Tero Luukkonen, Harisankar Sreenivasan, Zahra Abdollahnejad, Juho Yliniemi, Anu Kantola, Ville-Veikko Telkki, Paivo Kinnunen, Mirja Illikainen, Influence of sodium silicate powder silica modulus for mechanical and chemical properties of dry-mix alkali-activated slag mortar, Construction and Building Materials, Volume 233, 2020, 117354, ISSN 0950-0618, https://doi.org/10.1016/j.conbuildmat.2019.117354.
Inﬂuence of sodium silicate powder silica modulus for mechanical and chemical properties of dry-mix alkali-activated slag mortar
|Author:||Luukkonen, Tero1; Sreenivasan, Harisankar1; Abdollahnejad, Zahra1;|
1Fibre and Particle Engineering Research Unit, University of Oulu, P.O. Box 4300, FI-90014, Finland
2NMR Research Unit, Faculty of Science, University of Oulu, P.O. Box 4300, FI-90014, Finland
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019110136231
|Publish Date:|| 2021-10-31
Sodium silicate powders with different SiO₂/Na₂O (silica modulus) were characterized by solubility rate, pH, and chemical structure (by ²⁹Si MAS-NMR) and compared in the preparation of one-part (or dry-mix) alkali-activated blast furnace slag mortar. The low SiO₂/Na₂O indicated the beneficial presence of less-polymerized silica (Q¹ and Q² Si environments) and thus faster dissolution. Consequently, using sodium silicates with SiO₂/Na₂O of 0.9, 2.1, and 3.4 resulted 28 d compressive strengths of 103, 80, and 2 MPa, respectively, with increasing setting time and decreasing heat release in isothermal calorimetry. Adjustment of activator SiO₂/Na₂O from 2.1 or 3.4 to 0.9 by adding NaOH powder resulted increased or decreased mechanical properties of mortar, respectively, depending on the initial silica modulus. These properties were not, however, similar to those obtained with sodium silicate having SiO₂/Na₂O of 0.9 originally. Depending on the case, the added NaOH can be consumed for dissolving sodium silicate activator, slag, or the forming (C,N)-(A)-S-H gel.
Construction & building materials
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
116 Chemical sciences
215 Chemical engineering
216 Materials engineering
This work was supported by the Finnish Funding Agency for Technology and Innovation (Tekes) (project GEOBIZ, grant number 1105/31/2016). Anu Kantola and Ville-Veikko Telkki acknowledge the financial support received from the Kvantum Institute (University of Oulu) and the Academy of Finland (grants #289649 and 294027).
|Academy of Finland Grant Number:||
289649 (Academy of Finland Funding decision)
294027 (Academy of Finland Funding decision)
© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http:/creativecommons.org/licenses/by-nc-nd/4.0/