Autocicatrização de concretos com aditivos cristalizantes e materiais cimentícios suplementares: análise da migração de cloretos e da evolução microestrutural
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Data
2025-10-30
Autores
Barreto, Leonnardo Postinghel
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Universidade Federal do Espírito Santo
Resumo
Reinforced concrete structures are prone to cracking, which facilitates the ingress of aggressive agents, especially chloride ions, thereby reducing durability. This study aimed to evaluate the self-healing phenomenon in concretes containing silica fume, blast furnace slag, fly ash, a crystalline admixture, and a reference concrete. To quantify chloride ion permeability, the electrical migration test according to ASTM C1202 (2022) was employed. Additionally, qualitative analyses were conducted through stereoscopic optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), in order to identify and characterize the healing products. The statistical analysis of the results allowed the classification of the specimens according to ASTM C1202. Concretes with slag and silica fume showed the lowest charge passed values, demonstrating better performance against chloride ion penetration. In contrast, the reference concrete and the crystalline admixture presented higher charge passed values. Microstructural characterization confirmed the presence of hydration products and precipitates associated with crack closure and reduced charge passed, particularly in concretes with slag and silica fume. EDS analyses revealed substantial differences in the products formed inside cracks after self-healing. The pozzolanic effect proved highly effective through the formation of secondary C–S–H, while CaCO₃ in calcite form was observed in all mixtures with different morphologies. Magnesium was also detected, mainly in concretes with higher levels of free calcium hydroxide
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Autocicatrização de concretos , ASTM C1202 , Self-healing in concretes