The use of Mount Etna volcanic ash in the production of bricks with good physical-mechanical performance: converting a problematic waste product into a resource for the construction industry

Volcanic ash emissions are responsible for serious damage to buildings. They can also affect vehicle traffic, cause airport closures and may be hazardous for human health. To verify the effects of the potential addition of this residue to the mixture used in the production of bricks, a detailed study of the clayey material, the volcanic ash and the bricks fired at 800, 950 and 1100 ºC was conducted, assessing chemical, mineralogical, physical, mechanical and durability aspects. The addition of 10 to 20 wt.% of volcanic ash delayed the appearance of new phases during brick firing and made them less porous. The bricks maintained their orange colour and became more compact as the firing temperature increased due to sintering and vitrification processes. The addition of volcanic ash reduced the strength of the bricks although the values were always above the limits recommended for construction work with ceramic materials. Bricks with added volcanic ash increased their resistance to decay due to salt crystallization and the general behaviour of the bricks improved when they were fired at high temperatures.Grupo de Investigación RNM 179 de la Junta de Andalucí

Technical quality of solid bricks made using clayey earth with added coffee grounds and fly ash

This paper analyses the effects of the addition of organic (coffee grounds) and inorganic (fly ash) residues to a clayey soil rich in quartz and other silicates used as a raw material in brick production. To this end the mineralogy, texture, durability and physical and mechanical properties of solid bricks fired between 800 and 1100 ºC were studied. The results show that as the firing temperature increased, the phyllosilicate content decreased and mullite appeared. The matrix became less birefringent due to gradual vitrification of the samples, especially after 950 ºC. Vitrification resulted in more compact, less porous samples. The addition of residues did not affect the mineralogy, but it did alter certain physical parameters such as colour and porosity. The largest colour differences were detected after the addition of fly ash, which usually caused a whitish patina to develop on the surface of the fired bricks, while the highest porosity values were detected in bricks with coffee grounds, significantly reducing the bulk density. The increase in firing temperature improved the mechanical resistance and durability of all the bricks regardless of their composition.Grupo de Investigación RNM179 de la Junta de Andalucí

Roman brick production technologies in Padua (Northern Italy) along the Late Antiquity and Medieval Times: Durable bricks on high humid environs

Production technologies of Roman to Medieval times bricks on the city of Padua were addressed by means of a multi-analytical approach, consisting in Spectrophotometry, X-Ray Fluorescence (XRF), Powder X-Ray Diffraction (PXRD), Polarized Optical Microscopy (POM) and Scanning Electron Microscopy (SEM- EDS). The Early-Christian (5-6 th centuries) and Romanesque (12-13 th centuries) areas of the Basilica of Saint Justine of Padua (5/6-16 th centuries), and the remains of the Roman necropolis (1-3/4 th centuries) still preserved under the basilica, were selected to collect the bricks in order to define possible differences between the materials used for the various building phases. The walls are mainly shaped by yellow (with pale and dark hue) and beige colored bricks with an overall good conservation state. The ceramic bodies of this type of bricks showed the development of high-temperature phases but a low sintering degree was achieved. Moreover, secondary phases such as zeolites and calcite were formed, within almost the pale-yellow bodies and intensively precipitated through the groundmass of the beige bricks, respectively. Mg-rich calcareous clays and chloritic-illitic clays were used, firing temperatures of or over 900 °C were reached and more porous ceramic bodies were produced when higher was the carbonate content on the raw clays. A lesser carbonate content of the base clays and/or the decrease in the firing temperatures were the main technological modifications progressively accomplished, leading to color changes on the ceramic bodies from yellow to beige hue. The Roman production technologies might be largely inherited by the brick makers during the Late Antiquity and Medieval times in the city and the reuse of more an- cient bricks during the Medieval Times was confirmed. Such reuse operations have allowed to observe that under high humid conditions the yellow hue bricks have been rather good preserved, while when exposed to insolation and fluctuations of the environmental conditions a significant granular disaggrega- tion -with the concomitance darkening of the color pastes- is developed. The color of bricks may entail an identifier of a specific construction period of the city and durable bricks from local clays, especially suitable for high humidity areas and that may preserve the aesthetical values of the city of Padua, may be currently produced.European Union's Horizon 2020 Research and Innovation Programme, under the Marie Sklodowska-Curie Individual Fellowship 836122Junta de Andalucia RNM17

Growth of metastable phases during brick firing: mineralogical and microtextural changes induced by the composition of the raw material and the presence of additives

