The development of asphalt mixtures with improved electrical and thermal properties is crucial in terms of producing suitable mixtures for the induction heating without losing their durability. The main scope of this research is to evaluate experimentally the impact of filler-sized electrically conductive additives on the induction heating efficiency and the rheological performance of asphalt mixtures. Within this framework, an experimental assessment protocol of structural and non-structural important parameters of induction heated asphalt mastics – asphalt mixtures without stone aggregates and sand – was developed. It was observed that by adding iron powder as filler-sized conductive additive to asphalt mastics the electrical and thermal properties improve. Moreover, the rheological investigations of different conductive asphalt mastics show the importance of adding iron powder after replacing the amount of mineral filler in order to maintain the workability of mastics. The micro-morphological observation of asphalt mastics using scanning electron microscopy illustrates the impact of filler-size particles – minerals and conductive additives – on the skeleton of asphalt mastics.

The research reported in this paper focuses on utilization of advanced finite-element analyses (COMSOL) for the design and assessment of the induction heating capacity of asphalt mortar by adding electrically conductive additives (e.g., steel fibers), and to understand the factors that influence the mechanisms of induction heating in asphalt mixtures. In order to determine numerically the effective electrical and thermal properties of the conductive asphalt mortar with different volumes of steel fibers, 3D finite element meshes were generated by using X-ray images and utilized for calibration of the model parameters to perform a more realistic simulation of the asphalt mixture induction healing. The findings of this research are part of a study to provide an optimization method for the development of the necessary tools and equipment that will enable the implementation of induction technology for healing of asphalt concrete mixtures.

This paper studied the induction heating and healing capacity of asphalt mortar by adding electrically conductive additives (e.g. iron powder and steel fibers), and examined the influence of different combinations of them on the mechanical response of asphalt mortars. Induction heating technique is this innovative asphalt pavement maintenance method that is applied to the conductive asphalt concrete mixtures in order to prevent the formation of macro-cracks by increasing locally the temperature of asphalt mixtures. It was found that increasing steel fiber content within the asphalt mortar the tensile strength and the fatigue life increased respectively. It was also proved that the conductive asphalt mortars with iron powder appeared improved mechanical response when steel fibers were added. Furthermore, it was observed that asphalt mortars containing a combination of additives – steel fibers and iron powder - demonstrate a better induction heating efficiency than mortars including only steel fibers. Finally, the induction healing capacity of conductive asphalt mortars is determined.