Geotechnical properties of ladle furnace slag in Roadwork applications

Ladle Furnace Slag (LFS) is an industrial waste from steelmaking process, generated during the final stage in ladle refining furnace. LFS samples were sourced from a steelmaking company in Victoria, Australia. This paper reports on the results of a geotechnical and chemical evaluation on LFS to assess the viability of using this byproduct in roadwork constructions. A comprehensive suits of engineering tests was undertaken comprising moisture content, specific gravity, particle size analysis, hydrometer, organic content, flakiness index, Los Angeles (LA) abrasion, hydraulic conductivity, modified compaction, pH, Unconfined Compression Strength (UCS) and California Bearing Ratio (CBR). In addition, the chemical composition of LFS sample was assessed using X-ray Fluorescence analysis (XRF). The engineering properties of LFS were then compared with typical quarry materials. The chemical composition results indicate that LFS contains high amount of calcium. Thus, the effect of 0, 7 and 28 days of curing on the strength of unbound LFS was investigated using UCS test. The specimens with 7 and 28days curing had higher UCS value than uncured samples attributed to high lime content and hydration process. From an engineering perspective, LFS was found to be suitable material to substitute typical quarry material in roadwork applications. The reuse of LFS in roadwork construction will significantly reduce the demand of natural quarry aggregates and will possibly divert huge amount of these waste from landfills and stockpiles. Possible applications of unbound LFS in road pavement are also discussed.