Mixed alkali regional metakaolin-based geopolymer

Abstract

In pursuit of sustainable construction, regional natural materials can be used as a base for geopolymer processing. For higher strength achievement, this study uses mixed potassium-sodium geopolymer. Geopolymer was synthesized using metakaolin produced from kaolinite extracted from Amazonian soil, and microscopically compared to a commercial, highly reactive, metakaolin-based geopolymer. Amazonian kaolin was converted into metakaolin by calcination up to 700 °C. X-ray diffraction (XRD) analysis showed the resulting amorphous metakaolin to be 76% pure, with 24% crystalline quartz impurity. Four-point flexural and compressive strength testings of the geopolymer were carried out according to ASTM standards. Scanning electron microscopy was used to investigate the microstructure and the Si/Al ratio. In addition, XRD was used to confirm the formation of geopolymer. © 2017 by The American Ceramic Society.