Contributions of Correspondence Analysis in the Use of Natural Stones

Abstract

The use and application of natural stones depends on many aspects that involve not only their lithologies, physical-mechanical properties and chemical composition, but also take in consideration aesthetic, social, cultural and economic criteria. It is possible to establish a classification of natural stones based upon the variables listed above, and thus build an information matrix in which the lines identify each of the lithotypes and the columns refer to the different properties (some of a quantitative nature and others of a qualitative nature). In this work, we propose to illustrate a methodology that, using techniques in the field of multivariate statistics (Correspondence Analysis), and according to the criteria defined at the outset, allows different users of natural stones to select alternatives to the use of a lithotype, replacing it by another that corresponds to all the previously defined multi-criteria. Our case study was based on data presented in the 142 technical sheets, which make up the 4 volumes of the Portuguese Natural Stones Catalogue, (Laboratory of the General Directorate of Geology and Mines, S. Mamede de Infesta, 1983, 1984, 1985 and 1994). The values of nine physical-mechanical properties, the percentages of oxides of major elements determined in the chemical analysis and the macroscopic description were the variables considered for this statistical analysis. Keywords: Natural Stones; Correspondence Analysis, Physical-mechanical Properties, Chemical Analysis, Lithological Description