Correlation between stone weathering and environmental factors in marine atmosphere

Construction materials in historic buildings suffer from various physicochemical decay processes governed by their interaction with environmental parameters leading to quite a great variety of deterioration forms at several scales. In the present work, the establishment of a method for a statistically reliable correlation between the particular parameters which compose the microenvironment and the resulting decay form is attempted. The case of an extended monument, like the medieval city of Rhodes, where various characteristic types of weathering can be distinguished in relevance with the particular laws governing the relation between environmental and microclimatic conditions and materials, could act as a pilot. The results of ion chemical analysis for soluble salts along with sea and sun exposure and air flow, which control transport and evaporation of solutions in the stone, have been included in the data matrix describing the statistical problem. Discriminant analysis is employed using as data vector the above variables and entering as classification factor the variable Dectype. It is possible to classify a new case by evaluating each function, through the classification function coefficients, and assigning the case to the group corresponding; to the highest function value. This classification is validated by the chemical analysis and the in situ study as well. Statistical analysis and especially multivariate methods could provide a technique for predicting what type of weathering would be expected according to the micro-environmental conditions at various locations. Hence, the directions of a conservation plan could be ascribed and evaluated accordingly.