Rice husk ash as a potential supplementary cementitious material in concrete solution towards sustainable construction

With the increasing infrastructure and the need to maintain eco-friendly atmosphere, the role of concrete as a construction material is increasing day by day. Concrete being the second-largest consumed material after water requires alternate sustainable materials to be used especially those generated from waste. India stands at second place for rice production among various of the world, as it is one of the most important staple foods. Rice husk or hull is the outer shell of a rice grain which is parted from the grain during the process of milling. The disposal of this rice husk is causing environmental problem and hence its reuse is emphasised. Rice husk ash (RHA) which is obtained by burning the rice husk in between 600 and 700 degrees C for 2 h contains huge amount of non-crystalline silica dioxide of high specific surface area, high pozzolanic reactivity and hence can be utilised as a supplementary material to cement in the making of concrete. The present study based on the extensive review highlights the possibility for utilising the RHA as a conventional binder in concrete. Physical, chemical and mechanical properties of various concretes with RHA will also be reviewed. In a nutshell from the review of literature, it was also observed that the concrete manufactured using RHA has low workability in comparison to conventional concrete. The density of concrete containing RHA is less than that of conventional concrete and hence RHA can be used for wide range of applications. The mechanical properties like compressive strength, flexural strength and splitting tensile strength of concrete blended with RHA increases for smaller replacement (for up to 30%). Concrete with RHA shows better bond strength when compared to conventional mix and it also reduces chloride diffusion, efflorescence and increases resistance to sulphate and chemical attacks.