Characterization of silicon-manganese iron slag for employment in base and sub-base layers for highway

The impact generated by the waste from the steel industry has prompted a series of discussions about the most environmentally friendly forms of final destination, such as reuse of byproducts resulting from the process of metal alloy generation. This is even more relevant after the environmental disaster in the state of Minas Gerais, Brazil, in 2015, when a tailings dam broke, causing widespread destruction of towns and pollution of rivers. To mitigate these problems, this paper presents the results of ongoing studies for the characterization of silicon-manganese iron slag and its potential application in mixtures with soil for the construction of base and subbase layers of highway pavement. Some methods used are traditional, such as measurement of granulometry, bulk density, absorption and Los Angeles abrasion. Others have more recently been applied to characterize aggregates, like scanning electron microscopy (SEM) and aggregate image measurement (AIM). Complementarily, due to the vitreous appearance the slag, ductility results are reported, obtained according to degradation after Proctor compaction testing and determination of shock loss in a Treton apparatus. Finally, the results already obtained, along with those of studies with the same material for rail ballast and asphalt concrete, show that silicon-manganese iron slag presents geotechnical properties compatible with those established in the specifications for use in base and subbase layers of highways.