Research Project MAT2016-75889-R Junta de Andalucía Research Group RNM179 Departamento de Mineralogía y Petrología (Universidad de Granada) Departamento de Didáctica de las Ciencias Experimentales (Universidad de Granada) Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR) Grupo de Investigación HUM613 (Didáctica de las Ciencias Experimentales y de la Sostenibilidad)We thank Cerámica Castillo Siles for providing the raw material used to prepare and fire the bricks and Cervezas Alhambra S.L. (Granada) for providing the calcined diatomite sludge with yeast. We are grateful to Nigel Walkington for his assistance in translating the original text.Mineralogical and textural changes experienced by solid bricks made without additives and others made with added halite or with added calcined diatomite sludge, and fired in an electric oven at 800, 950 and 1100°C have been studied. Different analytical techniques (x-ray fluorescence, thermogravimetric analysis, x-ray diffraction, polarized optical microscopy and scanning electron microscopy) were used to reconstruct the changes that took place inside the bricks from a mineralogical and textural point of view. These changes are similar to those that take place in nature during pyrometamorphism. Carbonates decompose and react with silicates to form gehlenite, diopside and wollastonite. Plagioclase enriches in calcium and quartz concentration diminishes. Clay minerals favour the melting of matrix and the appearance of mullite. K-Feldspar changes from microcline to sanidine. The extent of vitrification increases in line with the increase in the firing temperature. When halite is added, new silicates appear earlier at lower firing temperatures and molysite is formed. Calcined diatomite sludge contains cristobalite, which becomes part of the mineralogy of the bricks. The newly-formed phases contain certain chemical elements that are not normally found in their standard chemical composition.This study was funded by Junta de Andalucía Research Group RNM179 and by the Research Project MAT2016-75889-R

Production Technologies of Ancient Bricks from Padua, Italy: Changing Colors and Resistance over Time

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.Marie Sklodowska-Curie grant agreement No 836122CLAYONRISK ProjectResearch Group of the Junta de Andalucía RNM179MSC Actio

Pomace from the wine industry as an additive in the production of traditional sustainable lightweight eco-bricks

This study has been funded by Junta de Andalucía Research Group RNM179 and by Research Projects PPJIB2022-17 and B-RNM-188- UGR20 of the Regional Ministry of University, Research and Innovation of the Junta de Andalucía and FEDER, a way of making Europe. We are grateful to Nigel Walkington for his assistance in revising the English text of the manuscript and to three anonymous reviewers for their helpful suggestions. We also thank Bodegas Navarro (www.bodegasn avarro.es), who supplied the wine pomace, and Ceramica Castillo Siles (www.ceramicacastillosiles.es), who provided the raw materials from Viznar and Guadix. We are also grateful to Junta de Andalucía Research Group HUM629.This research examines fired clay bricks made with waste pomace from the wine industry as an additive in brick production. To this end, we analyse and discuss the chemical, mineralogical, textural and physical-mechanical behaviour of fired bricks made with three concentrations of wine pomace (2.5, 5 and 10 wt%) and at three different firing temperatures (800, 950 and 1100 degrees C) and evaluate their durability to salt crystallization. Variations in colour were also examined. The firing process resulted in the decomposition of phyllosilicates and carbonates, the crystallization of Fe oxides and the appearance of high-temperature Ca- (and Mg-) silicates phases such as gehlenite, wollastonite, anorthite and diopside. The bricks made with added wine pomace had very similar mineralogy to the control samples made without it. The bricks made with added wine pomace were lighter than the control samples and underwent less linear shrinkage during the drying process. Particles in the wine pomace were consumed during firing, leading to the appearance of voids. The bricks made with this additive had higher levels of water absorption and poorer mechanical strength. The greatest colour differences were detected after increasing the amount of waste, which generally resulted in yellower bricks. The increase in firing temperature resulted in an improvement in mechanical resistance regardless of the composition of the bricks. However, bricks fired at 1100 degrees C made without additive are more resistant to damage caused by salts than those made with wine pomace.Junta de Andalucia RNM179Regional Ministry of University, Research and Innovation of the Junta de Andalucia PPJIB2022-17, B-RNM-188- UGR20European Union (EU) Spanish GovernmentFEDERJunta de Andalucía Research Group HUM62

Mineralogical and petrographic characterization of the Cerrillo Blanco Iberian sculptures

