Durabilidade de concretos com incorporação de escória de Ferroníquel como material cimentício suplementar : migração de íons cloreto, carbonatação e análise microestrutural
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Data
2026-02-26
Autores
Quinquim, Thiago Almeida
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Universidade Federal do Espírito Santo
Resumo
Partial replacement of Portland cement with supplementary cementitious materials (SCMs) is a consistent strategy to enhance the sustainability of the construction sector by reducing the clinker factor and its environmental impacts, especially when these materials are regionally available. This study investigated the technical feasibility of incorporating ground ferronickel slag (FNS) as an SCM in concrete, evaluating mechanical performance, durability indicators, and microstructural evidence. The mixtures were produced with a constant water-to-binder ratio and different replacement levels (including a reference mixture and a composition with inert limestone filler). Performance was assessed through compressive strength, chloride transport tests (passed charge and migration coefficient), electrical resistivity, volume of permeable voids, and accelerated carbonation. The interpretation of the results was supported at the microstructural level by synchrotron X-ray diffraction with quantitative refinement and thermogravimetric analysis, enabling relationships between composition/mineralogy and hydration evolution to be established. FNS, characterized by a low Ca/Si ratio and a considerable siliceous amorphous fraction, exhibited predominantly late pozzolanic reactivity, consuming Ca(OH)2 and forming additional C–S–H, which promoted matrix densification. At later ages, a consistent reduction in ionic transport and volume of permeable voids were observed, accompanied by increased electrical resistivity, indicating greater resistance to chloride ingress. However, high replacement levels increased vulnerability to carbonation, mainly at early ages, attributed to clinker dilution and reduced alkaline reserve, although late age densification partially mitigated this effect. Overall, replacement levels around 30% provided the best balance between mechanical performance, durability gains, and carbonation resistance.
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Concreto , Escória de Ferroníquel , Durabilidade , Concrete , Ferronickel slag , Durability