Compatible Mortars for the Sustainable Conservation of Stone in Masonries

Abstract

Incompatible restoration mortars used extensively in recent years have inferred irreversible damage to the original building stones of masonries. Recent research has led to the development of compatibility criteria for the restoration mortars in relation to historical materials, through the reverse engineering approach. In the restoration of historical stone masonries, apart from the issue of compatibility which is mainly of a physicochemical nature linked to ensuring breathability and avoiding preferential percolation of salt solutions to the original building stones, the issue of restoration mortars’ mechanical performance is of equal importance to achieve sustainability. An integrated methodological approach is presented aiming to the selection of the optimum compatible and performing restoration mortar for conservation/restoration interventions. The Kaisariani Monastery and the bridge of Plaka in Greece, as well as the Holy Aedicule in Jerusalem, serve as case studies in order to illustrate the methodological approach.