aalto1 untyped-item.component.html
Hydrophobized Iron Tailings-Based Cementitious Composites for External Applications
Loading...
Access rights
openAccess
acceptedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Date
Department
Major/Subject
Mcode
Degree programme
Language
en
Pages
12
Series
Journal of Materials in Civil Engineering, Volume 37, issue 8
Abstract
The use of waste iron ore tailings (IOT) in concrete production possesses a relatively high carbon footprint during preprocessing, has associated issues of leaching and performs poorly in severe environments due to its hydrophilicity. This proof-of-concept study aims to develop hydrophobized IOT by coating it with stearic acid. The hydrophobized iron tailings (HIT) are utilized as a pore filling material to develop hydrophobic concrete for low to medium load bearing applications. The HIT as an additive was studied at 30%, 40%, 50%, and 60% (filler to sand ratio by weight) amendment rates to produce cementitious composites in parallel with conventionally used fly ash (FA) and hydrophobized fly ash (HFA). The results revealed that both HIT and HFA when used as pore fillers could render the final cementitious blocks hydrophobic due to visible impregnation of hydrophobic surface functional groups ( CH3, CH2) with a mean contact angle between 120° and 143°. Consequently, the 24-h water absorption of these hydrophobized mortars under submerged conditions decreased by 87%, with respect to the conventional FA-based blocks. At 30% amendment, the near-superhydrophobic HIT-based blocks had the highest 28-day compressive strength at 18 MPa among all tested blocks. This is primarily attributed to the pore filling effects and high calcium-silica-hydrate formation. At application rates higher than 30%, the strength reduced considerably (around 7 MPa at 60% application rate) due to the dissolution of hydrated calcium hydroxide [Ca(OH)2] when it reacts with the stearic acid of the coating. Nevertheless, based on mechanical strength properties and water absorption measurements of HIT blocks, it can be inferred that these hydrophobic mortars could be used in a range of applications, such as mine backfilling material or as pedestrian blocks for municipality development. This would likely be more durable against moisture-based attacks under severe environments (freeze-Thaw and extreme pH).
Description
Publisher Copyright: © 2025 American Society of Civil Engineers.
Other note
Citation
Roy, S, Chah, C N, Banerjee, A, Bordoloi, S & Sekharan, S 2025, 'Hydrophobized Iron Tailings-Based Cementitious Composites for External Applications', Journal of Materials in Civil Engineering, vol. 37, no. 8, 04025231. https://doi.org/10.1061/JMCEE7.MTENG-18706