New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators

This study investigates the activation of New Zealand pumicite (pumice powder) using sodium aluminate (NaAlO₂) solution, both alone and in combination with 10 M KOH solution, at various weight ratios of 1, 3, and 5, to produce alkali-activated cement. Compressive strength tests and microstructural a...

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Main Authors: Roohollah Kalatehjari, Elmira Khaksar Najafi, Afshin Asadi, Martin Brook
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509524011598
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author Roohollah Kalatehjari
Elmira Khaksar Najafi
Afshin Asadi
Martin Brook
author_facet Roohollah Kalatehjari
Elmira Khaksar Najafi
Afshin Asadi
Martin Brook
author_sort Roohollah Kalatehjari
collection DOAJ
description This study investigates the activation of New Zealand pumicite (pumice powder) using sodium aluminate (NaAlO₂) solution, both alone and in combination with 10 M KOH solution, at various weight ratios of 1, 3, and 5, to produce alkali-activated cement. Compressive strength tests and microstructural analyses were conducted to assess the effects of activator/precursor ratios, activator type, aging time, and curing temperature (65°C for 72 hours or room temperature). The internal porosity of the pumicite played a key role in aluminosilicate phase dissolution and mobility, resulting in similar compressive strengths across different ratios. NaAlO₂ alone achieved compressive strengths of 60 MPa and 67 MPa after 4 and 65 days, respectively, while the binary solutions showed reduced strength with increased aging. Room temperature curing required almost three times the aging period to match the 28-day compressive strengths achieved after curing at 65°C for 72 hours. Microstructural analyses revealed that NaAlO₂ solution adjusted the Si/Al ratio, forming high-Al and high-Si gels as well as zeolite-A, underscoring its benefits. This study demonstrates the potential of using locally sourced New Zealand pumicite as a precursor in alkali-activated cement, particularly in regions lacking traditional industrial by-products.
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publishDate 2024-12-01
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series Case Studies in Construction Materials
spelling doaj-art-5c17e652f2c74375b4e0f322b763e0dd2024-11-22T07:37:13ZengElsevierCase Studies in Construction Materials2214-50952024-12-0121e04008New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activatorsRoohollah Kalatehjari0Elmira Khaksar Najafi1Afshin Asadi2Martin Brook3Built Environment Engineering Department, School of Future Environments, Auckland University of Technology, Auckland 1010, New Zealand; Correspondence to: Auckland University of Technology, WZ Building, 6 St Paul Street, Auckland 1010, New Zealand.James Watt School of Engineering, University of Glasgow, United KingdomWilton Joubert Consulting Engineers, Auckland, New Zealand; EnvoGeotechnique Ltd., Auckland, New ZealandSchool of Environment, University of Auckland, Auckland 1010, New ZealandThis study investigates the activation of New Zealand pumicite (pumice powder) using sodium aluminate (NaAlO₂) solution, both alone and in combination with 10 M KOH solution, at various weight ratios of 1, 3, and 5, to produce alkali-activated cement. Compressive strength tests and microstructural analyses were conducted to assess the effects of activator/precursor ratios, activator type, aging time, and curing temperature (65°C for 72 hours or room temperature). The internal porosity of the pumicite played a key role in aluminosilicate phase dissolution and mobility, resulting in similar compressive strengths across different ratios. NaAlO₂ alone achieved compressive strengths of 60 MPa and 67 MPa after 4 and 65 days, respectively, while the binary solutions showed reduced strength with increased aging. Room temperature curing required almost three times the aging period to match the 28-day compressive strengths achieved after curing at 65°C for 72 hours. Microstructural analyses revealed that NaAlO₂ solution adjusted the Si/Al ratio, forming high-Al and high-Si gels as well as zeolite-A, underscoring its benefits. This study demonstrates the potential of using locally sourced New Zealand pumicite as a precursor in alkali-activated cement, particularly in regions lacking traditional industrial by-products.http://www.sciencedirect.com/science/article/pii/S2214509524011598New Zealand PumicitePumiceAlkali-Activated CementSodium AluminateMicrostructural Characterisation
spellingShingle Roohollah Kalatehjari
Elmira Khaksar Najafi
Afshin Asadi
Martin Brook
New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
Case Studies in Construction Materials
New Zealand Pumicite
Pumice
Alkali-Activated Cement
Sodium Aluminate
Microstructural Characterisation
title New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
title_full New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
title_fullStr New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
title_full_unstemmed New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
title_short New Zealand pumicite as a precursor in producing alkaline cement with aluminate-based activators
title_sort new zealand pumicite as a precursor in producing alkaline cement with aluminate based activators
topic New Zealand Pumicite
Pumice
Alkali-Activated Cement
Sodium Aluminate
Microstructural Characterisation
url http://www.sciencedirect.com/science/article/pii/S2214509524011598
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AT elmirakhaksarnajafi newzealandpumiciteasaprecursorinproducingalkalinecementwithaluminatebasedactivators
AT afshinasadi newzealandpumiciteasaprecursorinproducingalkalinecementwithaluminatebasedactivators
AT martinbrook newzealandpumiciteasaprecursorinproducingalkalinecementwithaluminatebasedactivators