Bond between 19th Century lime mortars and glazed ceramic tiles

[Display omitted] •Ceramic materials produced in 19th Century for the cladding of facades are studied.•The bond between highly absorbent ceramic tiles and lime mortars is evaluated.•Adherence extension on the tile/mortar interface is measured at mesoscopic scale.•The bond strength is directly proportional to the adherence extension.•The greatest influence on bond was exerted by the aggregate grain size and shape. This paper relates the study of the bond mechanism between lime mortars and glazed tiles. These materials were sampled from facades in Ovar-Portugal, which had been clad in the 19th Century. A thorough characterization of mortars and tiles was performed as well as an analysis of the interface between these materials, based on the quantification of the bond extension and strength. As main results, it can be stated that the bond strength values are directly related to the adherence extension (effective adherence surface) measured at mesoscopic scale and that the greatest influence on bond was exerted by the aggregate grain size and shape.