Utilizing Steelmaking By-Products for Pavement Deicing : A Sustainable Waste Management Approach in Circular Economy

A substantial amount of solid waste, including steel slag (SS) and iron slag (IS), is produced annually. Recycling and repurposing these slags in pavement design to enhance microwave deicing efficiency presents a promising solution and a better circular economy. To investigate this potential, the static magnetic and microwave absorption properties of SS, IS, and limestone were explored using a vibrating sample magnetometer (VSM) and vector network analyzer (VNA). Pavement samples with varying slag contents were then heated in a microwave oven to evaluate their deicing performance. The deformation resistance, strength, and water damage resistance of samples were next measured. A cost–benefit and material circularity index (MCI) analysis was also conducted to compare conventional pavements with slag-containing alternatives. Results indicate that both SS and IS exhibit soft magnetic properties suitable for microwave heating. SS demonstrated superior compatibility with microwave heating at a 2.45 GHz frequency, while the microwave absorption properties of IS were notably frequency-dependent. Pavements containing SS increased microwave deicing efficiency by up to 44.66% and 32.90% at initial temperatures of − 10 °C and − 20 °C, respectively. Similarly, IS-containing pavements achieved efficiency gains of 29.01% and 20.79% at the same temperatures. The economic analysis revealed that slag-containing pavements, particularly those with IS, offer significant cost advantages over conventional pavements. Meanwhile, SS-containing pavements can achieve better circularity. This study demonstrates that incorporating slags in pavement not only enhances microwave deicing efficiency but also reduces the demand for natural limestone, contributing to effective solid waste management and exemplifying circular economy principles.