Study of Influence of Rice-Husk Fly Ash on Compressive Strength of Concrete at Different Ages

The possibility of rice-husk ash utilization in the production of structural concrete is very important for both Brazil - one of the major rice producers worldwide - and Uruguay, where rice is a major crop. Rice-husk ash is mainly used as fuel in rice paddy milling processes. The use of this fuel generates a great volume of ash that causes air, soil and water springs pollution and contamination; therefore the utilization of such ash has aroused the interest of researchers in both countries. For this reason, this paper presents a theoretical and an experimental study on the effects of the substitution of different percentages of portland cement by rice-husk ash on the compressive strength of concrete at different ages. Results are compared with those of portland cement without rice-husk ash. For a better understanding of mechanical performance, research is done into the microstructural study which was undertaken using Scanning Electron Microscopy and X-ray Diffraction Analysis. It was concluded that the rice-husk ash used in this study was burnt at too high a temperature to produce a highly active pozzolan.