Fig. 1
From: A mixture theory-based concrete corrosion model coupling chemical reactions, diffusion and mechanics
A concrete sewer pipe is corroded by sulfuric acid containing air at the top and by the acidic sewage at the tidal region of the sewage-air interface. The sulfuric acid is created by biodegradation of bio-matter in sewage. Extended corrosion leads to erosion of the concrete and potentially to sewer pipe collapse. Our model is meant to describe the beginning of corrosion, as shown in the small square, allowing the simplifications from a pipe to a plate layer, as shown in the large square. This simplification reduces a 3-D concrete corrosion model into a 1-D model only dependent on the spatial variable z. The thickness, h(t), of the mixture layer changes over time due to both influx of material and the chemical reaction in the mixture