Characteristics of surface-treatment of nano-SiO2 on the transport properties of hardened cement pastes with different water-to-cement ratios

Pengkun Hou, Xin Cheng*, Jueshi Qian, Rui Zhang, Wei Cao, Surendra P. Shah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

A reduced transport property of the superficial part of concrete structures is beneficial for enhancing their durability, due to the blocking of the migration of aggressive agents. In this study, influences of colloidal nano-SiO2 (CNS) with a mean particle size of 20 nm and its precursor, tetraethoxysilane (TEOS), on the transport properties of hardened cement pastes with water-to-cement ratios of 0.26, 0.38, 0.60 and 1.0 by mass were investigated by measuring the water absorption ratio and water vapor transmission coefficient, after the samples were first soaked in treatment agents for 1 h. Results showed that CNS and TEOS are capable of reducing the transport properties of hardened cement pastes by altering the pore structures. CNS reduces the threshold value and volume of the pores larger than about 0.1 μm, while TEOS reduces the threshold value and volume of the pores smaller than 0.1 μm, and TEOS also reduces the ratio of the 'ink-bottle' pore volume to the throat pore volume to a greater extent. A linear relationship between the volume of capillary pores smaller than 0.1/0.01 μm and the transport property was found, which can be ascribed to the reduction of transport properties of hardened cement pastes after surface-treatment with CNS or TEOS.

Original languageEnglish (US)
Pages (from-to)26-33
Number of pages8
JournalCement and Concrete Composites
Volume55
DOIs
StatePublished - Jan 2015

Keywords

  • Cement paste
  • Surface treatment
  • Tetraethoxysilane (TEOS)
  • Transport property

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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