Enhancement mechanism of asphalt mixture skeleton structures due to morphological characteristics of steel slag

Uncertainty still exists about the enhancement mechanism of the skeleton structure brought about by the steel slag, and the relationship between skeleton structure of steel slag asphalt mixture and the mechanical properties is still ambiguous. This study quantified the skeleton structure of steel slag asphalt mixture and explored the enhancement mechanism of skeleton structure brought about by the steel slag. The relationship between skeleton parameters and mechanical properties of steel slag asphalt mixture was also established. The results show that recycling steel slag as aggregate improves the skeleton quality of mix. The slag particles are not susceptible to be oriented tending to the horizontal direction. The abundant angularity of steel slag increased the contact number while the rough texture and non-spherical shape of steel slag enhanced the contact length. This project provided new insight and a notable opportunity to advance the comprehension of the skeleton structure of asphalt mixture containing steel slag. •The skeleton structures of steel slag asphalt mixture were quantified.•The enhancement mechanism of skeleton structure brought about by the steel slag was explored.•The relationship between skeleton and properties of steel slag asphalt mixture was established.•The advancement of contact number originates from the richer angularity of steel slag.•The improvement of contact length results from the rougher texture and non-spherical shape.