The use of electric arc furnace steel slags in bituminous mixtures: a laboratory evaluation

The possibility to reuse marginal materials deriving from the industrial activities, in the construction of road infrastructures, as total or partial substitution of the natural aggregates, happily conjugates demands for economic convenience and environmental sustainability. This paper presents the results of a laboratory study, conducted at the Experimental Road Laboratory of the University of Padova, aimed to verify the suitability of a particular typology of slag to be recycled in the lithic skeleton of high-performance bituminous mixes (porous asphalt, high modulus mixes, stone mastic asphalt) for road and airport flexible pavements. The mix-design has been based on the use of the customary Marshall methodology as well as a gyratory compactor, which allowed useful information to be acquired about the shear strength and the density of mixes during compaction. The mechanical behaviour was evaluated by means of the Marshall test, indirect tensile strength test, dynamic modulus, and dynamic creep test. This study forms a part of a wider theoretical – experimental research being done at the University of Padova in order to improve the knowledge of the characteristics of succedaneum materials and check up their possible applications in the road and airport construction.