Effects of chemical reagents on the properties of fly ash based geopolymer

Geopolymer with high calcium fly ash has a wide prospect in the field of construction, hence due to this fact, it has been significantly considered in the initiation of new era of green materials. Nevertheless, introducing high calcium fly ash in geopolymer has also created a few problems. Addition...

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Main Author:	Norbaizurah, Rahman
Format:	Thesis
Language:	English
Published:	2015
Subjects:	QD Chemistry
Online Access:	http://umpir.ump.edu.my/id/eprint/10980/1/Effects%20of%20chemical%20reagents%20on%20the%20properties%20of%20fly%20ash%20based%20geopolymer.pdf
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spelling	my-ump-ir.109802021-11-02T02:39:05Z Effects of chemical reagents on the properties of fly ash based geopolymer 2015-03 Norbaizurah, Rahman QD Chemistry Geopolymer with high calcium fly ash has a wide prospect in the field of construction, hence due to this fact, it has been significantly considered in the initiation of new era of green materials. Nevertheless, introducing high calcium fly ash in geopolymer has also created a few problems. Addition of high proportion of Ca in geopolymer has diverse effects on the reactivity of fly ash in geopolymer. Moreover, it also could hinder the polymerization process and alter the microstructure of geopolymer. It will significantly result in the high viscosity and contribute to the rapid setting time, low workability and low compressive strength performance. Therefore, alternative chemical reagents such as sodium nitrate, calcium nitrate, citric acid, sucrose and di-potassium hydrogen phosphate with dosage of 0.5 %, 1.5 % and 2.5 % were studied to overwhelm these issues in high calcium geopolymer. The effect of these admixtures on fresh geopolymer was evaluated by considering the setting time and flow table workability characteristic. Another set of parameters like degree of hydration, compressive strength, porosity, scanning electron microscopy and energy-dispersive X-ray spectroscopy tests were conducted to provide the fundamental and elemental composition information on the hardened geopolymer binder. The result shows that the increment of sodium nitrate with proportion of 0.5 % to 2.5 % by weight of fly ash considerably exhibits a prolonged initial setting time but decreased the flowability of geopolymer binder. Meanwhile, calcium nitrate and sucrose has increased the flowability of geopolymer binder while reduced the setting time. Inclusion of di-potassium hydrogen phosphate and citric acid has accelerated the setting time and reduced the flowability of geopolymer binder with the increment of the dosage. The compressive strength of geopolymer binder with the inclusion of alternative chemical reagents are all higher than control except for inclusion of calcium nitrate. Inclusion of 0.5 % alternative chemical reagents were observed to be effective as a retarder and significantly causes the extension of initial setting time. Each type of alkali cation and anion have its own effects on every stage of geopolymerization process. They play the main role in ascertaining the final structure by controlling the crystal growth and contributes to the structural development by forming alumino-silicate structures. Therefore it is concluded that the 0.5 % incorporation of alternative chemical reagents has the potential use as the chemical admixtures for geopolymer 2015-03 Thesis http://umpir.ump.edu.my/id/eprint/10980/ http://umpir.ump.edu.my/id/eprint/10980/1/Effects%20of%20chemical%20reagents%20on%20the%20properties%20of%20fly%20ash%20based%20geopolymer.pdf pdf en public masters Universiti Malaysia Pahang Faculty of Civil Engineering and Earth Resources
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Norbaizurah, Rahman Effects of chemical reagents on the properties of fly ash based geopolymer
description	Geopolymer with high calcium fly ash has a wide prospect in the field of construction, hence due to this fact, it has been significantly considered in the initiation of new era of green materials. Nevertheless, introducing high calcium fly ash in geopolymer has also created a few problems. Addition of high proportion of Ca in geopolymer has diverse effects on the reactivity of fly ash in geopolymer. Moreover, it also could hinder the polymerization process and alter the microstructure of geopolymer. It will significantly result in the high viscosity and contribute to the rapid setting time, low workability and low compressive strength performance. Therefore, alternative chemical reagents such as sodium nitrate, calcium nitrate, citric acid, sucrose and di-potassium hydrogen phosphate with dosage of 0.5 %, 1.5 % and 2.5 % were studied to overwhelm these issues in high calcium geopolymer. The effect of these admixtures on fresh geopolymer was evaluated by considering the setting time and flow table workability characteristic. Another set of parameters like degree of hydration, compressive strength, porosity, scanning electron microscopy and energy-dispersive X-ray spectroscopy tests were conducted to provide the fundamental and elemental composition information on the hardened geopolymer binder. The result shows that the increment of sodium nitrate with proportion of 0.5 % to 2.5 % by weight of fly ash considerably exhibits a prolonged initial setting time but decreased the flowability of geopolymer binder. Meanwhile, calcium nitrate and sucrose has increased the flowability of geopolymer binder while reduced the setting time. Inclusion of di-potassium hydrogen phosphate and citric acid has accelerated the setting time and reduced the flowability of geopolymer binder with the increment of the dosage. The compressive strength of geopolymer binder with the inclusion of alternative chemical reagents are all higher than control except for inclusion of calcium nitrate. Inclusion of 0.5 % alternative chemical reagents were observed to be effective as a retarder and significantly causes the extension of initial setting time. Each type of alkali cation and anion have its own effects on every stage of geopolymerization process. They play the main role in ascertaining the final structure by controlling the crystal growth and contributes to the structural development by forming alumino-silicate structures. Therefore it is concluded that the 0.5 % incorporation of alternative chemical reagents has the potential use as the chemical admixtures for geopolymer
format	Thesis
qualification_level	Master's degree
author	Norbaizurah, Rahman
author_facet	Norbaizurah, Rahman
author_sort	Norbaizurah, Rahman
title	Effects of chemical reagents on the properties of fly ash based geopolymer
title_short	Effects of chemical reagents on the properties of fly ash based geopolymer
title_full	Effects of chemical reagents on the properties of fly ash based geopolymer
title_fullStr	Effects of chemical reagents on the properties of fly ash based geopolymer
title_full_unstemmed	Effects of chemical reagents on the properties of fly ash based geopolymer
title_sort	effects of chemical reagents on the properties of fly ash based geopolymer
granting_institution	Universiti Malaysia Pahang
granting_department	Faculty of Civil Engineering and Earth Resources
publishDate	2015
url	http://umpir.ump.edu.my/id/eprint/10980/1/Effects%20of%20chemical%20reagents%20on%20the%20properties%20of%20fly%20ash%20based%20geopolymer.pdf
_version_	1783731935432933376

Effects of chemical reagents on the properties of fly ash based geopolymer

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