Swelling Potential and Performance Level of Hot Mix Asphalt Containing Not-Hydrated Ladle Furnace Steel Slags as Filler

Abstract

Nowadays, the use of carbon-neutral materials is an urgent need because of energy consumption and CO2-emissions concerns. Thus, the use of ladle furnace steel slags (LFSs) is becoming common in asphalt pavement fields. One of the limitations on using LFSs is linked to swelling potential because of the changes in chemical structure due to the hydration of their components. In this study, two different asphalt binders, neat and 3.5 % styrene-butadiene-styrene modified, were mixed with limestone coarse aggregates and two fillers (limestone and LFSs) to analyze the swelling potential and the performance levels of hot mix asphalts containing not-hydrated LFSs as filler. The analysis was conducted performing the SuperPave indirect tensile test protocol at 10°C and by using a 3D-digital image correlation metadata model (3D-DICM) capable of computing the volumetric expansion of materials after four different periods of conditioning in water (24, 48, 168, and 336 h). The results showed no significant differences among the analyzed materials, highlighting that the volumetric expansion is mainly linked to the aggregates’ water absorption. On the other hand, conditioning time seems to affect the deformability of the mixtures, influencing performance level.