REAPPLICATION MORTARS FOR OLD TILES: CHARACTERISTICS OF TILES AND MORTARS AND SELECTION CRITERIA

摘要

Glazed ceramic tiles have been used as facade claddings prominently since the beginning of the 19th century and they are today considered significant historic heritage. Several deterioration mechanisms threaten this important legacy. Detachment due to aging and to several external actions is one of the most dangerous mechanisms. New mortars compatible with the old tiles and old substrates are needed to reattach the loose tiles without deteriorating the glazed surface, the ceramic part, or the adjacent pieces. The tiles of the 19th century are very porous and absorbent, with variations according to the factory where they were produced. The adhesion of mortars to tiles is commanded by the penetration of the fine particles in the tiles pores, which depend on several composition factors. In this study, the characteristics of late 19th-century tiles are studied and compared with the characteristics of several types of new tiles and replicas. New mortars are formulated with the objective of reapplication of old tiles. The adhesion mechanism of substrate / mortar / tile system is analyzed and the factors involved are identified.