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A study on the influencing parameters in developing construction and demolition waste-based geopolymer concretes and their sustainability assessment
Alhawat, Musab Yildirim, Gurkan Ozcelikci, E. Aldemir, A.
Alhawat, Musab
Yildirim, Gurkan
Ozcelikci, E.
Aldemir, A.
Publication Date
2024-05-03
End of Embargo
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(c) 2024 The Authors. This is an Open Access article distributed under the Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0/)
Peer-Reviewed
Yes
Open Access status
openAccess
Accepted for publication
2024-04-03
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Abstract
Construction and demolition waste (CDW) has been recently identified as a potential aluminosilicate source for geopolymers. However, the available research has mainly focused on developing CDW-based geopolymer pastes and mortars, while studies on geopolymer concretes sourced from CDW have been very limited. Thus, the current study aimed at experimentally identifying different CDW materials suitable for producing geopolymer concretes. Additionally, the study analysed the mechanical, microstructural, and environmental properties of CDW- based geopolymer concrete produced. In this regard, the effect of relevant parameters on the compressive strength development of CDW-based geopolymer concretes was comprehensively investigated, including those related to precursor types/fineness, alkali activator solution, aggregate type/size and curing regimes. Microstructural analyses were also conducted on the selected samples (100% brick waste, 100% tile waste, 100% concrete waste and 75% brick waste + 25% GGBS). Finally, the environmental impact of geopolymer concrete was assessed and compared with similar traditional concrete. Results showed that employing CDWs alone is not suitable to achieve sufficient strengths under all curing regimes. However, the inclusion of 25% GGBS significantly improved the strength performance of CDW-based geopolymer concrete, in comparison to other supplementary cementitious materials (SCMs) such as Class-C fly ash and calcium hydroxide. The particle size of CDWs and concentration of alkaline activators highly affect the performance of CDW-based geopolymer concretes. Utilization of CDWs with particles finer than 75 μm and high concentrations of NaOH (12 M) is recommended to achieve good performance. The results also indicate that almost similar energy is needed for producing CDW-based geopolymer and OPC-based traditional concrete, whereas a huge reduction in CO2 emission (∼40%) was estimated in the case of geopolymers. The outcomes of the current study are expected to contribute to the advancement of geopolymer concrete derived from CDW in addition to providing valuable insights into this type of concrete for practitioners and academics.
Version
Published version
Citation
Alhawat M, Yildirim G, Ashour A et al (2024) A study on the influencing parameters in developing construction and demolition waste-based geopolymer concretes and their sustainability assessment. Construction and Building Materials. 426: 136143.
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Article