LAUSR

Abstract Growing concern over global warming has highlighted the use of warm mix asphalt (WMA) mixtures throughout the asphalt industry. Although WMA offers numerous advantages, it suffers from the problem of low temperature cracking. One solution is the adoption of self-healing asphalt technology. Therefore, this research aims to evaluate the effects of scrap metal additives on the mechanical and self-healing properties of asphalt mixtures through microwave heating. Three types of scrap metal are used in this study, namely steel shavings, recycled tire steel fibers, and copper slag filler. This study evaluates the morphological properties of steel shavings and recycled tire steel fibers using Field Emission Scanning Electron Microscopy (FESEM). In addition, mechanical properties are evaluated by employing moisture susceptibility and deformation strength tests. The thermal properties of samples containing scrap metal and the control sample were monitored using a thermography camera. Finally, the self-healing properties of asphalt samples were assessed by employing microwave heating at three different self-healing times of 20, 30, and 40 s. The results show that when copper slag filler is added, mixtures containing recycled tire steel fibers and metal shavings exhibit a higher degree of resistance to moisture and rutting. In addition, the surface temperature distribution of the samples shows that the use of copper slag filler, recycled steel shavings, or recycled tire steel fibers simultaneously resulted in improved temperature distribution on the sample surface. Moreover, the self-healing results showed that fiber contents higher than 2% can be replaced with copper slag filler.