Effect of nano silica (SiO2) on the hydration kinetics of cement

Taher Abu-Lebdeh, Relly Victoria Virgil Petrescu, Moayyad Al-Nasra, Florian Ion Tiberiu Petrescu

Abstract


This study investigated the influence of adding
nano silica (SiO2) on the cement hydration
process, particularly on the formation of calcium
silicate hydrate (C-S-H) at different stages of
hydration. The study investigated the effect of
adding nano-silica on the mechanical properties
of the hardened cement corresponding to the
formation of C-S-H during the hydration process
of a cement paste. Specimens made up of four
different percentage of nano silica (0%, 1%, 3%
and 5%) were tested at different stages of
hydration ranging from 3 to 56 days. The effect of
nano-silica on the compressive strength, stressstrain,
and elastic modulus of nano-cement was
examined using MTS and Forney testing
machines. The signature phase and formation of
C-S-H and calcium hydroxide (CH) were
monitored using Fourier Transform Infrared
Spectroscopy (FTIR) and Scanning Electron
Microscopy (SEM). The study also investigated the
effect of curing method (vacuum and water curing)
on the strength development. The experimental
results show that the formation of calcium silicate
hydrate (C-S-H) increases significantly during the
early stages of hydration which correspond to the
drastic increase in compressive strength. The
formation of C-S-H continues to increase
throughout the 56 days but at a moderate rate. The
results reveal that 1% of nano silica by volume of
cement is the optimum ratio that yields the
maximum strength. The results also indicated that
the strength of the traditional water cured
specimens were higher than that of vacuum cured
specimens.


Keywords


nano silica; hydration kinetics; electron microscopy; calcium hydroxide

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ISSN 1330-9587 (Print), ISSN 1849-0433 (Online)

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