Fatigue characterization of asphalt mixes containing electric arc furnace (EAF) steel slag subjected to long term aging

In this paper fatigue behavior of asphalt mixes containing electric arc furnace (EAF) steel slag is evaluated in both aged and unaged conditions. Six sets of laboratory mixtures were prepared. Each set was treated replacing various portions of limestone coarse aggregates (⩾2.36 mm) with EAF steel slag. Four point bending beam fatigue testing was performed in controlled stress mode at various stress levels to characterize the fatigue behavior of the asphalt mixes. Various approaches, based on stiffness and dissipated energy were used to analyze the fatigue tests data which then used to develop fatigue models. Moreover, in order to evaluate long term performance of mixes containing EAF slag, the specimens were subjected to aging according to AASHTO PP2 standard testing method. The results showed that the inclusion of EAF in mixes improved fatigue life of samples considerably. For aged specimens, the fatigue life did not change appreciably. This was as a result of greater stiffness of mixes containing low percentages of EAF slag. This finding approved the hypothesis which was suggested that the greater the adhesion, the greater the mitigation of aging in asphalt mixes.