Whether do nano-particles act as nucleation sites for C-S-H gel growth during cement hydration?

Deyu Kong*, Senle Huang, David Corr, Yang Yang, Surendra P. Shah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

In this study, three modelling experiments were designed to investigate whether nano-particles incorporated in the cement paste act as nucleation sites for C–S–H gel growth during cement hydration. The nano-particles with (nano-SiO2) and without (nano-TiO2) pozzolanic reactivity were used. In the first experiment, both the cement and nano-particles were dispersed in water to prepare dilute cement paste, in which the cement and nano-particles can contact each other. In the second one, the cement particles were laid inside a filter paper funnel and immersed in tap and ultrapure water with nano-particles dispersed, in order to separate the cement particles with nano-particles by using the filter paper. In the third one, large clinker particle was embedded in resin, surface-polished and then exposed upside down in ultrapure water with and without nano-particles dispersed. After hydration for 7 days, the hydration products in the paste or the nano-particle dispersion were observed by using TEM and the hydrated surface of the embedded clinkers were detected by using SEM. Based on the experimental results and the detailed discussions by using the classic nucleation theory, it was found that there may have no nucleus function of the nano-particles for the C–S–H gel precipitation during cement hydration, at least in the hydrating system with nano-silica and nano-TiO2 addition. It was proposed to more reasonably explain the observations in the three modelling experiments by using the topochemical reaction instead of the through-solution mechanism for the C–S–H gel formation.

Original languageEnglish (US)
Pages (from-to)98-109
Number of pages12
JournalCement and Concrete Composites
Volume87
DOIs
StatePublished - Mar 2018

Keywords

  • C-S-H gel
  • Cement hydration
  • Morphology
  • Nano-particle
  • Seeding effect
  • Topochemical

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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