Avaliação da autocicatrização em concretos com diferentes composições: influência de materiais suplementares e aditivo cristalizante
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Data
2025-05-09
Autores
Santos, Érica Batista
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Universidade Federal do Espírito Santo
Resumo
Reinforced concrete structures are prone to cracks, which serve as entry points for aggressive agents such as chloride ions, which accelerate reinforcement corrosion and consequently reduce the structure's service life. Enabling cementitious matrices to heal soon after cracks appear saves on inspections and structural repairs. To this end, supplementary materials (silica fume, blast furnace slag, and fly ash) and chemical additives (crystallizing agents) are added to the cementitious matrix to promote crack self-healing. This study aims to evaluate the self-healing of cracks in different concretes. Five types of concrete were produced: a reference concrete without any additives (CPV ARI); a concrete with 10% of the cement mass replaced by silica fume; a concrete with 50% of the cement replaced by fly ash; a concrete with 75% of the cement replaced by blast furnace slag; and a concrete with the addition of a crystallizing additive (1% by cement mass). Crack opening occurred after 28 days of curing, with two crack width ranges considered: 0.1 to 0.2 mm and 0.3 to 0.4 mm. The analyses included self-healing evaluation using chloride migration tests, ultrasonic wave propagation to obtain the concrete moduli and self-healing rate, and qualitative image analysis. Regarding the results found, in general it can be said that all concretes healed partially or completely, with the concrete containing 75% blast furnace slag presenting greater resistance to chloride penetration and the concretes with 50% fly ash and crystallizing additive (1%) presenting better performance in the ultrasonic wave propagation test, obtaining the highest self-healing rates at 28 and 91 days, respectively.
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Autocicatrização , Migração de cloretos , Fissuras