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Development of alkali-activated magnesium aluminosilicate binders from soap- stone

Author(s): Z. Abdollahnejad, T. Luukkonen, M. Mastali, J. Yliniemi J, P. Kinnunen, M. Illi-kainen
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 361-368
Total Pages: 8
Language : English

Abstract: Soapstone plays an important role in the economy of many countries and it is mainly used for architectural applications, such as counter tops and floor tiles. However, the extraction processing of soapstone stone can generate a large amount of waste powder, which represents disposal problems and environmental damages.
To minimize its negative environmental impacts, it would be useful to develop new technique to reuse these industrial wastes in construction applications and minimise their negative environmental effects.
This paper presents the experimental results regarding the use of soapstone as a precursor for alkali-activated materials. Based on earlier published results, the main component of soapstone, talc (Mg3Si4O10(OH)2), is poorly reactive in alkali-activation due to its chemical structure and a lack of amorphous components. Consequently, mechanical properties of these materials are mostly too low to be used in the construction applications. Thus, these materials require co-binder, high temperature curing and high alkalinity to achieve high strength alkali- activated material.
In this study, the blended soapstone/metakaolin binders were activated by using an alkali solution, which consists of sodium hydroxide (10 M) and sodium silicate (molar ratio of SiO2/Na2O = 2.5). The specimens were cured by using the thermal curing (60°C) during the first 24 hours and then they were exposed to the controlled environmental conditions (23°C and 35% RH).
The results showed that substitution of soapstone by metakaolin up to 20 wt.% results in increased compressive strength to above 30 MPa after 28 days. This strength facilitates the application of the proposed binders for construction applications.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00

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