Use of waste rock and iron ore tailings in road pavement infrastructure

Abstract

The increase in the generation of waste from mining activities has motivated reflections on sustainability in the face of the serious environmental and social problems caused by the disposal of such products in the environment. Currently, the culture of tailings disposal and waste rock from iron mining is based on the construction of tailings dams and storage in waste piles. These procedures are totally contrary to sustainable development on the part of mining enterprises, as they demand large areas of the environment for their existence, in addition to having no purpose and putting the lives of populations and biomes neighboring the mines at risk. At the same time, Brazil is still going through another problem, which consists of improving the current situation of the highways, in terms of quality and quantity of paved roads. This fact seriously compromises the country's internal economic development, since highways are the main means of cargo transport and represent great importance for investments in the industry sector in general. Therefore, the present work aimed to propose an alternative destination for iron mining waste through its use in layers of road pavements. The methodology was based on the physical and mechanical analysis of mixtures containing such residues in compaction, CBR and expansion tests, as well as the subsequent comparison of the results with the standards in force in the country, imposed by the National Department of Transport Infrastructure (DNIT). The results obtained were very satisfactory, reaching high CBR indices and expansions within the required limits.