Nano/microcharacterization and image analysis on bonding behaviour of ITZs in recycled concrete enhanced with waste glass powder

Zhao, H; Li, W; Gan, Y; Wang, K; Luo, Z

Nano/microcharacterization and image analysis on bonding behaviour of ITZs in recycled concrete enhanced with waste glass powder

Zhao, H Li, W

Gan, Y Wang, K Luo, Z

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Publisher:: Elsevier
Publication Type:: Journal Article
Citation:: Construction and Building Materials, 2023, 392, pp. 131904
Issue Date:: 2023-08-15

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Field	Value	Language
dc.contributor.author	Zhao, H
dc.contributor.author	Li, W https://orcid.org/0000-0002-4651-1215
dc.contributor.author	Gan, Y
dc.contributor.author	Wang, K
dc.contributor.author	Luo, Z
dc.date.accessioned	2024-05-07T03:59:42Z
dc.date.available	2024-05-07T03:59:42Z
dc.date.issued	2023-08-15
dc.identifier.citation	Construction and Building Materials, 2023, 392, pp. 131904
dc.identifier.issn	0950-0618
dc.identifier.uri	http://hdl.handle.net/10453/178719
dc.description.abstract	Waste glass powder (WGP) has been shown to help improve concrete properties. However, the underlying mechanism needs to be explored at the micro level, specifically on the interfacial transition zones (ITZs). This study aims to investigate the microtopography and bonding behaviours of ITZs using modelled recycled aggregate concrete (MRAC). To highlight the differences, two sets of MEAC were prepared, consisting of old and new mortars with water-cement ratios of 0.45 and 0.40, respectively. WGP was incorporaed in the new mortar, replacing 20 wt% of cement to enhance the performance of the new ITZ. Two groups of MRAC with three types of ITZs were successfully fabricated and studied. The property differences between the old ITZ, new ITZ without WGP, and new ITZ with WGP were comprehensively evaluated and compared based on phase distribution, chemical composition, and micromechanical properties. The results show that the new ITZ without WGP exhibited the highest porosity (avg. 7.29%) but a higher calcium silicate hydrate (C-S-H) elastic modulus (avg. 11.89 GPa) compared to the old ITZ (avg. 4.33% and 10.37 GPa, respectively). WGP effectively reduced the volume fraction of pores and cracks to 4.30% by reacting with calcium hydroxide (CH) within the new ITZ and the adjacent old mortar, resulting in generation of a significant amount of C-S-H gel with a Si/Ca ratio of approximately 1.5. To obtian more accurate results regarding the bonding strength between the old and new mortars, it is necessary to further evaluate the cohesion of C-S-H and the compactness of the new ITZ in a comprehensive manner.
dc.language	en
dc.publisher	Elsevier
dc.relation	http://purl.org/au-research/grants/arc/IH200100010
dc.relation	http://purl.org/au-research/grants/arc/DP220101051
dc.relation	http://purl.org/au-research/grants/arc/DP220100036
dc.relation	http://purl.org/au-research/grants/arc/FT220100177
dc.relation.ispartof	Construction and Building Materials
dc.relation.isbasedon	10.1016/j.conbuildmat.2023.131904
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0905 Civil Engineering, 1202 Building
dc.subject.classification	Building & Construction
dc.subject.classification	3302 Building
dc.subject.classification	4005 Civil engineering
dc.subject.classification	4016 Materials engineering
dc.title	Nano/microcharacterization and image analysis on bonding behaviour of ITZs in recycled concrete enhanced with waste glass powder
dc.type	Journal Article
utslib.citation.volume	392
utslib.for	0905 Civil Engineering
utslib.for	1202 Building
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	University of Technology Sydney/Strength - CBI - Centre for Built Infrastructure
utslib.copyright.status	closed_access	*
dc.date.updated	2024-05-07T03:59:39Z
pubs.publication-status	Published
pubs.volume	392

Abstract:

Waste glass powder (WGP) has been shown to help improve concrete properties. However, the underlying mechanism needs to be explored at the micro level, specifically on the interfacial transition zones (ITZs). This study aims to investigate the microtopography and bonding behaviours of ITZs using modelled recycled aggregate concrete (MRAC). To highlight the differences, two sets of MEAC were prepared, consisting of old and new mortars with water-cement ratios of 0.45 and 0.40, respectively. WGP was incorporaed in the new mortar, replacing 20 wt% of cement to enhance the performance of the new ITZ. Two groups of MRAC with three types of ITZs were successfully fabricated and studied. The property differences between the old ITZ, new ITZ without WGP, and new ITZ with WGP were comprehensively evaluated and compared based on phase distribution, chemical composition, and micromechanical properties. The results show that the new ITZ without WGP exhibited the highest porosity (avg. 7.29%) but a higher calcium silicate hydrate (C-S-H) elastic modulus (avg. 11.89 GPa) compared to the old ITZ (avg. 4.33% and 10.37 GPa, respectively). WGP effectively reduced the volume fraction of pores and cracks to 4.30% by reacting with calcium hydroxide (CH) within the new ITZ and the adjacent old mortar, resulting in generation of a significant amount of C-S-H gel with a Si/Ca ratio of approximately 1.5. To obtian more accurate results regarding the bonding strength between the old and new mortars, it is necessary to further evaluate the cohesion of C-S-H and the compactness of the new ITZ in a comprehensive manner.

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http://hdl.handle.net/10453/178719