Performance evaluation of stabilised soil–slag mixes as highway construction material

This paper presents an investigation on effective utilisation of steel slag, a by-product from the steel industry, as construction material in highway pavement layers so that the industrial wastes can be used and disposed properly with reduction in environmental impact as well as the demand for natural construction materials can be minimised. Steel slag was mechanically stabilised with locally available Powai soil (silty soil with intermediate plasticity) of ranges from 20 to 70% by weight, considering the utilisation in embankments and road pavement layer constructions. The mix as 30% slag and 70% soil provided the optimum strength based on the California bearing ratio (CBR) value and unconfined compressive strength (UCS).The optimum slag–soil mix was chemically stabilised using ordinary Portland cement and nanomaterial (amorphous nanosilica) in different percentage ranges, 4–10% for only cement, 2–6% for only nanomaterial, and for the mixture of cement with nanomaterial, it was always 4% cement with varying nano-percentages from 2 to 6%. From the experimental analyses, it was observed that cement-stabilised optimum slag–soil mixes and cement with nanosilica-stabilised mixes satisfied the material specifications for the construction of pavement layers. It was also observed that steel slag–soil mixes acquired good strength, drainage and plasticity characteristics to act as a potential material for highway embankment construction.