Finite element modeling of cover cracking in reinforced concrete structures due to non-uniform steel corrosion

Author(s): E. Chen, C. K. Y. Leung
Paper category: Proceedings
Book title: Proceedings of the Seventh International Conference on Concrete under Severe Conditions – Environment and Loading
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 211-222
Total Pages: 12
Language : English

Abstract: It is well known that steel corrosion can cause serious degradation problems in reinforced concrete structures. In the literature, many theoretical investigations have been performed with the objective to predict the service life of RC structures with corroding steel. Most of these models assumed uniform corrosion around the steel for simplification. In real RC structures, corrosion should start at the position nearest to the free surface exposed to natural chloride environment, and gradually spreads to other locations. As a result, the chloride attack/penetration and the build-up of rust around the bar are far from being uniform. In this paper, the diffusion process which induces steel corrosion and the mechanical process under rust expansion are linked together to analyze the development of cracking in the concrete cover. Three different cases, including (i) a single bar in a member, (ii) a row of bars and (iii) a corner bar, are separately studied. The diffusion equation is first solved to deduce the corrosion initiation time at each point around the steel. The distribution and thickness of rust around the steel bar can be then obtained by specifying an appropriate rust formation rate. Knowing the rust distribution around the steel at different corrosion levels, the failure of concrete cover due to rust expansion is analyzed by finite element analysis. The cracking mechanism of the three cases is first examined. To highlight the necessity to consider non-uniform corrosion, the surface crack width evolution under non-uniform corrosion for the single rebar case is compared with that under uniform corrosion.

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