Gypsum alabaster is one of the most prominent stones used in European sculpture in medieval and early modern times. Many historical quarries are documented through textual and material evidence (Lipińska, in press) but some remain enigmatic. The “albâtre de Lagny”, a town situated on the banks of the River Marne in the eastern suburbs of Paris, has been mentioned throughout the 19th century as source for sculpture, notably for the numerous altarpieces now known as English production. This is in obvious contradiction to what 20th century research found out about the workshops in and around Nottingham using local material. The systematic reference to Lagny, invalidated by material fingerprinting for those and numerous other sculptures, has discredited these earlier sources. It has even been questioned if the gypsum quarried along the Marne River has ever been used for sculpture and the Lagny alabaster was qualified as legend (Bresc-Bautier, 2018; Jugie et al., 2024).
The discovery of an unpublished manuscript, preserved at the Museum of Natural History (MNHN) in Paris, written by one of the most prominent figures of political, legal and scientific life of the late 18th century, Chrétien Guillaume de Lamoignon de Malesherbes (1721-1794) , sheds a new light on this deposit. Lamoignon provides a detailed description of an alabaster-grade layer in the gypsum quarries of Thorigny, north of Lagny, based on his personal observations and interviews with the workers, a precise stratigraphy, and a list of collected samples. He also visited a workshop in the very centre of Paris using the “Lagny alabaster”, at this time undoubtedly for decorative objects rather than for figurative sculpture. The timeframe for this manuscript is still uncertain, we can situate it between the French translation of the “Lithogeognosia” of Pott in 1753, the 1759 alabaster essay of Daubenton, both cited by Lamoignon, and his death on the guillotine in 1794.
After transcribing the manuscript and precisely locating the historical quarry, we investigated French collections of geological reference materials and found indeed samples of “Lagny alabaster” from the 19th and early 20th century at the MNHN and the BRGM. We are currently completing our corpus of isotope fingerprints of this deposit (Kloppmann et al., 2017), so far based on a single sample provided by the Laboratory of Historical Monuments (LRMH), to better constrain its use for artwork, eventually back beyond the mid-18th century.
The Materi-A-Net project is supported by the Franco-German FRAL program (ANR-21-FRAL-0014-01 and DFG 469987104) (https://materi-a-net.uni-koeln.de/en/the-project/)
Bresc-Bautier G. (2018) La sculpture en albâtre dans la France du XVIe siècle. Revue de l’Art, 200/2018-2, 37-45.
Jugie S., Leroux L., et al. (2024) L’albâtre et ses sources : incertitudes historiques et ambiguïtés de la documentation levées grâce aux analyses. Technè, 57, 49-59.
Kloppmann W., Leroux L., et al. (2017) Competing English, Spanish, and French alabaster trade in Europe over five centuries as evidenced by isotope fingerprinting. Proceedings of the National Academy of Sciences, 114, 11856–11860.
Lipińska A. (in press) Alabaster. Studies in Material Meaning(s), Studies in Art and Materiality, Leyde, Boston: Brill.
How to cite: Kloppmann, W., Dömling, U., Leroux, L., and Lipińska, A.: „Alabaster from Lagny“, myth or reality?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9880, https://doi.org/10.5194/egusphere-egu25-9880, 2025.
Measuring the ultrasonic pulse velocity of stone ashlars belonging to masonry structures provides useful indications for assessing the materials' strength and state of conservation, the need for their possible substitution, and the effectiveness of consolidating treatments. Ultrasound techniques as nondestructive tests preserve the integrity of masonry buildings that especially in Italy often have a cultural and historical-artistic value.
