Abstract EN:

Atmospheric carbonation is one of the most significant degradation factors for the durability of reinforced concrete structures. Carbonation relates to the diffusion of CO2 in the atmosphere through the concrete pores and to the dissolution of the hydrates, especially the portlandite, which supplies the reserve of concrete basicity. When portlandite is totally consumed, the pH value decreases to a value less than 9. It corresponds to the conditions allowing the corrosion of the reinforced bars which are protected only under a high pH level. The aim of this work is to carry out a probabilistic physico-chemical modelling of carbonation, taking into account the industrial requirements and being easy to utilize in a probabilistic design of the concrete cover. A wide experimental campaign was conducted in order to propose a practical model of carbonation for its efficient usage in the industry of precast concrete. From the cement nature, the concrete composition, the curing and thermal treatment characteristics, and one carbonation test (or at least the compressive strength), the model can determine the carbonated thickness for different pressures of CO2. Further, it allows the reliability index with respect to the initiation of corrosion to be estimated thanks to a link with a probabilistic algorithm. Following the scheme of checking the reliability level as recommended by the European regulation Eurocodes for structural design, the benefit of a probabilistic approach in the durability design of a concrete structure has been then emphasized.