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Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment

In cement industry, the emissions of greenhouse gases specifically CO2 from the clinker production led to the need of alternative binders. Geopolymer binder whose precursors are sourced from industrial by-products such as fly ash that are rich is silica and alumina has been studied extensively in...

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Main Authors: Sharon, Robert, Idawati, Ismail, Raudhah, Ahmadi, Nur Amalina Shairah, Abdul Samat
Format: Article
Language:English
Published: Trans Tech Publications Ltd, Switzerland 2021
Subjects:
TA Engineering (General). Civil engineering (General)
Online Access:http://ir.unimas.my/id/eprint/36399/1/chloride1.pdf
http://ir.unimas.my/id/eprint/36399/
https://www.scientific.net/DDF.411
http://10.4028/www.scientific.net/DDF.411.143
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spelling my.unimas.ir.363992021-10-13T06:18:00Z http://ir.unimas.my/id/eprint/36399/ Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment Sharon, Robert Idawati, Ismail Raudhah, Ahmadi Nur Amalina Shairah, Abdul Samat TA Engineering (General). Civil engineering (General) In cement industry, the emissions of greenhouse gases specifically CO2 from the clinker production led to the need of alternative binders. Geopolymer binder whose precursors are sourced from industrial by-products such as fly ash that are rich is silica and alumina has been studied extensively in the past decades. Chloride attack is one of the threats to concrete structures. Analysis at microstructural level needs to be studied carefully before this binder can be used with confidence. This study attempts to compare the properties of fly ash geopolymer binder when exposed in water and chloride solution. Fly ash geopolymer pastes were prepared using 12M sodium hydroxide (NaOH) as activator. The pastes were tested under two separate curing conditions, i.e in ambient and in distilled water. Compressive strength test along with microstructure properties of samples cured at 7, 14 and 28 days were conducted via Universal testing machine, Fourier Transform Infra-Red (FTIR) spectroscopy and Scanning Electron Microscope with Energy-dispersive X-ray (SEM-EDX). After 28 days of curing, these samples were immersed in 10% sodium chloride (NaCl) solution for another 56 days. Samples cured in ambient condition showed better mechanical performance than those in distilled water. Their differences in compressive strength were also seen consistent with the FTIR results. Samples exposed to NaCl and distilled water showed similar mechanical performance and microstructural properties. Based on SEM-EDX analysis, samples cured in ambient were rich in silica and alumina while the intensity of these compounds were observed to reduce when exposed to distilled water. Samples cured in ambient showed stronger intensity of Si/Al gel as compared to samples exposed to chloride environment and distilled water and these were consistent with the compressive strength results obtained. When immersed in water, concentration gradient changes in the liquid phases, leading to ions diffusion and causing decrement in strength and durability of the solids in fly ash geopolymer. Trans Tech Publications Ltd, Switzerland 2021-09-08 Article PeerReviewed text en http://ir.unimas.my/id/eprint/36399/1/chloride1.pdf Sharon, Robert and Idawati, Ismail and Raudhah, Ahmadi and Nur Amalina Shairah, Abdul Samat (2021) Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment. Defect and Diffusion Forum, 411 (2021). pp. 143-155. ISSN 1662-9507 https://www.scientific.net/DDF.411 http://10.4028/www.scientific.net/DDF.411.143
institution Universiti Malaysia Sarawak
building Centre for Academic Information Services (CAIS)
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Sarawak
content_source UNIMAS Institutional Repository
url_provider http://ir.unimas.my/
language English
topic TA Engineering (General). Civil engineering (General)
spellingShingle TA Engineering (General). Civil engineering (General)
Sharon, Robert
Idawati, Ismail
Raudhah, Ahmadi
Nur Amalina Shairah, Abdul Samat
Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
description In cement industry, the emissions of greenhouse gases specifically CO2 from the clinker production led to the need of alternative binders. Geopolymer binder whose precursors are sourced from industrial by-products such as fly ash that are rich is silica and alumina has been studied extensively in the past decades. Chloride attack is one of the threats to concrete structures. Analysis at microstructural level needs to be studied carefully before this binder can be used with confidence. This study attempts to compare the properties of fly ash geopolymer binder when exposed in water and chloride solution. Fly ash geopolymer pastes were prepared using 12M sodium hydroxide (NaOH) as activator. The pastes were tested under two separate curing conditions, i.e in ambient and in distilled water. Compressive strength test along with microstructure properties of samples cured at 7, 14 and 28 days were conducted via Universal testing machine, Fourier Transform Infra-Red (FTIR) spectroscopy and Scanning Electron Microscope with Energy-dispersive X-ray (SEM-EDX). After 28 days of curing, these samples were immersed in 10% sodium chloride (NaCl) solution for another 56 days. Samples cured in ambient condition showed better mechanical performance than those in distilled water. Their differences in compressive strength were also seen consistent with the FTIR results. Samples exposed to NaCl and distilled water showed similar mechanical performance and microstructural properties. Based on SEM-EDX analysis, samples cured in ambient were rich in silica and alumina while the intensity of these compounds were observed to reduce when exposed to distilled water. Samples cured in ambient showed stronger intensity of Si/Al gel as compared to samples exposed to chloride environment and distilled water and these were consistent with the compressive strength results obtained. When immersed in water, concentration gradient changes in the liquid phases, leading to ions diffusion and causing decrement in strength and durability of the solids in fly ash geopolymer.
format Article
author Sharon, Robert
Idawati, Ismail
Raudhah, Ahmadi
Nur Amalina Shairah, Abdul Samat
author_facet Sharon, Robert
Idawati, Ismail
Raudhah, Ahmadi
Nur Amalina Shairah, Abdul Samat
author_sort Sharon, Robert
title Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
title_short Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
title_full Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
title_fullStr Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
title_full_unstemmed Comparison of Mechanical and Microstructural Properties of Fly Ash Geopolymer in Water and Chloride Environment
title_sort comparison of mechanical and microstructural properties of fly ash geopolymer in water and chloride environment
publisher Trans Tech Publications Ltd, Switzerland
publishDate 2021
url http://ir.unimas.my/id/eprint/36399/1/chloride1.pdf
http://ir.unimas.my/id/eprint/36399/
https://www.scientific.net/DDF.411
http://10.4028/www.scientific.net/DDF.411.143
_version_ 1715194124644122624
score 13.211869

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