Investigation on the microstructure of alkali-activated mixed slag by SEM and SSNMR

Wen Huan Zhong, Wei Hsing Huang

Research output: Contribution to journalArticlepeer-review

Abstract

Alkali-activated mixed slag is a binder made by mixing blast furnace slag and ladle slag and activated using alkali activator. The binder exhibits good strength development and better resistance to chemical attack than ordinary Portland cement, thus shows potential in making green concrete. In this study, the mixed slag was produced by blast furnace slag and ladle slag mix at a specific weight percent and then activated by an alkali activator prepared by liquid sodium silicate and sodium hydroxide. The microstructure of alkaliactivated mixed slag paste was observed by scanning electron microscopy (SEM) and solid-state nuclear magnetic resonance spectroscopy (SSNMR). The results show that hydration products of alkali-activated mixed slag are amorphous and become more dense in structure with time and concentration of activator. Aluminum ion combines silicon ion or compound and produces C-AS-H gel with low Ca/Si ratio. The aluminum ion is in the inner portion of the gel, hence chemical attacks against aluminum ions and compounds become difficult to effect. This in turn explains why alkali-activated binder shows improved resistance to chemical attacks.

Original languageEnglish
Pages (from-to)37-46
Number of pages10
JournalJournal of the Chinese Institute of Civil and Hydraulic Engineering
Volume29
Issue number1
DOIs
StatePublished - 1 Mar 2017

Keywords

  • Alkali-activated mixed slag
  • Scanning electron microscopy(SEM)
  • Solid-state nuclear magnetic resonance spectroscopy(SSNMR)

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