In-field measurement and numerical modelling of air leakage in concrete: From laboratory specimen to structural full-scale.

• Air leakage estimation from in situ measurement and stochastic finite element modelling. • Parameters of Klinkenberg's law evaluated from measurements under vacuum. • Consideration of the variability of drying parameters for a reliable quantification. • Estimation of an accurate mean response of the diffuse air leakage under pressure. • Estimation of the quantification of uncertainties over time. This work estimates air leakage through concrete porosity for structures by using data obtained in field combined with stochastic finite element (SFE) modelling. For this purpose, a methodology is proposed to evaluate permeability under representative over-pressurization conditions based on in-field measurements under vacuum. This makes it possible to investigate the air leakage through the inner wall of a 1:3 scaled nuclear vessel named the VeRCoRs mock-up. Measurements are made for over 80 points scattered on the external face of the inner wall of the structure. Based on the data collected, a statistical analysis quantifies the spatial variation of permeability and contributes to the building of an SFE model of air leakage at the structural scale. Measured and predicted data are in good agreement on the service life of the structure. This shows the relevance of combining in-field measurements during an operational phase and the SFE modelling for better evaluation of the structural performance. The lessons learnt from the present work could be useful for the assessment of all structures with durability or mechanical issues that induce a continuous loss of tightness. [ABSTRACT FROM AUTHOR]