Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders

Ambient–cured plain geopolymer binders typically exhibit unacceptably prolonged setting time values and weak development of mechanical properties. In this paper, a focussed literature review was done on setting time effects of physical – chemical factors comprising sodium hydroxide concentration, li...

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Main Authors: Kwandiwe Magugu, Stephen Ekolu, Abdolhossein Naghizadeh, Henrry Quainoo
Format: Article
Language:English
Published: Pouyan Press 2025-01-01
Series:Computational Engineering and Physical Modeling
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Online Access:https://www.jcepm.com/article_213487_06f9612aae7d6a10d76dcce86490c293.pdf
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author Kwandiwe Magugu
Stephen Ekolu
Abdolhossein Naghizadeh
Henrry Quainoo
author_facet Kwandiwe Magugu
Stephen Ekolu
Abdolhossein Naghizadeh
Henrry Quainoo
author_sort Kwandiwe Magugu
collection DOAJ
description Ambient–cured plain geopolymer binders typically exhibit unacceptably prolonged setting time values and weak development of mechanical properties. In this paper, a focussed literature review was done on setting time effects of physical – chemical factors comprising sodium hydroxide concentration, liquid – to – solids ratio, sodium silicate – to – sodium hydroxide ratio, and the influence of precursor composition. Subsequently, an experimental study was done wherein 0% to 30% ground granulated blast–furnace slag (GGBS) or ordinary Portland cement (OPC) were incorporated into fly ash – based geopolymer (FA - GPC) mixtures to compare effects of the two setting time modifiers. Paste and mortar mixtures were subjected to compressive strength, drying shrinkage, and pore – related physical properties tests.It was found that a strong correlation exists between setting time and lime content or Ca/Al ratio of the precursor. Indeed, the starting materials that had compositional values of 5% to 20% CaO and/or Ca/Al ratio of 0.5 to 1.5, were found to exhibit stable performance. Incorporation of 10% OPC gave initial /final setting time values of 65 /106 mins that met standard criteria specified in EN 197-1 (2011) and/or ASTM’s C150. It was also observed that incorporation of 10% OPC and 20% GGBS exhibited contrasting shrinkage effects, wherein the former decreased while the latter significantly increased drying shrinkage to exceed the 0.10% maximum limit stipulated in ASTM C596.
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spelling doaj-art-86c036dfe89b4b82adcb2c65486d9a682025-08-20T03:38:01ZengPouyan PressComputational Engineering and Physical Modeling2588-69592025-01-0181507010.22115/cepm.2025.490076.1347213487Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer BindersKwandiwe Magugu0Stephen Ekolu1Abdolhossein Naghizadeh2Henrry Quainoo3Department of Civil Engineering, Nelson Mandela University, Gqeberha, South AfricaDepartment of Civil Engineering, Nelson Mandela University, Gqeberha, South AfricaDepartment of Engineering Sciences, University of the Free State, South AfricaDepartment of Civil Engineering Science, University of Johannesburg, South AfricaAmbient–cured plain geopolymer binders typically exhibit unacceptably prolonged setting time values and weak development of mechanical properties. In this paper, a focussed literature review was done on setting time effects of physical – chemical factors comprising sodium hydroxide concentration, liquid – to – solids ratio, sodium silicate – to – sodium hydroxide ratio, and the influence of precursor composition. Subsequently, an experimental study was done wherein 0% to 30% ground granulated blast–furnace slag (GGBS) or ordinary Portland cement (OPC) were incorporated into fly ash – based geopolymer (FA - GPC) mixtures to compare effects of the two setting time modifiers. Paste and mortar mixtures were subjected to compressive strength, drying shrinkage, and pore – related physical properties tests.It was found that a strong correlation exists between setting time and lime content or Ca/Al ratio of the precursor. Indeed, the starting materials that had compositional values of 5% to 20% CaO and/or Ca/Al ratio of 0.5 to 1.5, were found to exhibit stable performance. Incorporation of 10% OPC gave initial /final setting time values of 65 /106 mins that met standard criteria specified in EN 197-1 (2011) and/or ASTM’s C150. It was also observed that incorporation of 10% OPC and 20% GGBS exhibited contrasting shrinkage effects, wherein the former decreased while the latter significantly increased drying shrinkage to exceed the 0.10% maximum limit stipulated in ASTM C596.https://www.jcepm.com/article_213487_06f9612aae7d6a10d76dcce86490c293.pdffly ash geopolymerblast – furnace slagordinary portland cementsetting timedrying shrinkage
spellingShingle Kwandiwe Magugu
Stephen Ekolu
Abdolhossein Naghizadeh
Henrry Quainoo
Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
Computational Engineering and Physical Modeling
fly ash geopolymer
blast – furnace slag
ordinary portland cement
setting time
drying shrinkage
title Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
title_full Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
title_fullStr Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
title_full_unstemmed Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
title_short Mixture - Related Factors Influencing Setting for Ambient Curing of Fly Ash – Based Geopolymer Binders
title_sort mixture related factors influencing setting for ambient curing of fly ash based geopolymer binders
topic fly ash geopolymer
blast – furnace slag
ordinary portland cement
setting time
drying shrinkage
url https://www.jcepm.com/article_213487_06f9612aae7d6a10d76dcce86490c293.pdf
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