Developing realistic deterioration models

The quality of life-cycle assessments and civil and structural engineering reliability analyses depends much on the quality of the models on which they are based. In general, models for loading systems and for properties of materials are well-established. Models for structural or material deterioration are not in the same class. Ideally they must be based on good understanding of the underlying principles, have a degree of scientific validity and be calibrated to real-world data. Experimental laboratory data must be used with caution as it seldom represents long-term behaviour. Data from field experiments must be relevant and be statistically homogeneous. The influence of microbiological corrosion may be important, particularly in seawater environments. Examples of developed models for corrosion of steel, aluminium and copper-nickels are presented. Examples of practical applications discussed include steel sheet piling and cast iron piers and pipes in soils. The models also can sometimes give rise to new interpretations for observed phenomena. The latter is illustrated for the corrosion of stainless steels.