Influence of the bars position in the reinforced concrete for the prediction of the chloride concentration in the layer steel-concrete

Author(s): Fabiano Tavares, Carmen Andrade
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 255-262
Total Pages: 813
Language: English

Abstract: Corrosion of reinforcing steel in concrete due to chloride ingress is one of the main causes
of the deterioration of reinforced concrete structures. The corrosion process is accompanied by
an increase in volume, which induces tensile stresses in the surrounding concrete, which may
result in cracking and spalling of the concrete cover if the concrete tensile strength is exceeded.
The mathematical formulation idealized the corrosion sequence as a two-stage process: an
initiation stage, during which chloride ions penetrate to the reinforcing steel layer and
depassivate it, and a propagation stage, in which active corrosion takes place until cracking of
the concrete cover. Until now the process of chloride penetration has been modelled assuming
semi-infinite boundary due to the thickness of the concrete is usually comparatively large,
however this is not the case at the rebar position as the chlorides find the bar surface a do not
progress more being accumulated in the steel/concrete interface. The study in this paper shows
a deterministic analysis of the chloride diffusion process by the finite element method (FEM)
which numerically solves Fick’second Law taking into account the position of the reinforcing
bar. The results show that the chloride threshold are reached before than if semi-infinite
conditions are considered and that the stresses produced are different than if generalized
corrosion is simulated, aiming into the calculation of shorter service life. The finite boundary
should be the condition used for the calculation of time to corrosion if second Fick’s law is
applied.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00