The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers

Inorganic polymers or simply geopolymers were synthesized in this study by the alkaline activation of local low-calcium (Class F) fly ash. The alkaline activator liquid used for the activation process was a mixture of sodium silicate (waterglass) and sodium hydroxide (NaOH) solution. The main pur...

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Main Author:	Omar, Abdul Kareem
Format:	Thesis
Language:	English
Subjects:	Geopolymers Inorganic polymers Mineral polymers Fly ash Geopolymerization process Alkaline activator
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/1/p.%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/2/Full%20Text.pdf
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spelling	my-unimap-128432011-06-28T08:41:43Z The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers Omar, Abdul Kareem Inorganic polymers or simply geopolymers were synthesized in this study by the alkaline activation of local low-calcium (Class F) fly ash. The alkaline activator liquid used for the activation process was a mixture of sodium silicate (waterglass) and sodium hydroxide (NaOH) solution. The main purpose of the research was to study the effect of the alkaline activator content and the alkaline activator constituents (Waterglass and NaOH solution) mixing ratio, on the compressive strength and on the microstructure of the resulted lowcalcium (Class F) Fly ash-based geopolymer. The geopolymers were prepared at fixed operation parameters, which were including: the concentration of NaOH solution (15M), additional water (17% of the geopolymer weight), mixing time (15min), dilation time (24hr), curing temperature (70°C), curing time (24hr), and aging time of (24hr). The alkaline activator content was verified according to the Activator/Fly ash mass ratios utilized in the current research, which were (0.3, 0.35, and 0.4), and verified the mixing ratios of the alkaline activator constituents or waterglass/NaOH ratios were (0.6, 0.8, 1.00, and 1.2). The highest compressive strength was obtained at highest alkaline activator content (Activator/Fly ash =0.4). The compressive strength and the SEM data also showed that for each Activator/Fly ash ratio (0.3, 0.35, and 0.4), an optimum waterglass/NaOH ratio of (0.8, 1.00, and 1.00 respectively); give the highest compressive strength and a homogenous, less porosity microstructure with less unreacted fly ash spheres. XRD analysis showed that the formed geopolymers at the optimum waterglass/NaOH ratios were mainly amorphous with presence of crystalline phases existed in the original fly ash and some zeolitic phases were formed during the geopolymerization process. The optimum compressive strength geopolymer (8.61 MPa, Activator/Fly ash ratio = 0.4, and waterglass/NaOH =1.00), shows low thermal durability at 400°C, by the formation of macrocracks on the sample surface due to the water evaporation and further deterioration and sintering process takes place at higher temperatures of 600 & 800°C. Universiti Malaysia Perlis 2010 Thesis en http://dspace.unimap.edu.my/123456789/12843 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/3/license.txt bad5bd15c5a6dc14042871f862185683 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/1/p.%201-24.pdf 15ef24292bd219ce24ca6bbb6eab3f9e http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/2/Full%20Text.pdf 74c7a1efb8601f25e844bb019b702861 Geopolymers Inorganic polymers Mineral polymers Fly ash Geopolymerization process Alkaline activator School of Materials Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
topic	Geopolymers Inorganic polymers Mineral polymers Fly ash Geopolymerization process Alkaline activator
spellingShingle	Geopolymers Inorganic polymers Mineral polymers Fly ash Geopolymerization process Alkaline activator Omar, Abdul Kareem The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
description	Inorganic polymers or simply geopolymers were synthesized in this study by the alkaline activation of local low-calcium (Class F) fly ash. The alkaline activator liquid used for the activation process was a mixture of sodium silicate (waterglass) and sodium hydroxide (NaOH) solution. The main purpose of the research was to study the effect of the alkaline activator content and the alkaline activator constituents (Waterglass and NaOH solution) mixing ratio, on the compressive strength and on the microstructure of the resulted lowcalcium (Class F) Fly ash-based geopolymer. The geopolymers were prepared at fixed operation parameters, which were including: the concentration of NaOH solution (15M), additional water (17% of the geopolymer weight), mixing time (15min), dilation time (24hr), curing temperature (70°C), curing time (24hr), and aging time of (24hr). The alkaline activator content was verified according to the Activator/Fly ash mass ratios utilized in the current research, which were (0.3, 0.35, and 0.4), and verified the mixing ratios of the alkaline activator constituents or waterglass/NaOH ratios were (0.6, 0.8, 1.00, and 1.2). The highest compressive strength was obtained at highest alkaline activator content (Activator/Fly ash =0.4). The compressive strength and the SEM data also showed that for each Activator/Fly ash ratio (0.3, 0.35, and 0.4), an optimum waterglass/NaOH ratio of (0.8, 1.00, and 1.00 respectively); give the highest compressive strength and a homogenous, less porosity microstructure with less unreacted fly ash spheres. XRD analysis showed that the formed geopolymers at the optimum waterglass/NaOH ratios were mainly amorphous with presence of crystalline phases existed in the original fly ash and some zeolitic phases were formed during the geopolymerization process. The optimum compressive strength geopolymer (8.61 MPa, Activator/Fly ash ratio = 0.4, and waterglass/NaOH =1.00), shows low thermal durability at 400°C, by the formation of macrocracks on the sample surface due to the water evaporation and further deterioration and sintering process takes place at higher temperatures of 600 & 800°C.
format	Thesis
author	Omar, Abdul Kareem
author_facet	Omar, Abdul Kareem
author_sort	Omar, Abdul Kareem
title	The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
title_short	The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
title_full	The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
title_fullStr	The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
title_full_unstemmed	The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
title_sort	role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers
granting_institution	Universiti Malaysia Perlis
granting_department	School of Materials Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/1/p.%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/12843/2/Full%20Text.pdf
_version_	1747836761436848128

The role of alkaline activator in geopolymerization of low-calcium fly ash based geopolymers

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