Comportamento Elétrico De Compósitos Cimentícios Produzidos Com Resíduos Siderúrgicos

Abstract

The demand for safer structures has driven the development of self-sensing cement-based composites, capable of integrating structural and monitoring functions through intrinsic electrical properties. Traditionally, this functionalization is obtained by incorporating conductive carbon-based materials. However, the high cost of these materials and the limitations associated with their large-scale application motivate the search for more accessible alternatives. In this context, industrial waste with a composition rich in metallic oxides, such as

steelmaking waste, presents the potential to confer functional electrical capacity to cement- based composites, while simultaneously contributing to the mitigation of environmental

impacts associated with its disposal. Thus, this study carried out an investigation into the use of basic oxygen furnace (BOF) steel slag and scrap from the desulfurization process in the Kambara Reactor (KR) as a full replacement for natural fine aggregate. The physical, mechanical, and electrical behavior of mortars produced with this waste was evaluated, using a conventional mortar with natural sand as a reference. Additionally, a numerical modeling of the electrical test was developed and validated from experimental data, capable of reproducing both the magnitude and the temporal evolution of the electrical current. The results indicated that the mortar with BOF slag presented physical and mechanical performance similar to the reference mortar, whereas the mortar with KR scrap exhibited a higher void ratio and lower mechanical strength, a behavior associated with lower particle packing efficiency. Regarding the electrical properties, all mortars showed an increase in resistivity over the curing time. Nevertheless, the mortar with KR scrap presented systematically lower electrical resistivity values, resulting in higher conductivity compared to the reference and BOF mortars. The predictive analyses carried out through modeling indicated the maintenance of the trends observed experimentally, with a progressive reduction in electrical conductivity at later ages. Overall, the results demonstrate that steelmaking waste, especially KR scrap, can act as sustainable substitutes for natural aggregate. Furthermore, these wastes have the potential to act as functional constituents in the electrical behavior of cement-based composites, expanding their use in multifunctional materials for structural health monitoring