Estudo do uso de escória alto-forno no efeito autocicatrizante em concretos

Abstract

Concrete is the most used material in the construction industry, and can be used in the most diverse structures, such as bridges, highways, buildings, among others. However, to maintain the useful life and safety of these structures, it is necessary to carry out periodic maintenance, which can present a very high cost, which may be higher than a new construction. A strategy that has been studied in order to reduce the interval for these maintenances is self-healing concrete, which aims to close cracks right after they are opened, preventing the creation of large cracks and the entry of aggressive agents. In this work, the autogenous self-healing method was used from the partial replacement of CP V ARI cement by blast furnace slag in proportions of 25% and 50%. Different water/cement ratios ranging between 0.30, 0.40 and 0.50 were also evaluated. The cylindrical specimens were pre-cracked after 7 days, applying compression forces corresponding to 90% of the breaking load. In addition, they underwent compressive strength, capillary water absorption and optical microscopy tests at 28 and 63 days. The samples with the lowest water/cement ratio showed the best results in relation to compressive strength. In addition, the samples without cement replacement by slag showed higher values of compressive strength when compared to the others. Regarding the capillary water absorption tests, the absorption was greater at 63 days when compared to 28 days. In the optical microscopy test, it was possible to observe the beginning of the self-healing of the cracks more evident in samples with a water/cement ratio of 0.30. However, all analyzed samples showed evidence of the beginning of the healing process in the scanning electron microscopy analysis. [resumo fornecido pelo autor]