New recipes of mortars for Romanian architectural heritage consolidation

Abstract

For centuries, the architecture monuments consisting of masonry buildings has been built using bricks, wood, roof tiles and various mortars. The characterization of the construction materials has become of primary importance, to obtain information about the raw ingredients and building technology of the mortars, and the history of possible previous restorations. Most of these buildings support deterioration due to the environmental conditions: physical factors (temperature, wind, moisture, solar radiations, etc.), chemical factor (sulphate, nitrates, and other pollutants able to forms acid with water i.e., acid rain), and biological factor (vegetation, micro-organisms and other forms: insects, birds, animals). To find new mortar recipes, with mechanical and antimicrobial resistance, different laboratory specimens were prepared in this study, based on mortar with incorporated hydroxyapatite. They were tested from a compositional, mechanical, chromatic, and antimicrobial point of view, concluding that the best mortar is the one with 20% incorporated hydroxyapatite. Some tests as peeling, droplet water absorption, the mortar consolidant efficiency and water absorption were performed, too. The specimen surfaces were characterized by optical microscopy (OM), stereomicroscopy, mechanical measurements to evaluate the size and distribution of particles. These measurements that have been made, will serve as a critical reference for the maintenance and restoration of the buildings.