Environmental impacts and mechanical properties of lightweight concrete containing bauxite residue (red mud)

Bauxite residue (Red mud) is one of the industrial caustic waste materials obtained from alumina production. Because of high annual production, it requires high costs and vast landfills to dispose it. In addition, due to high alkalinity, disposal of red mud (RM) may cause serious environmental problems. Considering use of concrete beside economic and environmental issues of cement production, replacing cement by industrial waste seems inevitable. In this study, RM has been used as high as 25% replacement of cement mass in order to study the performance of this waste material on lightweight concrete (LWC) in terms of their mechanical properties, global warming potential (GWP), cumulative energy demand (CED) and major criteria air pollutants (CO, NOx, Pb, SO2). For the quantification of overall environmental impacts of LWC production, a life-cycle assessment (LCA) approach has been conducted. The results indicated that RM can be used to produce LWC with convenient mechanical properties and densities of 1685-1789 (kg/m(3)). Moreover, the environmental impacts of LWC incorporating 25% of RM reduced in terms of CED, GWP, CO, NOx, Pb and SO2. Consequently, reusing RM waste which is otherwise disposed in landfills is an environmental-friendly alternative. (C) 2017 Elsevier Ltd. All rights reserved.