Finite element modeling of cracking in concrete due to localized corrosion in the reinforcement

Abstract

Based on studies with finite element method, a model able to predict the quantity of steel corrosion (rcrit) necessary for the first visible crack appearance in the surface of the concrete cover was obtained. For the finite element analysis the software ANSYS was used, which has the element SOLID65, with which is possible to model plain concrete, since has the capacity to show crushing in compression and to cracking in tension. The case of the oxide layer is modeled by means of contact elements CONTA174 and the steel with SOLID65, but without the crushing and cracking options. The obtained model is in function of the free cover, diameter of the reinforcement, and concrete type and the longitude of corrosion, known as anodic longitude. The results show the great influence that has the localized corrosion (small-size anode vs large-size cathode) on the prediction of rcrit, and that effect is only possible to analyze it in a three-dimensional way. Likewise, the efficiency of using the contact elements CONTA174 to represent the growth of oxide is shown. The obtained model explains in 92% the phenomenon and which is compared with experimental results found in literature.