Induced heating-healing characterization of activated carbon modified asphalt concrete under microwave radiation

• Published in: Construction & building materials Vol. 178; pp. 254 - 271
• Main Authors: Karimi, Mohammad M., Jahanbakhsh, Hamid, Jahangiri, Behnam, Moghadas Nejad, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.07.2018; Elsevier B.V
• Subjects: Activated carbon; Analysis; Asphalt concrete; Asphalt concrete performance; Cyclic breaking-healing; Induced heating and healing; Mechanical properties; Microwave radiation; Thermal properties; Iran; United States; Induced heating and healing; Cyclic breaking-healing; Microwave radiation; Asphalt concrete performance; Activated carbon
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.05.012

The activated carbon, as a binder-based modifier, is added to the asphalt concrete to enhance electro-magnetic (e.g., microwave) radiation absorption. The supplied microwave power leads to heating the modified asphalt binder inside the asphalt concrete through the eddy current (i.e., electrical) and high speed rotation of the bipolar molecules (i.e., magnetic) mechanisms. Raising the internal temperature causes the asphalt binder to flow through the micro-cracks. The flowing asphalt binder wets the micro-cracks surfaces and partially heals the damages. [Display omitted] •Activated carbon (AC) is proposed as the modifier to increase the electro-magnetic sensitivity.•Induced heating and healing of the asphalt concrete were studied.•AC enhances the electro-magnetic absorption of asphalt concrete without degrading the performance.•AC promotes the induced healing index (HI) of the asphalt concrete.•The effects of the testing mode, crack length, temperature and damage level on HI were investigated. This research investigates the crack healing ability of activated carbon (AC) modified asphalt concrete through microwave radiation. As a binder-based conductive additive, AC is expected to increase the electro-magnetic radiation absorption of asphalt binder. To verify this issue, neat and modified binders with different contents of AC were exposed to microwave radiation. It was found that the temperature of AC modified binder increased considerably after microwave heating compared to that of the neat binder. This observation can be regarded as a driving force to use AC in asphalt for the healing purposes. Moreover, statistical analysis of testing results showed that the AC modification did not have any detrimental effect on the asphalt performance. For further evaluation of the healing ability of AC modified asphalt, cycles of breaking and healing were applied to a number of semicircular bending (SCB) and indirect tensile (IDT) testing samples. Notch length, damage level (number of breaking-healing cycle), and aggregate source were found to have significant effects on the induced healing efficiency. The obtained results confirmed that AC is a potentially viable and robust binder-based conductive component for induced heating and healing of asphalt concrete.