Characterization of calcarenitic stones in monumental masonry buildings of Cosenza (Italy)

Abstract

The aim of this study is to analyze the deterioration of the stone commercially known as “Mendicino calcarenite”, used for the building of two important portals in Cosenza (Italy), belonging to the Church of “San Francesco di Paola” (XVI century) and “Palazzo Bombini” (XVII century), evaluating, by means of site and laboratory tests, changes in petrophysical and mechanical properties. Building type analysis of stone decay was obtained through a field survey and direct measurements. Mechanical properties have been assessed on site by means of Schmidt Hammer Hardness Test. Chemical and morphological SEM analyses have been performed in laboratory in order to identify anomalies in rock structure, as well as to compare unweathered and deteriorated specimens. Unweathered calcarenitic samples come from the active quarry of San Lucido, belonging to the geological Unit of the Tortonian-Messinian sedimentary succession of the High Crati Valley. Furthermore accelarated ageing test by salt crystallization have been performed on quarry samples in order to assess durability of this material. Tests results have provided a preliminary comprehensive understanding of the level of deterioration of the examined case studies, how deterioration can affect physical and mechanical properties of the building stone and an evaluation of the compatibility to restore the most deteriorated parts with a similar quarried lithotype.