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http://dx.doi.org/10.7844/kirr.2018.27.6.59

Influence of Na/Al Ratio and Curing Temperature of Geopolymers on Efflorescence Reduction  

Kim, Byoungkwan (Resources Recycling, University of Science & Technology)
Heo, Ye-Eun (Department of Geoenvironmental Sciences, Kongju National University)
Chon, Chul-Min (Geological Environment Division, Korea Institute of Geoscience and Mineral Resources)
Lee, Sujeong (Resources Recycling, University of Science & Technology)
Publication Information
Resources Recycling / v.27, no.6, 2018 , pp. 59-67 More about this Journal
Abstract
Efflorescence is a white deposit of powders in the surface of cement concrete which can also occur in geopolymers. Efflorescence occurs when sodium ions in alkali activator react with atmospheric carbon dioxide to form sodium carbonate components. In this study, we investigated whether the secondary efflorescence can be reduced by controlling the Na/Al mole ratio or by changing the curing temperature and heat curing time in fly ash-based geopolymers. The 28 days compressive strength in geopolymers having Na/Al ratio of 1.0 was higher than geopolymers having Na/Al ratio of 0.8. The strength increased with the increasing curing temperature and longer heat curing time. On the other hand, efflorescence was lower when the curing temperature was high and the heat curing time was longer in the geopolymers having Na/Al ratio of 1.0. The geopolymers having Na/Al ratio of 0.8 showed accelerated efflorescence occurrence than the geopolymers having Na/Al ratio of 1.0. In order to reduce the occurrence of the secondary efflorescence of fly ash-based geopolymers, it will be advantageous to maintain the Na/Al ratio at 1.0, increase the curing temperature, and lengthen the heating curing time.
Keywords
fly ash; geopolymer; efflorescence; curing; compressive strength;
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Times Cited By KSCI : 2  (Citation Analysis)
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