Several correlations linking ultrasonic velocity with the compressive strength of stone materials are available in the literature. These correlations are often developed in the laboratory using small-size samples, high measurement frequencies, and direct transmission measurement modes. In situ, it is often difficult to make measurements under such conditions due to the inaccessibility of both the surfaces of materials and the higher dimension of the elements to investigate. In addition, material surfaces are often affected by deterioration which causes problems in the transducer coupling with measurement surfaces. Furthermore, the use of coupling agents is usually forbidden in the case of artistic artifacts. The ultrasonic tomograph with pulse-echo technology (PE UT) overcomes such difficulties. Pulse-echo method introduces a stress pulse by a transmitter into an object at an accessible surface. The pulse propagates into the test object and is reflected by flaws or interfaces. The surface response caused by the arrival of reflected waves, or echoes, is monitored by receivers. Tomography gives visualization, either by cross-section or 3D images, of the interior structure of the object to find anomalies and determine the material physical properties. PE UT has an array of dry-point contact transducers (DPCT) that enable ultrasonic measurements on rough surfaces without coupling gel, reducing the measuring time and test invasiveness. PE UT employs transverse S-waves instead of longitudinal P-waves because they give more reliable results for degraded materials and in the presence of defects. In the literature, there are several studies in which tomographic images were used to detect the presence of defects in concrete and rock members. In these cases, a reference value of UPV is assumed. On the contrary, few studies use PE UT images to determine UPV on concrete or stone members. Thus, the appropriateness of this technique to assess UPV is still under research due to the lack of a sufficient number of published experimental studies.
In the present paper, the reliability of PE UT in determining the ultrasonic velocity of soft calcarenitic stone elements, known as Lecce stone, is investigated. The measurements are compared with those conducted with conventional transducers at different frequencies in direct and indirect modes. The measurements are also carried out considering the presence of water in the material, which strongly influences not only the ultrasonic measurements but also the strength of the material itself. Four levels of saturation from dry to fully saturated states are considered. The results of the experimental campaign evidence that PE UT is a reliable technique for UPV assessment, allowing rapid one-side measurements on surfaces in different conditions.
How to cite: Vasanelli, E., Di Gennaro, D., Sticchi, M., Blasi, G., and Aiello, M. A.: The use of ultrasonic pulse-echo tomography to assess UPV in soft calcarenitic stones, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20560, https://doi.org/10.5194/egusphere-egu25-20560, 2025.
Black crusts commonly form on historic buildings as a result of interactions between building materials and atmospheric pollutants. These crusts primarily consist of gypsum layers that develop on calcium-rich surfaces through sulfation processes, especially in urban environments with elevated atmospheric contaminants. Moreover, black crusts accumulate particulate matter, polyaromatic hydrocarbons, and heavy metals such as lead (Pb), largely originating from anthropogenic activities like vehicular emissions, coal combustion, and industrial operations. Acting as passive environmental samplers, these crusts offer valuable insight into urban pollution trends.
Although the water-soluble components of black crusts, such as Ca²⁺, Mg²⁺, Na⁺, and SO₄²⁻, have been extensively studied, the understanding of trace elements, particularly Pb, remains incomplete, especially regarding their behavior and mobility. This study aims to fill this gap by examining Pb distribution, availability, and interactions within black crusts and the underlying stone substrates. Samples collected from historical buildings in Antwerp were analyzed using a multi-technique approach. SEM-EDX was employed for initial chemical and morphological characterization, while LA-ICP-TOF-MS enabled the generation of high-resolution quantitative elemental distribution maps for major, minor, and trace elements. Depth-resolved analysis of Pb migration was further explored through portable LIBS, contributing to a deeper understanding of crust stratigraphy and pollutant dynamics.
Preliminary findings indicate that Pb is predominantly concentrated in the outermost layers of the black crust. Given the crust’s primary composition of gypsum, a sulfate mineral, it is hypothesized that Pb is sequestered as lead sulfates, contributing to its immobilization within the crust. However, this contrasts with existing literature, which highlights Pb’s stronger affinity for carbonate phases, suggesting a tendency for it to migrate into carbonate layers and potentially into the underlying stone substrate. The confinement of Pb within the crust deviates from expected behavior, raising important questions about its speciation. Understanding the conditions under which Pb could become mobile is crucial, with factors such as kinetic limitations, local pH variations, and environmental conditions like humidity and wet-dry cycles likely influencing its migration.
This research investigates the behavior of Pb within black crusts, aiming to advance the conservation of historic buildings while addressing the public health risks associated with urban lead exposure. By examining the factors influencing Pb mobility, the study seeks to inform the development of targeted mitigation strategies for lead contamination. The expected outcomes will not only contribute to the long-term preservation of cultural heritage but also enhance urban environmental safety, providing critical insights that bridge the fields of heritage conservation and public health.
