Engineering aluminosilicates with high surface area extracted from waste concrete to form a viable supplementary cementitious material
File(s)
Published version
Author(s)
Ding, Tiejun
Zhang, Suyang
Yio, Marcus
Wong, Hong
Cheeseman, Christopher
Type
Journal Article
Abstract
Aluminosilicate residues can be produced by acid leaching waste concrete. These are pozzolanic and have the potential to be used as a supplementary cementitious material (SCM). However, the workability of cement mixes is seriously compromised when aluminosilicate particles are used, due to their high surface area and excessive water absorption. This negatively influences the compaction and performance of mixes. In this work, aluminosilicates extracted from waste concrete have been heat-treated, and the effects of temperature on their specific surface area, pozzolanic reactivity, and consequently the workability and strength of mortars are reported. Thermal treatment at 900℃ for 1 hour reduces the specific surface area of aluminosilicate particles to values comparable to commercial SCMs such as coal fly ash (FA) and ground granulated blast furnace slag (GGBFS), while retaining significant pozzolanic activity. Mortars containing CEM I replaced by 20 wt% of optimally heat-treated aluminosilicate residue at a 0.56 w/b ratio show improved flow properties compared to untreated residues, and similar compressive strength to mortars containing the same amount of silica fume (SF) or GGBFS. The research shows that aluminosilicates extracted from cement paste can be heat treated to form a viable SCM, and this contributes to the future development of circular concrete.
Date Issued
2025-02-07
Date Acceptance
2025-01-11
Citation
Construction and Building Materials, 2025, 462
ISSN
0950-0618
Publisher
Elsevier BV
Journal / Book Title
Construction and Building Materials
Volume
462
Copyright Statement
© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1016/j.conbuildmat.2025.139981
Publication Status
Published
Article Number
139981
Date Publish Online
2025-01-16