Volume stability of calcium-silicate-hydrate/polyaniline nanocomposites in aqueous salt solutions

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.14359/51687127
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Name affiliation
  1. National Research Council of Canada. Construction
FormatText, Article
Journal titleACI Materials Journal
ISSN0889-325X
Volume111
Issue6
Pages623–632
Subjectadditives; calcium; durability; gravimetric analysis; hydration; nanocomposites; phase stability; polyaniline; scanning electron microscopy; silicate minerals; thermogravimetric analysis; X-ray diffraction; aqueous salt solution; calcium silicate hydrate; crystalline structure; longitudinal expansions; NaCl aqueous solution; thermal gravimetric analysis; volume stability
Abstract
The volume stability of phase pure calcium-silicate-hydrates (C-S-H) and C-S-H/polyaniline nanocomposites prepared with two CaO-SiO2 molar ratio (C/S) variations (0.8 and 1.2) was assessed in MgSO4, MgCl2, LiCl, and NaCl aqueous solutions. The change in the crystalline structure of the samples with the time of immersion was also explored using X-ray diffraction, scanning electron microscopy, and thermal gravimetric analysis techniques. It was observed that the modification of the C-S-H samples with polyaniline significantly enhanced their volume stability and durability in all the salt solutions. The beneficial effect of the polyaniline modification was more pronounced in the C-S-H host with higher C/S (C/S = 1.2). The longitudinal expansion of the C-S-H/polyaniline nanocomposites with C/S = 1.2 in the salt solutions was about 30% of that of the phase pure C-S-H with a similar C/S ratio. In addition, the polyaniline modification of C-S-H samples reduced the rate of formation of gypsum, brucite, and other reaction products in the samples.
Publication date
PublisherAmerican Concrete Institute
LanguageEnglish
Peer reviewedYes
NPARC number21275452
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Record identifier76105c5a-123f-4bef-aff2-27b657c47da3
Record created2015-07-14
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