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Mai-Nhu J.,Studies and Research Center for the Precast Industries | Sellier A.,CNRS Materials and Construction Durability Laboratory | Duprat F.,CNRS Materials and Construction Durability Laboratory | Rougeau P.,Studies and Research Center for the Precast Industries | And 3 more authors.
European Journal of Environmental and Civil Engineering | Year: 2012

Probabilistic approach is increasingly resorted to in the design of new civil engineering structures and structural analysis of existing constructions. In this article an elementary physical and chemical model able to assess the lifetime of concrete structures subjected to carbonation ingress in natural conditions from results of accelerated tests or results from compressive strength is proposed for a probabilistic utilisation. Calculations performed on several practical applications highlight the importance of the probabilistic approach in the assessment of the reinforced concrete and pre-stressed reinforced concrete lifetimes especially with respect to the Standard context and recommendations in Eurocode 2. Results also allow the homogeneity of Eurocode 2 regarding reliability levels to be discussed and the question of a safety target index to be addressed. © 2012 Taylor & Francis. Source


Hyvert N.,CNRS Materials and Construction Durability Laboratory | Hyvert N.,Studies and Research Center for the Precast Industries | Sellier A.,CNRS Materials and Construction Durability Laboratory | Duprat F.,CNRS Materials and Construction Durability Laboratory | And 2 more authors.
Cement and Concrete Research | Year: 2010

The use of normalized accelerated carbonation tests is currently limited to the classification of concretes in terms of carbonation resistance and the results are not easily transposable to forecasting concrete carbonation in natural conditions. Common models assume that the kinetics of the carbonation front ingress in concrete is a square root function of the CO2 pressure but observations in the field generally invalidate this assumption. Based on an experimental program including carbonation tests at several CO 2 pressures, this paper shows that the amount of carbonated product depends largely on the CO2 pressure. Several experimental analyses of carbonated concrete under different pressures are confronted, to finally propose a new analytical model able to predict carbonation ingress in natural conditions using the results of accelerated tests. The model takes both the cement chemical composition and its amount in concrete into account. The carbonation kinetics dependence on CO2 pressure is considered through two underlying functions including, for the first, the dependence of the CSH carbonation rate on the pressure and, for the second, the effect of this additional carbonation on the reduction of the CO2 diffusion coefficient. © 2010 Elsevier Ltd. All rights reserved. Source

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