Análise do potencial da sílica ativa como adição para concretos de alto desempenho submetidos a meios agressivos

Abstract

This study compares high-performance concretes with and without the addition of silica fume. High-performance concretes are capable of achieving high strengths, greater than 60MPa, and also high durability. Silica fume is widely used in the production of concrete to improve properties such as mechanical strength and durability. Concretes were produced with the addition of 6%, 10% and 14% of silica fume. The results show that silica fume was able to increase the compressive strength by up to 10.36%, the elastic modulus by 9.48% and the tensile strength by diametral compression by 32.85%. Furthermore, we observed a reduction in water absorption by up to 25.79% and capillary absorption by up to 42.91%, proving the increase in the impermeability of the concrete, promoting greater durability. Concrete with silica fume also demonstrated greater resistance to aggressive environments, as the concretes were submerged in a sulfuric acid solution (2.5% H2SO4 solution) for seven days. After this period, their mechanical and physical characteristics were evaluated, with concrete with silica fume showing greater resistance in aggressive environments. These results suggest that silica fume can extend the useful life of concrete structures, reducing the need for maintenance and meeting the durability requirements of standard NBR 6118:2023. It is worth mentioning that the use of silica fume provides significant environmental gains, since cement production is much more aggressive to the environment, when compared to the production of silica fume.