Chloride binding ability and the onset corrosion threat on alkali-activated GGBFS and binary blend pastes

Abstract

This paper presents an experimental study to investigate the chloride binding ability of alkali-activated ground granulated blast furnace slag (GGBFS) and binary blend pastes. Free chloride and total chloride were measured to assess the chloride binding ability. pH measurement was performed to obtain [Cl⁻/OH⁻] ratio to assess the onset corrosion threat. The results showed that bound chloride significantly increased in GGBFS pastes and it gradually increased with GGBFS content in the binary blends. GGBFS paste mixed with deionised water and binary blend pastes showed corrosion risks although their free chloride contents were significantly low. The results further demonstrated that Ordinary Portland cement may be a more appropriate option than NaOH for activating GGBFS in terms of corrosion resistance.

Keywords:

• alkali-activated GGBFS
• chloride binding
• [Cl⁻/OH⁻] ratio
• hydrotalcite
• corrosion

Acknowledgement

The authors would like to acknowledge the continuous supports from the University of New South Wales, Canberra throughout this research.