Production Technologies of Ancient Bricks from Padua, Italy: Changing Colors and Resistance over Time Pérez Monserrat, Elena Mercedes Maritan, Lara Garbin, Enrico Cultrone, Giuseppe V. Archaeometry Brick fabrics Durability Porosity Sintering Urban coloring Representative and very uneven texturally bricks having yellow/beige or pale or dark red colors from the Renaissance walls (16th century) of Padua, Northeast Italy, were studied by means of colorimetric, petrographic (MOP), chemical (XRF), mineralogical (PXRD) and microstructural analysis (FESEM-EDS). Starting from the color measurements of the ceramic bodies, the manufacturing technologies and their influence on the physical behavior and durability of the bricks were established. The porous system was characterized by means of hygric tests and mercury intrusion porosimetry; the compactness and structural anisotropy were defined through ultrasound velocity; the uniaxial compressive strength was determined; and durability to salt crystallization and frost action of the bricks was assessed. Mg- and Ca-rich illitic clays fired at temperatures ≥900 ◦C were used to manufacture the beige hue bodies, while the pale red bricks were made out with Ca- and Fe-rich illitic clays fired at 850–900 ◦C. A lower carbonate content on the base clays and a lower firing temperature were the main causes responsible for the changing colors from beige to red hue. The increase of the red color was associated to higher silicate inclusions content and lower development of reaction rims around grains. The low sintering degree achieved yielded highly porous bodies with diverse porous systems, leading to differential physical performance and durability of the bricks that may turn out beneficial for the conservation of the historic walls. 2021-07-09T10:13:43Z 2021-07-09T10:13:43Z 2021 info:eu-repo/semantics/article Pérez-Monserrat, E.M.; Maritan, L.; Garbin, E.; Cultrone, G. Production Technologies of Ancient Bricks from Padua, Italy: Changing Colors and Resistance over Time. Minerals 2021, 11, 744. https:// doi.org/10.3390/min11070744 http://hdl.handle.net/10481/69626 10.3390/min11070744 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI