Environmental risks of using waste steel slag aggregates in road applications

Steel is an inherently never-ending product, in term of recycling and reuse. The steelmaking process creates an industrial by-product termed as slag. Electric Arc Furnace Slag (EAFS) and Ladle Furnace Slag (LFS) are both... [ view full abstract ]

Steel is an inherently never-ending product, in term of recycling and reuse. The steelmaking process creates an industrial by-product termed as slag. Electric Arc Furnace Slag (EAFS) and Ladle Furnace Slag (LFS) are both produced at different stages of steelmaking process respectively in electric arc furnaces and refining ladle furnaces. As part of this research, an extensive suite of engineering and environmental tests was undertaken on EAFS and LFS aggregates to assess their potential usage as road construction materials. The engineering evaluation included particle size distribution, hydrometer, organic content, flakiness index, Atterberg limits, particle density, water absorption, pH, minimum and maximum dry densities with a vibrating table, modified compaction, California Bearing Ratio (CBR) and Los Angeles (LA) abrasion tests. Furthermore, a suite of environmental tests comprising total and leachable heavy metal tests were undertaken on both types of steel slag aggregates. From an environmental perspective, EAFS and LFS were found to pose no environmental risks for use as aggregates in roadwork applications. LFS was found to be suitable as a construction material for pavement bases/subbases and engineering fills. EAFS, with to its comparatively lower CBR value, was found to be suitable as a construction material for pavement subbases and engineering fills. The usage of EAFS and LFS in roadwork applications would bring about a practical end-of-life alternative for their sustainable reuse.