Consolidation with ethyl silicate: how the amount of product alters the physical properties of the bricks and affects their durability

We evaluated the consolidating capacity of ethyl silicate in three types of bricks fired at 800, 950 and 1100 °C. We chose two concentrations of product, at 25% and 50%, diluting the product in white spirit to estimate whether greater dilution enables the product to penetrate deeper into the bricks, or whether a higher concentration leads to better consolidation of bricks. The application of ethyl silicate caused bricks porosity to decline and their compactness to increase. These changes were more accentuated as the concentration of the product increased. The pore size distribution not changed substantially except that there were fewer of the smallest pores. The color and the lightness of the pieces changed after application of the consolidant, albeit slightly. The durability of bricks improved as manifested by the results of the salt crystallization test. In general, the longest-lasting pieces were those treated with 25% ethyl silicate.Se ha evaluado la capacidad consolidante del silicato de etilo en tres tipos de ladrillos cocidos a 800, 950 y 1100 °C. Se eligieron dos concentraciones de producto, al 25% y 50%, diluyéndolo en white spirit para estimar si más dilución favorece una penetración más en profundidad del producto o si una mayor concentración produce una mejor consolidación de los ladrillos. El silicato de etilo ha causado una disminución de la porosidad y un aumento de la compacidad de los ladrillos, acentuándose estas modificaciones con mayor concentración de producto. La distribución porométrica no ha cambiado de forma sustancial, disminuyendo los poros más pequeños. Color y luminosidad de las piezas han modificado ligeramente tras la aplicación del consolidante. Los ladrillos consolidados han mejorado su durabilidad frente al envejecimiento acelerado producido por las sales. En general, las piezas más duraderas han resultado ser las tratadas con el 25% de silicato de etilo.This study was financially supported by Research Group RNM179 of the Junta de Andalucía and by Research Project MAT2016-75889-R

Characterization of Classical Construction Materials used in Ethiopian Architecture for the Restoration of their Historic and Artistic Heritage

Draft previo a publicación en International Journal of Architectural Heritage: Conservation, Analysis, and RestorationMany architectural constructions with heritage value around Lake Tana (Ethiopia) were erected by the Jesuits in the 17th century, who used techniques and materials from the classical Roman tradition. The study of its state of conservation and their building materials (masonry concrete, masonry mortar, painted plaster, masonry bricks, and masonry stone) has revealed the great constructive technique and the high quality of binders used by them. Various samples from each monument were taken and subjected to chemical analysis (FRX), X-ray diffraction tests, polarized light optical microscopy, scanning electron microscopy, ultrasounds, and colorimetry tests. The composition results provided important information about the provenance of the materials used by the Jesuits. Their air lime binders were also of particular interest due to the addition of locally sourced diatomite earths to create a product with high mechanical resistance and durability. The techniques introduced by the Jesuits can be used today in the sustainable, economical restoration of heritage in Ethiopia and adjacent regions.This work was supported by the REMINE Programme for Research and Innovation Horizon 2020 Marie Skłodowska-Curie Actions and Project MAT2016-75889-R of the National Plan for Scientific Research, Development and Technological Innovation (Ministry of Science and Technology) and was carried out under the auspices of Research Groups RNM 0179 and HUM 629 of the Junta de Andalucía