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Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders

The use of alkali activated geopolymer binders in the recent years has received much attention because of their outstanding mechanical properties, reduction of CO2 emissions and low energy for production. While number of researches are being done to develop geopolymer binders, their application is still limited. Efflorescence phenomena is one of the limitations of the extensive use of geopolymers. The efflorescence not only affect the materials aesthetics, but it also affects its mechanical performance. The present study outlines the general features of efflorescence, including its formation mechanism, chemical and mineralogical composition. Natural pozzolan from Songwe – Mbeya, Tanzania, calcium hydroxide, sodium silicate and sodium hydroxide were used as raw materials for geopolymerization process. It has been observed that efflorescence is formed on alkali activated paste specimens which were partially soaked in water. The formation of efflorescence products is formed due to unbalanced concentration of alkaline solution within the specimen. The produced efflorescence powders were tested for chemical and mineralogical compositions. The chemical composition test results indicated the significant percent increase of Na2O for efflorescence powder. This may be due to migration of Na+ from the interior of specimen to the surface during efflorescence formation. The efflorescence powder which was tested for mineralogical composition, indicated the present of some amount of calcite, mica, sodium carbonate hydrate and quartz. One of the control process of efflorescence formation on alkali activated geopolymer specimens is by maintaining equilibrium of alkali concentration within the specimens during curing process.

Efflorescence, Geopolymer Binder, Sodium Silicate, Alkali Metals, Oxide Compounds, Chemical Composition, Natural Pozzolan, Alkali Activated Materials

APA Style

Asson Sifueli Malisa, Duwa Hamisi Chengula. (2023). Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders. American Journal of Polymer Science and Technology, 9(2), 14-20.

ACS Style

Asson Sifueli Malisa; Duwa Hamisi Chengula. Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders. Am. J. Polym. Sci. Technol. 2023, 9(2), 14-20. doi: 10.11648/j.ajpst.20230902.11

AMA Style

Asson Sifueli Malisa, Duwa Hamisi Chengula. Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders. Am J Polym Sci Technol. 2023;9(2):14-20. doi: 10.11648/j.ajpst.20230902.11

Copyright © 2023 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License ( which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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