Production Technologies of Ancient Bricks from Padua, Italy: Changing Colors and Resistance over Time
Metadatos
Afficher la notice complèteEditorial
MDPI
Materia
Archaeometry Brick fabrics Durability Porosity Sintering Urban coloring
Date
2021Referencia bibliográfica
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
Patrocinador
Marie Sklodowska-Curie grant agreement No 836122; CLAYONRISK Project; Research Group of the Junta de Andalucía RNM179; MSC ActionRésumé
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.