Crack-healing variability of asphalt mixtures with RAP and steel wool fibers by the action of external microwave heating

Abstract

Microwave heating of asphalt pavement containing steel wool fibers is an auspicious technology for asphalt pavement rehabilitation. These types of mixtures have the ability to self-heal their cracks when external microwave heating is applied. The assessment of crack-healing has mainly been conducted in mixtures prepared with virgin aggregate materials. This paper studies the variability of the crack-healing in asphalt mixtures prepared with reclaimed asphalt pavement (RAP) and steel wool fibers. The healing ratio was calculated using three-point bending strength of semi-circular asphalt specimens. The average of seven healing cycles applied on the asphalt specimens showed that the general effect of RAP content was an increase in the variability of the crack-healing of the mixtures. Low fibers contents of 1% and 2% reduced the variability of the crack-healing capabilities of asphalt mixtures. It was observed that the number of healing cycles reduce the variability of the healing capabilities of asphalt mixtures. Overall, it is concluded that small contents of fibers and RAP do not increase the variability in the crack-healing of this type of mixtures.