Effect of mixing condotions on the properties and characteristic of kaolin geopolymers

Geopolymerization process utilizing kaolin as aluminosilicate source was performed. The goal of this study was to investigate the effect of NaOH concentration, S/L ratio, Na2SiO3/NaOH ratio, curing temperature and time as well as mechanical treatment of kaolin on kaolin geopolymers. The results s...

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Main Author:	Heah, Cheng Yong
Format:	Thesis
Language:	English
Subjects:	Kaolin geopolymers Kaolin Geopolymerization Geopolymers
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/1/P.1-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/2/Full%20Text.pdf
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spelling	my-unimap-428802016-09-19T07:35:03Z Effect of mixing condotions on the properties and characteristic of kaolin geopolymers Heah, Cheng Yong Geopolymerization process utilizing kaolin as aluminosilicate source was performed. The goal of this study was to investigate the effect of NaOH concentration, S/L ratio, Na2SiO3/NaOH ratio, curing temperature and time as well as mechanical treatment of kaolin on kaolin geopolymers. The results showed that 8M of NaOH concentration, S/L ratio of 1.00, Na2SiO3/NaOH ratio of 0.32 and curing conditions at 60°C for 72 hours were the optimum mixing conditions for kaolin geopolymers synthesis. In order to increase the reactivity of kaolin towards geopolymerization reaction, mechanical treatment of kaolin was conducted through milling process. The optimum milling time of kaolin was 5 hours. Mechanical treatment of kaolin has successfully decreased the particle size and increased the surface area of kaolin particles, producing mechanicaltreated kaolin geopolymers with better compressive strength (9.58 MPa) compared to kaolin geopolymer synthesized with untreated kaolin (5.94 MPa). Bulk density measurement showed that kaolin geopolymers were lightweight (< 1870 kg/m3). During the geopolymers synthesis, workability must be taking into consideration since it affected significantly the strength development of kaolin geopolymers. Microstructural analysis (SEM) revealed that kaolin geopolymers only undergo low dissolution as shown by the presence of large amounts of unreacted kaolin particles in the microstructure of kaolin geopolymers. However, the formation of homogeneous geopolymer gel was observed at longer day of testing. Besides, elemental composition analysis (EDX) results supports the continuous development of geopolymer structure as indicated by the increased Na/Al and Si/Al ratios by the day of testing. Zeolites peaks appeared in kaolin geopolymers after the geopolymerization reaction as determined by phase analysis (XRD). The amorphous geopolymer and crystalline zeolite phases contributed to the strength of geopolymers. Even so, these crystalline zeolites peaks gradually decreased in intensity at longer day of testing and were found degraded the compressive strength of geopolymers. Functional group identification (FTIR) shows the formation of more geopolymer bonding in kaolin geopolymers at longer testing day. On the other hand, based on compressive strength results, the optimum oxide molar ratios of SiO2/Al2O3, Na2O/SiO2, H2O/Na2O and Na2O/Al2O3 for kaolin geopolymers synthesis were concluded at 3.28, 0.28, 14.61 and 0.92, respectively. In general, kaolin has low reactivity and it required more time for dissolution in alkaline activator solution and hence the formation of geopolymer structure. The slow rate of geopolymerization reaction led to a slow strength development of geopolymers. As a conclusion, this study provides a better understanding of the properties (compressive strength, workability and bulk density) and characteristic (microstructure, phases and functional groups) of kaolin geopolymers. Thus, for future research, it is suggested to increase the reactivity of kaolin towards geopolymerization reaction in order to improve the mechanical strength. Universiti Malaysia Perlis (UniMAP) 2014 Thesis en http://dspace.unimap.edu.my:80/xmlui/handle/123456789/42880 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/3/license.txt 8a4605be74aa9ea9d79846c1fba20a33 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/1/P.1-24.pdf 12c0485d9bce29cf59bca49cf8637805 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/2/Full%20Text.pdf 242d024ffe07bf1faffad850aeff41a2 Kaolin geopolymers Kaolin Geopolymerization Geopolymers School of Materials Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
topic	Kaolin geopolymers Kaolin Geopolymerization Geopolymers
spellingShingle	Kaolin geopolymers Kaolin Geopolymerization Geopolymers Heah, Cheng Yong Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
description	Geopolymerization process utilizing kaolin as aluminosilicate source was performed. The goal of this study was to investigate the effect of NaOH concentration, S/L ratio, Na2SiO3/NaOH ratio, curing temperature and time as well as mechanical treatment of kaolin on kaolin geopolymers. The results showed that 8M of NaOH concentration, S/L ratio of 1.00, Na2SiO3/NaOH ratio of 0.32 and curing conditions at 60°C for 72 hours were the optimum mixing conditions for kaolin geopolymers synthesis. In order to increase the reactivity of kaolin towards geopolymerization reaction, mechanical treatment of kaolin was conducted through milling process. The optimum milling time of kaolin was 5 hours. Mechanical treatment of kaolin has successfully decreased the particle size and increased the surface area of kaolin particles, producing mechanicaltreated kaolin geopolymers with better compressive strength (9.58 MPa) compared to kaolin geopolymer synthesized with untreated kaolin (5.94 MPa). Bulk density measurement showed that kaolin geopolymers were lightweight (< 1870 kg/m3). During the geopolymers synthesis, workability must be taking into consideration since it affected significantly the strength development of kaolin geopolymers. Microstructural analysis (SEM) revealed that kaolin geopolymers only undergo low dissolution as shown by the presence of large amounts of unreacted kaolin particles in the microstructure of kaolin geopolymers. However, the formation of homogeneous geopolymer gel was observed at longer day of testing. Besides, elemental composition analysis (EDX) results supports the continuous development of geopolymer structure as indicated by the increased Na/Al and Si/Al ratios by the day of testing. Zeolites peaks appeared in kaolin geopolymers after the geopolymerization reaction as determined by phase analysis (XRD). The amorphous geopolymer and crystalline zeolite phases contributed to the strength of geopolymers. Even so, these crystalline zeolites peaks gradually decreased in intensity at longer day of testing and were found degraded the compressive strength of geopolymers. Functional group identification (FTIR) shows the formation of more geopolymer bonding in kaolin geopolymers at longer testing day. On the other hand, based on compressive strength results, the optimum oxide molar ratios of SiO2/Al2O3, Na2O/SiO2, H2O/Na2O and Na2O/Al2O3 for kaolin geopolymers synthesis were concluded at 3.28, 0.28, 14.61 and 0.92, respectively. In general, kaolin has low reactivity and it required more time for dissolution in alkaline activator solution and hence the formation of geopolymer structure. The slow rate of geopolymerization reaction led to a slow strength development of geopolymers. As a conclusion, this study provides a better understanding of the properties (compressive strength, workability and bulk density) and characteristic (microstructure, phases and functional groups) of kaolin geopolymers. Thus, for future research, it is suggested to increase the reactivity of kaolin towards geopolymerization reaction in order to improve the mechanical strength.
format	Thesis
author	Heah, Cheng Yong
author_facet	Heah, Cheng Yong
author_sort	Heah, Cheng Yong
title	Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
title_short	Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
title_full	Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
title_fullStr	Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
title_full_unstemmed	Effect of mixing condotions on the properties and characteristic of kaolin geopolymers
title_sort	effect of mixing condotions on the properties and characteristic of kaolin geopolymers
granting_institution	Universiti Malaysia Perlis (UniMAP)
granting_department	School of Materials Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/1/P.1-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42880/2/Full%20Text.pdf
_version_	1747836815743647744

Effect of mixing condotions on the properties and characteristic of kaolin geopolymers

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