Modeling Deterioration of RC Structures Due to Environmental Conditions

Abstract

Chloride-induced corrosion of steel reinforcement in concrete, creep and shrinkage and freezing-thawing are some of the major causes responsible for deterioration of reinforced concrete (RC) structures. The repair of damaged structures results in relatively high direct and indirect costs. Therefore, to predict their durability it is important to have a numerical tool, which is able to account for the above mentioned processes and their consequences for the structural safety. In the paper a recently developed coupled Chemo-Hygro-Thermo-Mechanical model for concrete is briefly discussed. The model is implemented into a 3D finite element code and it is aimed to model processes related to corrosion of steel reinforcement, freezing-thawing and creep and shrinkage of concrete. The macro-cell corrosion of steel reinforcement accounts for all relevant processes before and after depassivation of reinforcement and it is coupled with the mechanical model for concrete, which is based on the microplane model. Loading due to freezing-thawing of concrete is formulated in the framework of poromechanics. Drying creep of concrete is simulated based on the hygro-mechanical model at the meso scale. Investigated is the influence of the interaction between non-elastic deformations of cement paste (basic creep and shrinkage), load induced damage and heterogeneity of concrete. The application of the model is illustrated on several numerical examples.