Investigação ambiental e financeira do uso de agregado siderúrgico como lastro em pavimentos ferroviários

Abstract

Steel slag aggregate, a byproduct generated on a large-scale during steel production, is often stored in open yards, leading to environmental impacts and posing risks to human health. At the same time, the railway sector consumes thousands of tons of crushed natural rock as track ballast, the extraction of which also results in socioenvironmental impacts. Given global concerns about climate change and resource scarcity, the reuse of processed steel slag as railway ballast emerges as a promising alternative within the circular economy framework. This research aims to assess the environmental and financial feasibility of replacing traditional crushed rock ballast with steel slag. To achieve this, a Life Cycle Assessment (LCA) methodology was applied to a case study involving a railway operator and a steel plant located in the Southeast region of Brazil. The LCA followed a “cradle-to-grave” system boundary, meaning that the analysis includes all stages from resource extraction to end of life. The impact category considered was global warming potential (GWP), measured in emissions of kgCO2 equivalent, considering 1 km of railway as the functional unit. Additionally, were analyzed life cycle costs and the perceptions of railway sector professionals, collected through interviews. The results indicate that steel slag ballast has a global warming potential of −2.45E+05 kgCO2eq (i.e., it captures carbon), compared to 1.30E+04 kgCO₂eq for traditional ballast, highlighting its superior environmental performance. In the preliminary financial assessment, the life cycle cost for 1 km of railway using steel slag ballast was found to be 31.9% lower than that of traditional ballast, also demonstrating its economic viability. Therefore, the results of this study demonstrate that the comparative approach fulfilled its purpose, confirming the potential of steel slag aggregate as a sustainable solution for railway infrastructure, both environmentally and financially.