Ancient bricks technologies: improving the built heritage conservation at high humidity areas

Yellowish hue bricks used at the Basilica of Saint Justina of Padua (Northern Italy) produced during the 5-6th centuries (Late Antiquity times) were analysed: i) bricks located at the original placements, very humid areas where the environmental conditions remain almost constant during the day, and ii) reused bricks placed at Medieval walls exposed to insolation and quite fluctuating conditions. The first displayed good conservation state and a pale yellowish colour. The reused bricks shown granular disaggregation and a dark yellowish colour. The formation of zeolites as hydration products were detected in the pale and dark pastes. The better preservation of these bricks under humid environments, related to zeolites formation, is suggested. The data achieved could be transferred to current ceramic industry in order to produce highquality bricks particularly appropriate for the built heritage conservation located at high humidity areas.