Optimum Proportions of Mineral Admixtures for Workability and Strength of High Strength Concrete
Concrete, most widely used construction material is found to be largely dependent upon the behaviour of its constituent phases such as aggregates, cement mortar and aggregate�paste interface. Moreover, a stronger and durable concrete could be achieved by modifying the behavior of cement mortar. Therefore, several investigations have been carried out to improve the behaviour of cement mortar and paste (A. M. Neville). Pozzolanic materials have been added in cement paste and mortar to enhance its mechanical and durability characteristics along with densification of microstructure. Previous investigations demonstrated that the incorporation of fly ash brought significant changes in the behaviour of cement paste and mortar along with reduction of consumption of cement quantity. In addition to fly ash, silica fume was found to be quite efficient in improving cement paste and mortar characteristics at early days owing to increased rate of cement hydration at early hours. Currently, new materials of nano-scale size have been invented with highly improved characteristics owing to the rapid progress in Nanotechnology. The nano-materials were found to be quite efficient in modification of the properties of concrete in nano-metric scale. Several investigations have been carried out to study the influence of NS on the strength of cement mortars. The outcomes of this study may indicate optimum Compressive Strength can be achieved when the factors cement content, water to powder ratio, fly ash, silica fume and Nano-silica and the dosage of super plasticiser. In sustainable development which is today�s coin word, it is required to save the natural resources for future generations. The aim of our project is to study the improvement in the mechanical properties of high strength concrete mix M-60 grade, with a partial replacement of cement with Nano Silica, silica fume and fly ash using Pozzolonic Reactivity Index to make concrete more green.
Keywords - Fly ash, silica fume, Nano Silica, Compressive strength, Pozzolonic Reactivity Index.