Yes / Degrading infrastructure and applications of structural demolition create
tremendous amounts of construction and demolition waste (CDW) all around
the world. To address this issue in an effective way, recycling CDW in a most appropriate
way has become a global concern in recent years. To this end, this study
focused on the valorization of CDW-based materials such as tile, bricks, glass,
and concrete in the development of geopolymer mortars. CDWs were first collected
from demolition zone and then subjected to crushing-milling operations. To
investigate the influence of slag (S) addition to the mixtures, 20% S substituted
mixture designs were also made. Fine recycled concrete aggregates (FRCA) obtained
from crushing and sieving of the waste concrete were used as the aggregate.
A series of mixtures were designed using different proportions of three distinct
alkali activators such as sodium hydroxide (NaOH), sodium silicate (Na2SiO3),
and calcium hydroxide (CH; Ca(OH)2). To improve their applicability, the mixtures
were left to cure at room temperature rather than the heat curing which
is frequently applied in the literature. After 28 days ambient curing, the 100%
CDW-based geopolymer mortar activated with three different activators reached
a compressive strength of 31.6 MPa, whereas the 20% S substituted geopolymer
mortar showed a 51.9 MPa compressive strength. While the geopolymer mortars
activated with only NaOH exhibited poor performance, it was found that the
use of Na2SiO3 and CH improved the mechanical performance. Main geopolymerization
products were related to NASH (Sodium alumino-silicate hydrate),
CASH (Calcium alumino-silicate hydrate), and C(N)ASH gel formations. Results
demonstrated that mixed CDWs can be employed in the manufacturing
geopolymers, making them potential alternatives to Portland cement (PC)-based
systems by being eco-friendly, energy-efficient, and comparable in compressive
strength. / This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/19679 |
| Date | 22 September 2023 |
| Creators | Yildirim, Gurkan, Ashour, Ashraf, Ozcelikci, E., Gunal, M.F., Ozel, B.F., Alhawat, Musab M. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Published version |
| Rights | © 2023 Yildirim et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CCBY) (http://creativecommons.org/ licenses/by/4.0/) which permits commercial use, including reproduction, adaptation, and distribution of the article provided the original author and source are credited. Published by United Scientific Group., CC-BY |
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