No abstract

Waste polymers are widely used in asphalt modification, especially, in order to reduce their detrimental effect on the environment. This study discusses the usability of waste expanded polystyrene (EPS) foam in asphalt modification. In this respect, the EPS foam, which produces waste in both production and use stages, was mixed with bitumen by weight at the ratios of 2%, 4%, 6%, and 8%, and dry modification method was employed. The penetration, ductility, softening point, flash point, and specific gravity values of virgin bitumen were compared with waste EPS foam modified bitumen. The comparison was made by both graphical and statistical methods. A strong correlation between the physical properties of modified asphalt and the ratio of EPS foam was observed. A drop was observed in penetration and ductility values. Besides, it was found by statistical analyses that 2% of the increase in the additive ratio is not sufficient to make a significant difference in the physical properties of bitumen, therefore, the increase should be at least 4%. Overall, it is concluded that EPS foam additive can be used in bitumen modification for hot regions where low penetration is required.

No 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.