A mushy region in concrete corrosion

In this work a mathematical model already known for the corrosion of sewer pipes is further considered, enriched and an approximate analytical solution is given based on a quasi-steady approximation. Furthermore an extension of this model is constructed allowing the formation of a mushy region, i.e. a region in which the material is only partly corroded throughout the process. This more general model is derived via an averaging process by microscopic considerations and has the form of a macroscopic phase field model. The derived model in its various forms is solved numerically with a finite element method and the results, predicting corrosion within a reasonable range, are presented.