Estimating service life of reinforced concrete structures with binders containing silica fume and metakaolin under chloride environment: durability indicators and probabilistic assessment

Pozzolanic additions, especially high reactive pozzolans, such as silica fume and metakaolin, currently stand out as the main alternatives for increasing the mechanical strength and resistance to the penetration of deleterious agents in concrete. Thus, the use of these materials will result in a longer service life of reinforced concrete structures exposed to aggressive environments. In this paper, the influence of silica fume and metakaolin on aspects related to the durability and service life of concretes subject to chloride penetration is evaluated. Through the evaluation of durability indicators, a performance-based approach is used in the analysis of the durability potential of the produced concrete. In order to cover the variability that can be assumed by the model parameters involved in the process of chloride penetration into concrete, a probabilistic assessment is performed using Monte Carlo Simulation with Importance Sampling. These calculations indicate that the use of silica fume and metakaolin generates significant improvements in the durability-related properties of concrete. When comparing mineral additions at equal levels, the most satisfactory results were obtained when using silica fume. Based on the obtained results, the importance of a performance-based approach is discussed and verified instead of the prescriptive approach. The results indicate that concretes that follow the same prescriptive parameters may present different behaviors when evaluated from the perspective of durability.