Enhancing cement hydration with nanosilica-coated polystyrene microspheres

Nanoparticles (NPs) can be used as useful additives in construction materials. In this work, nanosilica (NS) was used in a way that prevented agglomeration of NPs as a pozzolanic material to improve Portland cement hydration and thus improve the properties of concrete. The effects of NS and polystyrene (PS) microspheres coated with NS (PS@NS) on cement paste properties were examined. Spherical PS particles were prepared by dispersion polymerisation of styrene in polar solvents and characterised by Fourier transform infrared spectroscopy and environmental scanning electron microscope. The PS@NS were synthesised using the Stöber method. Analysis showed that an amorphous NS layer was deposited uniformly on the PS particles and the core/shell structure reduced the aggregation of the NS effectively. It was also found that, compared with cement paste blended with NS, the PS@NS improved cement hydration due to the agglomeration affect.