGBS gains the required strength and also elminates the oven curing.
Abstract: Portland cement (PC) is the most energy-intensive-based material, and also requires a huge amount of natural resources. At present, cement industries contribute 7% of the total CO2 emission into the atmosphere which results in increase in global warming effect. To control this negative effect, an alternative material is being developed. For this, geopolymer concrete (GPC) is such a material to replace the cement in construction industry. The present study focuses on the strength characteristics of GPC by using sodium silicate and sodium hydroxide combination used as alkali activator. The varied parameters are alkaline-to-binder ratio, binder content, fly ash and GGBS proportions and curing condition. To perform the experiments, a total of 60 specimens of size 100 mm × 100 mm × 100 mm were cast by adopting binder as 300 kg/m3. The results obtained from GPC under ambient curing with combination of fly ash and GGBS gains the required strength and also elminates the oven curing.
5 citations
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TL;DR: In the last few years, technological progress has been made in the development of new materials such as "geopolymers" and new techniques, such as ''sol-gel'' as mentioned in this paper, opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry.
Abstract: Spectacular technological progress has been made in the last few years through thedevelopment of new materials such as «geopolymers», and new techniques, such as «sol-gel». New state-of-the-art materials designed with the help of geopolymerization reactions are opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry. High temperature techniques arc no longer necessary to obtain materials which are ceramic-like in their structures and properties
3,178 citations
TL;DR: In this article, a statistical study of the effect on the polymerization process of the molar ratio of the component oxides and the water content of the mixture showed the latter to be a critical parameter.
933 citations
TL;DR: In this article, fly ash-based geopolymer concrete was developed to reduce greenhouse gas emissions, and the test results showed the effects of various parameters on the properties of the concrete.
Abstract: To reduce greenhouse gas emissions, efforts are needed to develop environmentally friendly construction materials. This paper presents the development of fly ash-based geopolymer concrete. In geopolymer concrete, a by-product material rich in silicon and aluminum, such as low-calcium (ASTM C 618 Class F) fly ash, is chemically activated by a high-alkaline solution to form a paste that binds the loose coarse and fine aggregates, and other unreacted materials in the mixture. The test results presented in this paper show the effects of various parameters on the properties of geopolymer concrete. The application of geopolymer concrete and future research needs are also identified.
797 citations
01 Jan 1994
229 citations
Journal Article•
TL;DR: In this article, the authors discuss the increase use of large volumes of fly ash and other supplementary cementing materials in the construction industry and its role in reducing these emissions, since the manufacture of portland cement contributes significantly to carbon dioxide emissions.
Abstract: Environmental issues will play a leading role in the sustainable development of the cement and concrete industry in the 21st century. The World Earth Summits in Rio de Janeiro, Brazil in 1992, and Kyoto, Japan in 1997, have made it abundantly clear that unchecked increased emission of greenhouse gases to the atmosphere is no longer environmentally and socially acceptable for overall sustainable development. The primary greenhouse gas emissions discussed in the sessions of the above conferences are carbon dioxide emissions. Other greenhouse gases such as nitrous oxide and methane, are of serious concern, but the amount involved is relatively small compared with that of carbon dioxide. Consequently, developed countries are considering regulations and mandatory quotas on the emission of these gases, and the main thrust is to stabilize these emissions to the 1990 level by the year 2010. Since the manufacture of portland cement contributes significantly to carbon dioxide emissions, this article discusses the increase use of large volumes of fly ash and other supplementary cementing materials in the construction industry and its role in reducing these emissions.
226 citations