CONCRETE

[:ru]Пекмезси Б.[:en]Pekmezci, B. Y.[:] [:ru]Факультет гражданского строительства, Стамбульский технический университет, Турция[:en]Faculty of Civil Engineering, Istanbul Technical University, Turkey[:]

Alitinform №2 (24) 2012 г. 62-70 p.

Abstract

In today’s concrete technologies, mineral additives are widely used in order to improve many properties of concrete. The most preferred mineral additives for reducing the cost of cement in concrete mixtures are fly ash, which is a by-product of thermal power-plants that is classified as artificial pozzolans, and ground granulated blast-furnace slag. Some loss of strength is obtained in mineral admixture concretes compared to Portland cement concretes. Therefore, a high contribution rate of mineral additives in mixtures by replacement of cement is limited. In this experimental study, we examine whether the loss of strength in early ages of mortars containing fly ash and ground granulated blast furnace slag can be prevented by using synthetic nano-silica (nano-SiO₂). The effects of nano-silica on the hydration kinetics have been tried in order that they be experimentally determined. The general conclusion of the study was that: nano-silica does not have a significant effect on Portland cement strength gain in early ages; the low usage rates of nano-silica in mineral admixture mortars caused an increase in strength at early ages and it is very likely that these increases are due to the hydration kinetics differentiations.

Key words:

mineral additives, fly ash, nano-silica, nano-SiO₂, colloid silica