Study of durability of Portland cement mortars blended with silica nanoparticles

In this paper the effects of nanosilica (NS) on porosity, capillary suction (UNE 8398:2008), compressive strength (ASTM C 349), and sulfate resistance (ASTM C 1012) were evaluated for mortars made with Portland cement (control) and partially replaced with a commercial NS suspension, in percentages by weight of 0%, 1%, 3%, 5%, and 10%. Mortars with a water/binder (w/b) ratio of 0.55 and addition of superplasticizer, for flow correction, were prepared. NS showed that, it has an important role in pore refining, decreasing the total volume of pores and their diameters. Samples containing NS showed an important positive effect on the capillary suction and sulfate resistance. In the case of expansion due to sulfate attack, mortars with 5% and 10% of NS decreased expansion by 90% and 95% respectively after 2 years of immersion.