Autocicatrização de materiais cimentícios com aditivos cristalizantes

Abstract

The present work aims to evaluate the influence on the self-healing of cracks in structural concrete produced with Portland cement (CP V ARI – RS) using different crystallizing additives. After the preparation of the concrete, samples were tested for compressive strength at the ages of 3 and 14 days. The preloads were carried out in the laboratory and for each age of loading, three samples of each trait were broken up to the limit. From the mean failure value obtained, the percentage of load that would be applied to part of the concrete (75% of fcj) was determined. Before and after loading, the specimens remained in submerged curing in order to increase the self-healing. Control tests (axial compressive strength and water absorption by capillarity) were performed at the ages of 28 and 76 days. The results obtained showed that: (i) through the axial compressive strength test, it was found that the crystallizing additives increased the mechanical strength of the concrete; (ii) the use of crystallizing additives promoted a significant reduction in water absorption by capillarity at the age of 28 to 76 days; (iii) loading age did not significantly influence the self-healing of concrete. It was concluded that all the crystallizing additives analyzed showed the same tendency of reduction of water absorption by capillarity over time and increase of the compressive strength. In summary, it is concluded that the use of crystallizing additive contributed positively to the self-healing process of the investigated concretes, improving the properties evaluated. Keywords: self-healing, crystallizing additives, concrete, cracks.