Nano Fumed Silica Particles on Cement Properties

Abstract

The hydration of cement paste is generally responsible for the development of essentially every engineering property of cement paste. The compressive strength and early hydration performance of cement mortar can be improved by adding nano silica into ordinary strength mortar, which is related to the pozzolanic properties of nano silica. Hence, this paper investigated the effects of different amounts (2%, 4% and 6%) of fumed silica on hydration and hardening of cement. The result indicates that water consumption of standard consistency of cement increases with the addition of nano fumed silica particles. In addition, with the dosage increase of fumed silica, the setting time gradually becomes shorter. It is worth noting that the setting time of slurry becomes shorter obviously when the addition amount of nano fumed silica is 2%. The result of cement sand test indicates that the addition of fumed silica reduces the strength of cement, which is related to the hydration reaction. It is suggested that nano fumed silica should be used in combination with high efficient plasticizer, which decreases the agglomeration and directly impacts kinetics of hydration and leads to improvement in workability as well as concrete strength through the increase in the formation of silicate calcium hydrate.