Analysis of engineered cement paste using silica nanoparticles and metakaolin using 29Si NMR, water adsorption and synchrotron X-ray Diffraction

•The optimum limit of NS additives depends on the degree of NS reaction with cement.•NS limit and the amount of MK found to control the porosity of the hardened cement.•The optimum dosage of NS is governed by the polymerization reaction and porosity.•The study help’ in deciphering the role of NS for developing nano-engineered cement.