Crack healing performance of hot mix asphalt containing steel slag by microwaves heating

This study aims to analyze the applicability of steel slag in the asphalt mixtures for the self-healing purpose using microwave heating technique. Hot mix asphalt (HMA) mixtures were developed from four different levels of steel wool fibers (SWF) as a conductive additive and two types of aggregate were used: steel slag aggregate and conventional aggregate. Then, the thermal distribution, as well as the optimum healing time of test samples, were recorded by the infrared camera. 10 damage-healing cycles were applied in all mixtures to evaluate their healing performance under microwave heat. Test results suggested that adding two percent SWF by weight of asphalt mixture provides the best healing level for both types of aggregate mixtures. At this SWF level, the substitution of 30% normal coarse aggregate by steel slag is very promising due to its presence not only provides better healing results but also helps the whole mixture improve the load-displacement relationship with higher ductile behavior. Overall, the application of steel slag in HMA is a prominent solution which contributes toward the sustainable development.