Effect of red mud filler on mechanical and buckling characteristics of coir fibre-reinforced polymer composite

Red mud produced as by-product in Bayer's process for alumina production is posing severe environmental challenge in its disposal. Present work describes using this environmental pollutant as filler in combination with coir fibre using polyester resin for composite production. Tensile properties, flexural properties, compressive properties, hardness and density of coir polymer composites with and without red mud filler were evaluated experimentally. Subsequently, buckling analysis of the prepared composite was also done experimentally and using finite element method at different grid size and for different number of elements to establish the grid independence of obtained results. It has been observed that compressive strength, hardness and density of the prepared composite improved with addition of red mud as filler. This may be attributed to metallic oxides present in chemical composition of red mud. Addition of the filler had a negative effect on tensile and buckling properties as the load cannot be transferred effectively from fibre to resin. Interestingly, it has been observed that composite plates with 20 % fibre gave optimum combination of various properties. The main aim of this work was to study the effect of red mud filler on the mechanical properties and buckling strength of the prepared composites leading to development of a novel low-cost, light-weight composite material using an environmental pollutant which can be used for lightweight structural application.