Quality ranking of twelve columnar basalt occurrences in the northern portion of the Paraná Basin-Brazil

This paper presents results obtained from a study of basal degrading conducted on samples of basaltic rocks found in the northern part of the Paraná Basin in the State of São Paulo, Brazil. To meet the objectives of the study, natural and accelerated alteration tests were carried out followed by a comparison of the quantitative analysis of the two alteration processes. The combined analysis of the information proved to be very useful tool for rock qualification and the quantification of alterability, thus providing a basis for comparative analysis of massive and columnar jointed basalt relative to their use as aggregate for civil construction purposes.