Effect of the reagglomeration process of multi-walled carbon nanotubes dispersions on the early activity of nanosilica in cement composites

This work studies the effect of the reagglomeration process of Multi-Walled Carbon Nanotubes (MWCNT) dispersions on the activity of silica nanoparticles at early ages when they are combined in cement matrixes. MWCNT/water/superplasticizer dispersions were produced via sonication and combined with nanosilica particles in the mixing water of the cement samples. X-ray diffraction, isothermal calorimetry, thermogravimetric and mechanical strength analysis were carried out to identify variations in the hydration reaction induced by the combination of these nanoparticles. It was found that the early activity of the nanosilica (NS) is accelerated, decelerated or completely inhibited by the reagglomeration process of the MWCNT dispersions, depending on MWCNT and Ca(OH)2 amounts in the media.