Author : M. P. Deshmukh, D.D. Sarode and Avijit Chaube

Consumption of concrete, mortar and other cement based composites is over 20 billion tonnes per annum, globally. Natural sand/crushed fine aggregates(CFA) are important ingredients of concrete. Aggregates contributes 60% to 80% of the total concrete volume. The available sources of natural sand are getting exhausted because of excessive sand mining. Bulk utilisation of crushed fine aggregates is causing a great ecological imbalance of natural system. Hence there is an urgent need to explore a substitute material for fine aggregates in concrete. An inventory of about 3 billion tonnes of red mud (bauxite residue) is awaiting in stock-pilling yards for its utilization and 120 million tonnes of red mud is added every year in it. This high alkaline red mud generated during the production of allumina is posing a serious threat to the environment. An attempt is made here to substitute fine aggregate in concrete with raw red mud. For this, an experimental study is carried out by casting concrete cube moulds for 0%(control mix), 5%, 10%, 15%, 20% replacement of crushed fine aggregates with red mud. Concrete cubes are then tested for compressive and tensile strength. Rapid chloride permeability tests(RCPT) are also carried out to determine the effect of addition of red mud on durability of concrete. It is observed that addition of red mud imparts better resistance to chloride penetration. Thus, Conservation of crushed fine aggregates is achieved and a better durable and economical concrete can be produced for sustainable developments and clean technology.

Keywords: Bauxite residue, Aggregate, Red mud, Permeability, Compressive, Tensile, Chloride

Article published in International Journal of Current Engineering and Technology, Vol.4, No.6 (Dec-2014)