Microwave Healing Performance of Asphalt Mixture Containing Electric Arc Furnace (EAF) Slag and Graphene Nanoplatelets (GNPs)

Abstract

Pavement preventive maintenance is an important tool for extending the service life of the road pavements. Microwave heating seems to be a promising technology for this application, as bituminous materials have the potential to self-repair above a certain temperature. As ordinary asphalt mixture has low microwave absorbing properties, some additives should be used to improve the heating efficiency. In this paper, the effect of adding Electric Arc Furnace (EAF) slag and Graphene Nanoplatelets (GNPs) on the microwave heating and healing efficiency of asphalt mixtures was evaluated. Microwave heating efficiency was assessed by heating the specimens using several heating times. In addition, the electrical resistivity of the mixtures was measured to understand its possible relationship with the microwave heating process. Furthermore, the healing rates of the asphalt mixtures were assessed by repeated Indirect Tensile Strength (ITS) tests. The results obtained indicate that the additions of graphene and EAF slag can allow important savings, up to 50%, on the energy required to perform a good healing process.

Self-Healing Analysis of Half-Warm Asphalt Mixes Containing Electric Arc Furnace (EAF) Slag and Reclaimed Asphalt Pavement (RAP) Using a Novel Thermomechanical Healing Treatment

“…The solid blue healing curve represents the 0% EAF slag; the orange healing curve shows the recovery ratios belonging to 4% EAF slag, while the red curve presents the recovery rates for the 8% EAF slag. Indeed, these healing rate curves are a parameter of the healing efficiency of the energy consumed from the microwave heating process [32]. In particular, in Figure 12a, the slope of the healing curve of the 100% RAP mixture made with siliceous recycled aggregates remained at the same level of healing, regardless of the microwave heating temperature selected.…”

“…The cohesive and adhesive bonding interactions of asphalt-aggregate systems are strongly influenced by the Lifshitz-van der Waals interactions, and the acid-base interaction components [14]. Some examples of self-healing asphalt pavement technologies commonly mentioned in the literature review that possess the potential to reverse the fracture failure process and restore the loss in the mechanical performance properties (e.g., stiffness and strength) and functionality suffered by the asphalt pavements during their service life include (but are not limited to these solutions): (1) Encapsulated chemical products containing rejuvenator oil agents to repair broken bonds due to the accumulated micro-crack damage caused by the fatigue cracking process [15][16][17]; (2) magnetic induction heating technique in combination with conductive materials (e.g., steel wool, steel fibers, metal particles, carbon black, and graphite) to speed up the asphalt healing process [18][19][20][21][22][23]; (3) infrared heating technique [24][25][26]; (4) microwave radiation heating energy in combination with ferrous particle aggregates (EAF slag) in order to accelerate the heating and healing capability of the asphalt mixtures [27][28][29][30]; (5) the addition of Nanomaterials into the asphalt mixture design, such as carbon nanotubes (CNTs), carbon black nanoparticles (CBNPs), and graphene nanoplatelets (GNPs); the GNPs nanoparticles especially improve the resistance to permanent deformation, moisture damage, skid resistance [31], flexural strength at low temperatures, and increase the cohesion recovery ratios of the mixtures [32]; and (6) industrial microwave heating applications through a mobile microwave power unit for pavement maintenance works [33,34], with emphasis being placed on recycling techniques for surface layers [35].…”

“…Whereas, for steel wool fibers, they tend to cluster in balls and increase the air voids content, causing a substantial decrease in the mixture's mechanical response [42]. As for the GNPs nanoproduct, some authors reported that the nanoparticles tend to present some difficulties in achieving a homogeneous dispersion of GNPs in the asphalt binder as well as some issues related to high production and acquisition costs [32].…”

Special Issue on Nano-Modified Asphalt Binders and Mixtures to Enhance Pavement Performance

“…Another exciting application was brought by the paper [8] with the study of the effect of adding Electric Arc Furnace (EAF) slag and Graphene Nanoplatelets (GNPs) on the microwave heating and healing efficiency of asphalt mixtures. The results obtained indicate that the additions of graphene and EAF slag can allow significant savings, up to 50%, on the energy required to perform a proper healing process by microwave technology, which in any case is a technology still in development.…”

A Fast and Accurate Method for Computing the Microwave Heating of Moving Objects

“…Microwave heating has been widely used in many fields in the past few decades, including food processing, chemical engineering, medical health, and even graphene production [1][2][3][4]. Compared with traditional heating methods, it has numerous advantages like selective energy absorption, high-speed startup, high energy efficiency, and volumetric heating [5][6][7].…”