Development of alkali-activated binder using hwangtoh without calcination

Baek Joong Kim, Chongku Yi, Kyung In Kang

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


In terms of flow and compressive strength, we examined natural hwangtoh, a readily available eco-friendly material mineralogically similar to kaolin, as a possible alkali-activated binding material. The phase and molecular structures of hwangtoh before and after alkali activation were analyzed by X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (NMR). The sample prepared by mixing hwangtoh with 10 M sodium hydroxide and sodium silicate solutions at 0.45 and 0.10 by weight of hwangtoh, respectively, gave the highest compressive strength of 25.4 MPa and a flow value of 50%. The results of the XRD analysis were consistent with the results of 29Si solid-state NMR analysis, which showed that local environments of the 29Si nucleus in hwangtoh transformed from Q3(0Al) to Q3(1Al) and Q 4 in the amorphous phase during the alkali-activation process. The newly formed reaction products filled the pores and densified the matrix, improving the compressive strength of the alkali-activated hwangtoh paste.

Original languageEnglish
Pages (from-to)206-213
Number of pages8
JournalConstruction and Building Materials
Publication statusPublished - 2014 May 15

Bibliographical note

Funding Information:
“This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (2011-0004787). In addition, in part, this research was supported by a Korea University grant. Furthermore, this study made use of the KBSI NMR and SEM facility at Seoul, Korea.”


  • Alkali activation
  • Hwangtoh
  • Physical properties
  • Si solid-state NMR
  • XRD

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science


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