This research was funded by the following projects: (ECODIGICOLOR), grant number TED2021‑132023B‑I00, supported MCIN/AEI /http://dx.doi.org/10.13039/501100011033 and Unión Europea NextGenerationEU/ PRTR (Proyectos estratégicos orientados a la transición ecológica y digital) and project “Aplicación avanzada de las algas procedentes de la Alhambra y el Generalife en técnicas artísticas y de conservación‑restauración, (FICOARTE2), grant number P18‑FR‑4477, supported by Consejería de Universidad, Investigacion e Innovación, Junta de Andalucía, Programa FEDER, “Andalucía se mueve con Europa”, Grant PID2020‑113022GB‑I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, by the “European Union”.The archaeological heritage at Cerrillo Blanco (Porcuna, Spain) is made up of 27 sculptural ensembles and hundreds of fragments dated between the seventh and second centuries BC. They represent a fundamental milestone in Iberian art and culture. Despite their relevance, no scientific studies have been carried out to date in order to fully understand the materials, intentions and techniques that led to their creation. This is a study carried out on original pieces from the Archaeological Museum of Jaen using stereoscopic optical microscopy (SOM), polarised optical microscopy (POM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy with energy dispersive x-ray analysis (FESEM-EDX) and spectrophotometry (SF). The results obtained provide new information on the material composition of this important legacy of the Iberian civilization as well as its main alteration factors.MCIN/AEI TED2021-132023B-I00, PID2020-113022GB-I00Unión Europea NextGenerationEU/ PRTR TED2021-132023B-I00Junta de Andalucía, FEDER, "Andalucía se mueve con Europa" P18-FR-4477"ERDF A way of making Europe" Unión Europea PID2020-113022GB-I0

Mineralogical, Textural and Physical Characterisation to Determine Deterioration Susceptibility of Irulegi Castle Lime Mortars (Navarre, Spain)

Archaeological lime mortars from the Tower Keep and West perimeter wall of Irulegi Castle (Navarre, Spain) were analysed to determine susceptibility to deterioration. Chemical, mineralogical, textural and physical characterisation was performed by different tests and multianalysis techniques in order to determine the intrinsic features of the original historical mortars at the castle. Samples from the Tower Keep are more prone to deteriorate compared with the West perimeter wall due to high water absorption capacity and high porosity. A high degree of pore interconnection, high desorption index and the presence of high pore volume in the 0.01 to 1 mu m size range affect the mortar durability since pores retain water longer inside the mortar. Local environment conditions with persistent annual rainfall, high humidity and temperature variations contribute to the decay process of the original mortar. Characterisation of historical mortars not only allows better understanding of susceptibility to deterioration but also helps the design of compatible and durable repair mortar for future interventions on historical heritage. Compatibility of new materials with the historical mortar will be ensured by studying mortar characteristics and properties.This study was possible thanks to the financial support of Junta de Andalucia Research Group RNM179 and Research Project MAT2016-75889-R

The Influence of the Type of Lime on the Hygric Behaviour and Bio-Receptivity of Hemp Lime Composites Used for Rendering Applications in Sustainable New Construction and Repair Works

The benefits of using sustainable building materials are linked not only to the adoption of manufacturing processes that entail reduced pollution, CO2 emissions and energy consumption, but also to the onset of improved performance in the building. In particular, hemp-lime composite shows low shrinkage and high thermal and acoustic insulating properties. However, this material also shows a great ability to absorb water, an aspect that can turn out to be negative for the long-term durability of the building. For this reason, the hygric properties of hemp-based composites need to be studied to ensure the correct use of this material in construction and repair works. The water absorption, drying and transpirability of hemp composites made with aerial (in the form of dry powder and putty) and hydraulic limes were investigated here and related to the microbial growth induced by the water movements within the material. Results show that hemp-natural hydraulic lime mixes exhibit the highest transpirability and drying rate, the lowest water absorption by immersion and capillary uptake and the least intense microbial attack and chromatic change. A microscopical study of the hemp shives also related their great ability to absorb water to the near-irreversible swelling of their structure under dry-wet conditions.The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 326983 (NaturALiMe), and the Spanish project MAT-2012-34473 of the Ministerio de Ciencia y Competitividad. Author MB, owner of the CANNABRIC company, had some role in the design and preparation of mortar samples and in the preparation of this manuscript, but did not have any additional role in data collection and analysis

Estudio mineralógico-petrográfico y físico-mecánico de ladrillos macizos para su aplicación en intervenciones del patrimonio histórico.

Tesis Univ. Granada. Departamento de Mineralogía y PetrologíaEste trabajo estuvo financiado por los proyectos MCT: MAT2000-1457 y FEDER 1997-0331 (MAT