Volume 62, Issue 342, September - December 2026

Comparative evaluation of (external oven and microwave induction) heating influence on healing mode and flow number (FN) of asphalt concrete (AC)

Saad Issa Sarsam^♦

Professor, Sarsam and Associates Consult Bureau (SACB), Baghdad, Iraq

^♦Corresponding author
Professor, Sarsam and Associates Consult Bureau (SACB), Baghdad, Iraq

ABSTRACT

Asphalt cement is a viscoelastic material and has self-healing abilities due to its viscous part. The interaction between fatigue and self-healing influences the fatigue life of asphalt concrete (AC). An attempt has been made in this work to evaluate and compare the influence of external oven and microwave induction heating on the mode of healing, permanent deformation (PD), and flow number (FN) of AC, while two sets of AC Marshall specimens were prepared with optimum binder requirement; the first set is denoted as the control while the second set is prepared with 5 % of iron slag. Specimens were subjected to fatigue under dynamic indirect tensile stress (DITS) until the stiffness declined to 50 % of its original value. Specimens were subjected to healing using two heating modes, (external oven and microwave induction) heating, then tested for fatigue using DITS. The variation in PD and FN among the healing modes between the control and the iron slag-treated specimens are analyzed and modeled. It was observed that implementation of iron slag has increased the FN by (four and nine) folds, and declined the PD by (37.5, and 50) % after practicing the healing with (microwave induction and external oven) heating respectively. External oven heating exhibited a lower PD healing index for control and iron slag-treated AC mixtures. However, implementation of 5 % iron slag exhibited lower healing index in general as compared with the control AC mixture. The obtained power regression mathematical models with high coefficients of determination can be implemented for fast and preliminary prediction of the expected PD within the limitations of the investigated material ranges and testing conditions when practicing the healing process.

Keywords: Healing; Asphalt Concrete; Deformation; Induction Heating; slag; external heating; Flow number, Microwave

Discovery, 2026, 62, e33d3339

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Published: 07 November 2026