Self-Healing Potential of Porous Asphalt Concrete Containing Different Aggregates and Metal Wastes Through Microwave Heating

Abstract

Asphalt is known as a self-healing material due to its temperature-related flow behavior. When damage occurs in asphalt concrete, bitumen can flow into cracks with heat and provide recovering by filling the cracks. Much of the current literature on self-healing pays particular attention to artificially heat asphalt concrete by several methods, including microwave heating. Although there is a growing body of literature that recognizes using steel fibers in microwave healing asphalt, there are no data on the use of aluminum fibers to improve microwave healing. This paper evaluates the microwave healing potential of asphalt concrete that contains metal wastes such as aluminum and steel shavings. Besides, the use of basalt and limestone aggregate (BA and LA) in asphalt concrete were evaluated. To achieve this, firstly, microwave absorption capabilities of BA and LA were determined. In the second step of the study, porous asphalt concrete specimens were prepared, and they were damaged by the indirect tensile (IDT) strength test at low temperatures. After that, damaged specimens were healed via microwave heating, and they were damaged again by the IDT strength test. In the end, the healing index of the specimens was determined as the proportion of healed specimen’s strength to the original. It has been found that BA is almost three times more microwave absorber material than LA, and asphalt specimens containing BA showed better healing performance. It has also been demonstrated for the first time that aluminum shavings might be a better option than steel shavings to accelerate microwave healing.