How to cite: Deboli, S., Baele, J.-M., Bonazza, A., Van Acker, T., Vanhaecke, F., Wilhelm, K., and De Kock, T.: Lead Dynamics in Black Crusts: Elemental Distribution and Mobility Analysis in Lede Stone from Antwerp, Belgium, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8233, https://doi.org/10.5194/egusphere-egu25-8233, 2025.
Moisture has an important and essential role in the transportation of salts in masonry structures, therefore understanding the changes in moisture content provides valuable insights into the diagnostics of historic buildings, namely allowing the prediction of salt weathering. In this study, the thick walls of a fortress were studied. The Citadella is a landmark historic building in Budapest, that was built from Miocene porous limestone in the middle of the 19th century. Besides external cladding with porous limestone, the cores of the walls also contain volcanic tuffs. The walls are high (12-16 m) and their thickness is more than 1.5 m, which makes it difficult to record the moisture distribution. The sources of water are partly linked to direct precipitation on the wall surface or from capillary rise from pavement surfaces and from the soil. To assess the moisture distribution and salt content both on-site and laboratory analyses were performed during the dry summer period and wet autumn period. Not only the wall surfaces but also the subsurface zones and wall interiors were studied. Dry drillings were made to assess the in-depth moisture profile and salt content. Using an on-site moisture test it was possible to identify the moist and water-saturated zones of the ashlars and renders. Salt content and composition were measured on drilled dust samples and small samples obtained from the wall surface. Optical microscopy, XRF and XRD and Thermogravimetric analyses allowed the identification of salts. According to laboratory tests, the major salts responsible for the damage of external walls are gypsum, halite and hygroscopic nitric salts. The salt distribution within the depth shows seasonal variations. It was possible to detect the moisture distribution and salt content changes in depth and along vertical profiles. The results of the current research can be used to understand the moisture and salt distribution in thick natural stone walls and help in the diagnostics of historic structures and evaluate the salt weathering processes under various climate conditions.
How to cite: Kis, A. and Török, Á.: Seasonal changes of moisture and salt content of historic porous limestone walls; obtained form surface measurements and depth profiles, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9492, https://doi.org/10.5194/egusphere-egu25-9492, 2025.
The site of Mnajdra, one of the UNESCO-listed Megalithic Temples of Malta (https://whc.unesco.org/en/list/132) dating back to 3600 - 2400 BC, is located on the southern coast of the Maltese archipelago. This site, along with two other similar sites, was sheltered in 2009 with reversible, open-sided shelters, with the aim of mitigating the critical impact of the aggressive marine environment on the conservation of the limestone megaliths. Environmental conditions such as rain, wind, salt damage and direct insolation - triggering thermoclastism (thermal stress)- were identified as a key factor contributing to the progressive stone weathering and are currently being monitored by a multidisciplinary study.
This abstract will focus on understanding the impact of these protective, open-sided shelters on the temperature variations of the Mnajdra’s façade, with particular attention to diurnal and seasonal fluctuations, comparing to data available from the pre-sheltering period. Other studied environmental factors will not be addressed here.
The Mnajdra complex is widely recognized for its astronomical alignment, with the main (eastern) façade oriented to mark the equinoxes, solstices, and other solar events. In order to retain the association of the Temples with these alignments and to continue to observe these events, the shelters were designed to remain more open on the eastern side. As a result, surface temperature variations are currently monitored on the eastern façade, where direct sunlight could cause significant temperature fluctuations with possible subsequent deterioration effects such as microcracks formation and progressive material weakening.
Thermal imaging data was thus collected across two seasons - autumn (9th October 2023) and summer (19th June 2024) at 10-minute intervals during morning hours to identify trends of the fluctuations.
Results from these two campaigns revealed significant surface temperature fluctuations in autumn and lower variations in summer. Surface temperature gradients were observed, with a more intense gradient in autumn (from 27,8°C at 7.50 am to over 35°C at 8.50am), and less intense fluctuation in summer (from 27,3°C at 6.50am to 30,4°C at 7.50am). In both seasons, hotspots were identified particularly in areas of different megaliths (of the same stone type) where prolonged exposure (approximately 1h) to direct solar radiation occurred.
