Polycarboxylate / nanosilica modified quaternary cement formulations - enhancements and limitations

Styliani Papatzani, Kevin Paine

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The effect of polycarboxylate / nanosilica (nS) particles in quaternary cement
formulations comprising of Portland cement (PC), limestone powder (LS) and fly ash (FA) was investigated for the first time. The reference formulation, contained 60% PC, 20% LS and 20% FA by mass of binder in an effort to minimize clinker and maximize other constituents. nS particles were characterized via transmission and X-ray scanning electron microscopy. Nanosilica was added at a 0.3 or 0.6% by mass as a partial replacement of PC and different water-to-binder (w/b) ratios were explored. Compressive strength tests and thermal gravimetric analyses (TGA) performed at day 7, 28 and 56 testified to pozzolanic behavior. Results suggest a mechanism of "deactivation" of some FA particles with age. A new ratio; [(compressive strength in MPa)/(calcium hydroxide content detected by TGA)] was introduced, correlating microscale characteristics (hydration products) and macroscale performance (delivered compressive strengths).
Back scattered SEM images confirmed the C-S-H network formation, the presence of reacted/unreacted FA particles, and the availability of Ca(OH)2 for delayed hydration reactions. Tests on mortars also confirmed the enhancement offered by nS addition. The lower bound nS addition was determined to be 0.6% by mass of binder for pastes and 0.5% for mortars.
LanguageEnglish
Article number17.00111
Pages256-269
JournalAdvances in Cement Research
Volume30
Issue number6
Early online date6 Nov 2017
DOIs
StatusPublished - 1 Jun 2018

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Coal Ash
Fly ash
Cements
Portland cement
Compressive strength
Binders
Calcium Carbonate
Limestone
Mortar
Hydration
Powders
Calcium Hydroxide
Scanning electron microscopy
Hydrated lime
Adhesive pastes
Ointments
Availability
X rays
Water
Hot Temperature

Cite this

Polycarboxylate / nanosilica modified quaternary cement formulations - enhancements and limitations. / Papatzani, Styliani; Paine, Kevin.

In: Advances in Cement Research, Vol. 30, No. 6, 17.00111, 01.06.2018, p. 256-269.

Research output: Contribution to journalArticle

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