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Small Changes Can Make a Great Difference Gaitero, Juan J ; Campillo, Igor ; Mondal, Paramita ; Shah, Surendra P

By: Contributor(s): Series: Transportation Research Record: Journal of the Transportation Research Board ; 2141Publication details: Washington DC Transportation Research Board, 2010Description: s. 1-5ISBN:
  • 9780309142762
Subject(s): Bibl.nr: VTI P8167:2141Location: TRBAbstract: Four different types of commercially available silica nanoparticles were added to ordinary portland cement pastes to study their effects. The subsequent multiscale characterization of the material revealed that the addition of the nanoparticles induced a pozzolanic reaction that increased the amount of calcium silicate hydrate (C-S-H) gel in the paste to the detriment of portlandite. This had important implications for the hydration kinetics and the microstructure of the paste, including an increase in the initial hydration rate. A reduction of the overall porosity was also observed. The C-S-H gel of the pastes with nanosilica also showed some particular features, such as greater aluminum content and longer silicate chains. This was especially relevant because nanoindentation measurements and atomistic calculations showed that this was bound to an improvement in the mechanical properties of the C-S-H gel itself. Finally, the sum of all these factors resulted in pastes with 30% more compressive strength, which proved that, effectively, small changes can make a great difference.
Item type: Reports, conferences, monographs
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Current library Status
Statens väg- och transportforskningsinstitut Available

Four different types of commercially available silica nanoparticles were added to ordinary portland cement pastes to study their effects. The subsequent multiscale characterization of the material revealed that the addition of the nanoparticles induced a pozzolanic reaction that increased the amount of calcium silicate hydrate (C-S-H) gel in the paste to the detriment of portlandite. This had important implications for the hydration kinetics and the microstructure of the paste, including an increase in the initial hydration rate. A reduction of the overall porosity was also observed. The C-S-H gel of the pastes with nanosilica also showed some particular features, such as greater aluminum content and longer silicate chains. This was especially relevant because nanoindentation measurements and atomistic calculations showed that this was bound to an improvement in the mechanical properties of the C-S-H gel itself. Finally, the sum of all these factors resulted in pastes with 30% more compressive strength, which proved that, effectively, small changes can make a great difference.