Rheological behavior of high performance concrete with mineral admixtures and their blending

Rice husk is a waste product that causes pollution and disposal problem. India is the second largest producer of rice in the world and effective use of rice husk ash in concrete is promising. Silica fume and fly ash are also waste products in some other processes and are excellent mineral admixtures of concrete. The effect of these admixtures on rheological behavior of high performance concrete have been investigated and presented in this paper. It has been observed that yield stress decreases as the replacement level of rice husk ash and fly ash increases. On the other hand, silica fume seems to be a better material for moderate plastic viscosity needed for the design of high performance concrete. For low yield stress and moderate plastic viscosity, blending of equal masses of silica fume and rice husk ash seems to be a suitable admixture at different replacement levels.