Mixing of Different Particle-Size Fractions of Fly Ash to Increase its Activity in Cement Composites

Abstract

Fly ash residue from coal burning process in power plants have been used as an active additive in concrete since middle of nineteenth century. Nowadays, we are trying to maximize its reactivity in cement composites by several methods. One of the methods is mechanical activation by mixing several size fractions to reach ideal particle size distribution. Ideal particle size distribution of fine components in cement composites helps to reach maximal compactness and thus increases strength and durability. In this paper we present results of compressive and tensile strength of cement-fly ash mortars with mixing 3 size fractions origins in 3 electrostatic precipitators from power plant Tušimice. Fly ashes from 1st precipitator, 2nd precipitator and 3rd precipitator were mixed with ration 10:4:1, 5:4:1 a 0:4:1.