Chemical and physical investigations of historic mortars in St. John’s Church (Cesis, Latvia)

Abstract

This paper deals with the stone material investigation of St. John’s Church, located in Cesis, the city in central region of Latvia. Following aspects were considered – chemical, physical and granulometrical characterization of historic mortars, as well as the level of soluble salts in the masonry. The chemical and physical properties of the historical mortars were characterized by visual observation, granulometric analysis, classical wet chemical analysis, XRD, SEM and hydro tests. The results showed that the historic mortars are based on two types of weakly hydraulic lime – calcitic and dolomitic – with brick dust additive. The main crystallized salt in the object was KNO3. The aim of the investigation was to provide compatibility of restoration materials and sustainability of the ancient building.