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Chloride diffusion coefficients through concrete partially submerged and partially exposed to the atmosphere



Author(s): G. de Vera, M.A. Climent, C. Antón, I. Sánchez, C. Andrade
Paper category: Workshop
Book title: International RILEM Workshop on Integral Service Life Modelling of Concrete Structures
Editor(s): R.M. Ferreira, J. Gulikers, C. Andrade
Print ISBN: 978-2-35158-058-5
e-ISBN: 978-2-35158-090-5
Publisher: RILEM Publications SARL
Pages: 23 - 30
Total Pages: 8
Language: English


Abstract: 
Chloride diffusion coefficient through concrete D is an important parameter related with reinforced concrete durability. It can be measured with different test methods based on natural diffusion, in which a water saturated concrete sample is placed in contact with a chloride solution, and a chloride profile is obtained after a time. Diffusion is assumed to be the main transport mechanism and data fitting to the error function solution of Fick’s second law, is used to determine the D value. A fully water saturated sample is needed in order to assure a diffusion transport mechanism, otherwise other transport mechanisms as capillary sorption or wick action could act. In a ponding test a pool containing the chloride solution is attached on the concrete sample. Storage conditions during chloride exposure could affect concrete water saturation and hence the D value may be affected. The aim of this work is to study the effect of the storage conditions on the diffusion coefficient value when a ponding test is performed. The following environments in contact with sample during chloride exposure have been studied: (i) 100% relative humidity (RH), (ii) atmosphere with a RH generated by a 1M NaCl solution (approx. 96%), (iii) 75% RH, and (iv) sample sealed with polyethylene film. A dependency of D with storage conditions is observed. The higher the RH, the lower the D value. This result shows that at lower RH, transport mechanisms others than diffusion could act. D value obtained with PE film sealing lays between D values obtained with environments (ii) and (iii).


Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00