Continuum Modelling of Corrosion Processes in Reinforced Concrete at Microscale

摘要

The chloride induced concrete degradation is a well-known issue in the infrastructure and scientific community. There is a growing industrial need of a comprehensive numerical tool to accurately model the corrosion process and predict the service life of structures. The study at hand will focus on the continuum modelling of corrosion process at the microscale with further possibilities to be linked to atomistic, mesoscale and macroscale computational models. The continuum corrosion model is applied on high performance concrete (HPC) substrate and its exposure to chloride ingress in submerged conditions, thereby incorporating the main chemical species present in such an environment. Immobilization of chloride ions inside concrete, together with the electrochemical and chemical aspects of the main involved chemical species especially during metal dissolution and rust formation are considered. Time dependent growth of the corrosion products is modelled in terms of surface coverage and layer thickness. The corresponding barrier properties due to rust formation are considered in terms of porosity contribution from each corrosion product. The resistive surface effects of the rust layer are in turn coupled with the exchange current densities related to anodic and cathodic reactions. Geometry changes due to cumulative effect of metal dissolution and rust generation are considered by boundary mesh translation using an arbitrary Euler Lagrange (ALE) system. Strain and Stress fields generated at the rebar-concrete interface can be directly computed from these model parameters. The final approach will produce a more realistic picture of the corrosion process inside concrete and has not been studied so far in such detail. The talk positions the current status of our work towards accurate service life prediction of reinforced concrete structures in terms of rebar loss more accurately and precisely.