ABSTRACT
Mining in Brazil plays a very important role in economic and social development, and it contributes directly to a better quality of life for people. However, mining activities, although performed in a responsible and sustainable manner, can cause harmful damages to the environment. In this paper, different mixtures of iron ore tailings with Brazilian tropical soil were evaluated in order to obtain a significant increase in the compaction test and California Bearing Ratio (CBR) results. The materials studied correspond to iron ore tailings and a Brazilian tropical soil, both from the Northeast region of Brazil. For the Compaction tests, three different compaction energies were used: normal, intermediate and modified energy. Thus, the values of optimal moisture content and dry density obtained ranged from 8.07% to 11.53%, and 2.11 g/cm3 to 2.58 g/cm3, respectively. It was verified that in all the compaction tests the optimal moisture content decreased with the increase of the dry bulk and compaction energy. Regarding the CBR tests, it was found that the mixture can be used up to the sub-base layer of pavements, since, according to Brazilian standards established by the National Department of Infrastructure and Transport (DNIT), materials with a CBR greater than or equal to 60.0% are required for the base layer in pavements. Therefore, the use of iron ore tailing as a constituent material in the sub-base layers in pavements offers a significant contribution in the improvement of the structural behavior of tropical soils, as well as a better environmental use of the iron ore tailings.
