University of Oulu

Luukkonen, T., Abdollahnejad, Z., Yliniemi, J., Mastali, M., Kinnunen, P., & Illikainen, M. (2019). Alkali-activated soapstone waste - Mechanical properties, durability, and economic prospects. Sustainable Materials and Technologies, 22, e00118.

Alkali-activated soapstone waste - mechanical properties, durability, and economic prospects

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Author: Luukkonen, Tero1; Abdollahnejad, Zahra1; Yliniemi, Juho1;
Organizations: 1University of Oulu, Fibre and Particle Engineering Research Unit, P.O. Box 8000, FI-90014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.5 MB)
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Language: English
Published: Elsevier, 2019
Publish Date: 2019-08-07


Soapstone is a soft, magnesium-rich mineral widely used in the production of carved objects and architectural elements, for instance. The processing of soapstone causes the formation of significant amounts of waste powder, which is largely landfilled at the moment. The aim of the present study is to evaluate the suitability of soapstone waste as the main binder for the alkali-activation process using sodium silicate and hydroxide solutions as activators. The results demonstrate that soapstone alone reacts to some extent (compressive strength of 13 MPa at 28 day age), but mechanical properties are improved significantly after replacing 20% of soapstone by metakaolin (compressive strength of 31 MPa at 28 d age). The obtained mechanical properties are closely similar to those of virgin soapstone. Durability properties of the developed alkali-activated binders were similar or better than typical Portland cement-based binders in terms of high temperature, acid, and freeze-thaw resistance, and sorptivity. The material costs alkali-activated soapstone mortar were estimated as approximately 70 €/t. Thus, the results enable utilizing currently underexploited soapstone waste in a sustainable and economically interesting way.

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Series: Sustainable materials and technologies
ISSN: 2214-9937
ISSN-E: 2214-9937
ISSN-L: 2214-9937
Volume: 22
Article number: e00118
DOI: 10.1016/j.susmat.2019.e00118
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
212 Civil and construction engineering
215 Chemical engineering
Funding: This work was supported by the Finnish Funding Agency for Technology and Innovation (Tekes) (project GEOBIZ, grant number 1105/31/2016) and by the Academy of Finland (grant #292526: Novel synthesis methods for porous ceramics from mine tailings (CERATAIL)).
Academy of Finland Grant Number: 292526
Detailed Information: 292526 (Academy of Finland Funding decision)
Copyright information: © 2019 The Authors. Published by Elsevier B.V. This is anopen access article under the CC BY-NC-ND license (