Probabilistic analysis of the useful life of reinforced concrete slabs subjected to carbonation corrosion by Monte Carlo simulation

ABSTRACT

In this work we propose a coupled mechanical-probabilistic analysis of the useful life of reinforced concrete slabs under uniform corrosion due to CO₂ diffusion. The alternative approach considers analytical formulations for the mechanical behavior of concrete coupled to a model based on Artificial Intelligence and the Monte Carlo simulation. The initiation and propagation periods are determined by the probability of occurrence of the limit states of depassivation and flexural strength, respectively. The results show that depending on the quality control of concrete, concrete cover and exposure environment, the useful life can be drastically reduced. In many cases the structural reliability and durability are lower than the specified in design. Thus, it is recommended to use Brazilian Portland cements type CP V, CP II F, CP II E and CP II Z (or equivalents) for the production of concrete structures in environments with high CO₂ concentration. Furthermore, we show that that purely deterministic approaches are not able to adequately assess the useful life of concrete structures under corrosion. One must consider the randomly distribution of the parameters associates to the deterioration process to accurately represent the corrosion process and its consequences.

Keywords
reinforced concrete slab; concrete deterioration; corrosion; Monte Carlo simulation