Estudo sobre a influência da adição de resíduo de minério de ferro da barragem de Fundão, Mariana-MG, como pigmento e nas propriedades do concreto de cimento Portland

Abstract

The extraction of iron ore in Brazil plays a fundamental role in economic and social development, contributing to the support of several families in much of Brazil. However, the mining industry is irresponsible with the management of its waste in order to reduce the impacts caused by the increasing accumulation of waste from this activity. In order to minimize the environmental, social and economic impacts caused by the mining activity, this work proposes the use of iron ore tailings as a pigment for the production of colored concretes. The waste used originates from the mining activity of the state of Minas Gerais, specifically in the tailings dam of Fundão, Mariana - MG. For this work, the residue was subjected to drying, dewatering and sieving, shortly after this treatment was called Waste of Iron Ore Processingm (RBMFt). They were made with water/cement ratio of 0.45 and 0.60, with additions of 0%, 5%, 10% and 15% of RBMFt. The influence of the additions of the residue on the mechanical strength of the concretes with the tests of tensile strength by diametrical compression and resistance to axial compression, its durability was verified by means of the tests of absorption of water by immersion and boiling and by the test of water absorption by capillarity, the color variation was analyzed based on the CIELAB color space. In relation to the coloration of the concretes, it was observed that the concretes with w/c = 0.45 and additions of 10 and 15%, presented greater color variation in relation to the reference. Regarding the mechanical strength, the additions of 10% of the RBMFt, in concretes with respect to w/c = 0.45 and 0.60, presented better results in relation to their references. By analyzing the durability of the concretes, it was observed that the additions of 10 and 15% in the concretes with w/c = 0.45 and 0.60 provide a lower absorption of water by immersion and by capillarity, which demonstrates that the additions can contribute to the useful life of concrete.