Effects of colloidal nanoSiO 2 on fly ash hydration

Pengkun Hou, Kejin Wang, Jueshi Qian*, Shiho Kawashima, Deyu Kong, Surendra P. Shah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

139 Scopus citations

Abstract

The influences of colloidal nanoSiO 2 (CNS) addition on fly ash hydration and microstructure development of cement-fly ash pastes were investigated. The results revealed that fly ash hydration is accelerated by CNS at early age thus enhancing the early age strength of the materials. However, the pozzolanic reaction of fly ash at later age is significantly hindered due to the reduced CH content resulting from CNS hydration and the hindered cement hydration, as well as due to a layer of dense, low Ca/Si hydrate coating around fly ash particles. The results and discussions explain why the cementitious materials containing nanoSiO 2 had a lower strength gain at later ages. Methods of mitigating the adverse effect of nanoSiO 2 on cement/FA hydration at later ages were proposed.

Original languageEnglish (US)
Pages (from-to)1095-1103
Number of pages9
JournalCement and Concrete Composites
Volume34
Issue number10
DOIs
StatePublished - Nov 2012

Keywords

  • Coating
  • Fly ash
  • Hydration
  • Morphology
  • Nanosio

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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