Análise da adição de resíduos siderúrgicos em matrizes cimentícias para concreto massa

Abstract

During the steel production process, industrial waste is generated, including granulated blast furnace slag and balloon powder, generated in the pig iron production stage; and electric arc furnace dust, obtained in the production stage of the steelworks. In the northern region, the highlight in steel production is SINOBRAS - Siderúrgica Norte Brasil SA, located in the municipality of Marabá-PA, which also experiences the problem of waste disposal, and therefore has been supporting partnerships with educational institutions in the region for expansion of destination alternatives. Thus, this research aims to evaluate the influence of waste from the SINOBRAS industry, granulated blast furnace slag (GBFS), balloon powder (BP) and electric arc furnace dust (EAFD) in cementitious matrices, predicting applications in mass concrete for dams . The research methodology was carried out in two stages, the first being directed towards the study of waste, analyzing its physicochemical and mineralogical characteristics, the pozzolanicity potential according to ABNT NBR 12653:2015, and classification according to the type of solid waste according to ABNT NBR 10004:2004. The second stage of the methodology comprised the analysis of cement matrices composed of the residues, combined with GBFS (GBFS70+BP30; GBFS50+EAFD50), in order to increase the potential performance of the properties verified for mass concrete, with compressive strength tests being carried out, setting times, heat of hydration and alkali-aggregate reaction. It was concluded in the residue study stage that BP and EAFD did not present pozzolanic properties, indicating that they are not interesting for applications of cementitious materials. As for the classification, the GBFS and the BP were classified as class IIA waste - non-hazardous and non-inert, while the EAFD was classified as class I - hazardous. In the second stage of the study, the EAFD combined with the GBFS showed pozzolanicity and the BP, even after combination, remained non-pozzolanic. Evaluating the combined cementitious matrices, the (GBFS50+EAFD50) obtained satisfactory results in all properties, since it promoted a reduction of heat of hydration by 7% and, consequently, an increase in setting times (about 6 hours), and mitigation of expansion reactions, in aggregates gravel and sand by 49%. and 75% respectively. Therefore, the use of the matrix GBFS50+EAFD50, in the studied content, can be a technically viable alternative for applications in mass concrete for dams, being necessary, however, to advance in the research, aiming to produce the concrete traces composed by the matrix combined (GBFS50+EAFD50).