Strength and durability characteristic of alkali activated GGBS stabilized red mud as geo-material

Abstract

Red mud (bauxite residue) is generated during the Bayer's process of aluminium production in the ratio of one part aluminium to 0.8�1.5 part red mud and is considered as an industrial waste. The storage of unutilised red mud creates a geoenvironmental problem due to its highly alkaline nature (pH > 11) as it contaminates the groundwater as well as surface water. The present paper discusses the strength and durability properties of the stabilized red mud using alkali (Na 2 SiO 3 ) activated ground granulated blast furnace slag (GGBS) and its microstructural property for possible application as a geo-material. One of the major problems associated with the geo-materials is the strength loss and weathering due to the exposure to adverse environment. So, the emphasis has been given to the durability of the stabilized red mud by keeping in mind its various uses in geotechnical construction. The durability studies are performed by considering the effect of wet-dry cycles on compressive strength. In addition, the results of slake durability test and impact strength index are also discussed. The microstructural and chemical investigations are performed using scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively, to correlate with the strength and durability characteristics. The chemistry of leachate in terms of heavy toxic metals (Hg, As, Pb, and Cr) as identified by EPA is also studied and it was found that the stabilized red mud is non-toxic. � 2019 Elsevier Ltd