Decay of buildings is often related to corrosion of metallic reinforcements. If wet conditions occur on the surface of steel reinforcements, corrosion can start, unless the inserts are protected by the alkalinity of the environment. Corrosion may weaken reinforcements and produce expanding oxides that lead to the detachment of covering materials, thus being harmful for the durability of the construction and challenging for its restoration. When dealing with heritage buildings the problem becomes even more complex due to the need of non-invasive and reversible techniques. Here the only possibility is often to limit the corrosion rate by controlling moisture and temperature conditions in the assembly.
Starting from this point, the corrosion-hygrothermal model is developed with the aim to describe the effect of the environmental and material factors affecting corrosion of steel inserts embedded in building components in terms of quantities familiar to building physics. It is meant to allow the prediction of corrosion rate of steel inserts in porous building materials over the time, depending on temperature and RH at the steel surface. The model has been validated through several laboratory tests, showing a good agreement between measured and simulated results. It allows both preventive conservation/restoration of cultural heritage buildings and safe design of new durable building components.
Please notice that the model is not suitable for predicting atmospheric or chloride induced corrosion.
The basics of the model are discussed in:
- Marra. “Influenza dell’ambiente sulla corrosione degli inserti di acciaio nelle murature antiche”. PhD Dissertation. Politecnico di Milano. Milano, 2012.
- Bertolini, M. Carsana, B. Daniotti, and E. Marra. “Environmental Factors Affecting Corrosion of Steel Inserts in Ancient Masonry”. In: Durability of Building Materials and Components. Ed. by V. P. d. de Freitas and J. Delgado. Vol. 3. Building Pathology and Rehabilitation. Berlin, Heidelberg: Springer-Verlag, 2013, pp. 229–252. doi: 10.1007/978-3-642-37475-3_9
- Marra,D. Zirkelbach, and H. M. Künzel. “Prediction of Steel Corrosion in Porous Building Materials by means of a New Hygrothermal Model”. In: Energy Procedia (2015). doi: 10.1016/j.egypro.2015.11.144
- Carsana, E. Marra, and L. Bertolini. “Corrosion behaviour of metal inserts in simulated ancient masonry mortars”. In: Construction and Building Materials 95 (2015), pp. 457–466. doi: 10.1016/j.conbuildmat.2015.07.110