Multi-scale analysis of cement pastes with nanosilica addition

The effect of the addition of nanosilica on the properties of cement pastes after 28 d of hydration was studied in a multi-scale approach through X-ray diffraction, thermal analysis, nitrogen adsorption analysis, infrared spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and compressive strength tests. The results showed an increase in strength resulting from the pozzolanic nature of the nanosilica, the reduction and refinement of the paste porosity and also the increase of the of calcium-silicate-hydrate gel polymerisation with the addition. Furthermore, NMR spectra suggested that the presence of nanosilica produces an inclusion of the Al³⁺ ion in the gel structure.