University of Oulu

Adediran A, Yliniemi J and Illikainen M (2021) Development of Sustainable Alkali-Activated Mortars Using Fe-Rich Fayalitic Slag as the Sole Solid Precursor. Front. Built Environ. 7:653466. doi: 10.3389/fbuil.2021.653466

Development of sustainable alkali-activated mortars using Fe-rich fayalitic slag as the sole solid precursor

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Author: Adediran, Adeolu1; Yliniemi, Juho1; llikainen, Mirja1
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.8 MB)
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Language: English
Published: Frontiers Media, 2021
Publish Date: 2021-04-23


Vast amounts of water-cooled non-ferrous metallurgy slags are generated yearly, and significant amounts are unutilized or dumped in landfills. To address this issue, in this study, MgO-FeOx-SiO₂ fayalitic slag (FS) was used as the sole solid precursor (as an aggregate and binder) in alkali-activated mortars. The performance of the mortar samples was analyzed in terms of workability, density, compressive strength, and ultrasonic pulse velocity. The microstructural properties and binder composition of the samples were studied using a scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). Experimental results revealed that mortar samples made with FS aggregates performed better, achieving a 28-day compressive strength of 21 MPa compared to mortars produced with standard sand aggregates, which gained compressive strengths of 9 MPa. Further optimization of the particle size distribution of FS aggregate-based mortar samples using particle packing technology improved the workability, densified the mortar and yielded a mechanical performance of up to 40 MPa. FS aggregates have better interfacial bonding with the binder gel compared to standard sand, and the FS aggregates participate in the hardening reactions, consequently affecting the final binder phase composition, which consists of a Na₂O-Fe₂O₃-SiO₂ gel with lower quantities of CaO, MgO, and Al₂O₃. Therefore, the alkali-activated mortars produced based on the optimization of fully recycled industrial residues can provide a pathway for the sole utilization of metallurgical by-products, which can have a wide range of structural applications.

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Series: Frontiers in built environment
ISSN: 2297-3362
ISSN-E: 2297-3362
ISSN-L: 2297-3362
Volume: 7
Article number: 653466
DOI: 10.3389/fbuil.2021.653466
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
212 Civil and construction engineering
222 Other engineering and technologies
1172 Environmental sciences
218 Environmental engineering
Funding: This work was done as a part of the GEOBOT project supported by the European Regional Development Fund (ERDF), Pohjois-Pohjanmaa Council of Oulu Region and various companies (Boliden Harjavalta Oy, Keliber Oy, and Saint Gobain Finland Oy). AA received funding from the K. H. Renlund Foundation and Finnish Cultural Foundation toward his doctoral research. JY received funding from the Academy of Finland (grant number 322786).
Academy of Finland Grant Number: 322786
Detailed Information: 322786 (Academy of Finland Funding decision)
Copyright information: © 2021 Adediran, Yliniemi and Illikainen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.