Using Modified Bauxite Refinery Residue Waste in Concrete: Where are we at?

Abstract

Some 70 million tonnes of bauxite refinery residue (BRR) are generated globally each year, which poses a significant problem for the alumina industry because of high pH, alkalinity and dispersive nature. Hence, safe disposal and/or material reuse is critical from an environmental sustainability point of view. However, red mud may be modified using Ca and Mg brines and the modified bauxite refinery residue (MBRR) may be used as a replacement for sand in concrete which has the potential to use significant quantities of the waste material. Current studies have found that adding MBRR as a sand filler replacement did not affect the compressive strength, resulted in higher early flexural strength, improved resistance to carbonation and chloride ingress, improved the salt scaling resistance and improved the acid resistance of the concrete at 10% MBRR replacement. This paper reflects on the work already undertaken that investigate the effects of using MBRR as sand replacement in concrete. Manufacturing aspects such as, curing, physical properties and durability are discussed. Potential applications for MBRR use in concretes are also discussed with particular consideration of their use in aggressive environments.