Taking into account the difference in air temperature recorded during the acquisition (19-25°C in October and 26-32°C in June) this difference can possibly be attributed to the inclination of the sun. The more significant surface temperature fluctuations observed in autumn are likely attributed to the angle of solar incidence at that time. The sun reaches the studied megaliths more directly in autumn and less directly in the summer solstice, resulting in greater variations in surface temperature.
This study forms part of a broader multidisciplinary project integrating non-invasive analytical techniques and environmental parameter modelling to evaluate the efficacy of sheltering systems. All the findings will provide scientific data to inform conservation strategies also aiming at mitigating the progressive weathering on these unique heritage sites, and ensuring their long-term preservation sites also in projection of increasing challenges due to the impacts of climate change.
How to cite: Faieta, R., Cassar, J., Valantinavičius, M., and Micallef, D.: Understanding some of the effects of shelter design on deterioration at the Mnajdra Megalithic Temples of Malta, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18921, https://doi.org/10.5194/egusphere-egu25-18921, 2025.
Cities are increasingly implementing nature-based solutions (NbS) to mitigate current climate stressors in urban environments, e.g. elevated temperatures and air pollutions levels. Among NbS, ground-based green façades are well-known for their ability to cover a large surface area of vegetation while using minimal ground space. This green initiative consists of climbing plants growing along a vertical surface by either attaching themselves to the surface or using a climbing aid.
Despite the proven benefits of green façades, historic buildings, crucial components of urban environments, are often neglected in urban mitigation strategies. Concerns about potential adverse effects of greening on materials durability and structural integrity, which is currently poorly understood, have limited their implementation on historic buildings. Our research aims to understand the impact of green façades on the degradation processes of historic building materials to unlock the co-benefits of greening built heritage and to explore the potential of green façades as a preventive conservation method.
To achieve this, we analyse the interaction of green initiatives and stone-built heritage in both outdoor and controlled environments. Case studies conducted in the historic city centre of Antwerp (Belgium) over the past two years provided valuable insights on how green façades have an impact on the local microclimate. Monitoring a wide range of environmental parameters, relevant for common degradation processes of built heritage, e.g. surface and air temperature, solar irradiation, moisture content, amount of wind-driven rain and relative humidity, enables an understanding of the mechanisms of green façades responsible for changes in the local microclimate and identifies the key extrinsic and intrinsic factors affecting the effectiveness of this greenery.
Our findings highlight the potential of green façades to reduce the risk of common degradation processes affecting built heritage. Green façades significantly reduces solar irradiation and moisture accumulation on wall surfaces, thereby lowering the risk of biodeterioration. It also lowers the maximum surface temperatures by providing shade and tempers the relative humidity fluctuations. This buffering effect reduces the likelihood of salt crystallisation, most common during summer. In winter, evergreen vegetation enhances resistance to freeze-thaw cycles by maintaining higher minimum surface temperatures through thermal blanketing and reducing moisture accumulation on wall surfaces.
This research provides valuable insights into the potential of green façades as a sustainable and preventive conservation method for stone-built heritage. By buffering environmental conditions at the wall surface, green façades can unlock co-benefits: improving urban environments while enhancing the durability of historic building materials. A deeper understanding of the behaviour of green façades on the degradation of historic building materials can support their implementation in urban environments, ensuring that stone-built heritage becomes more resilient to current and future climate challenges.
How to cite: De Groeve, M., Kale, E., Orr, S. A., and De Kock, T.: Implications of green façades on historic building materials, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15240, https://doi.org/10.5194/egusphere-egu25-15240, 2025.
Daylight is crucial for providing visual comfort, supporting well-being, and creating an energy-efficient environment. However, its integration into historical building conservation remains a vital yet underexplored area, requiring a delicate balance between improving occupant comfort and preserving the historical significance of these buildings.
This research investigates how daylight use is addressed in conservation policies and regulations within Belgium, with a focus on the Flanders region. The study employs a mixed-method approach, combining interviews with professionals in architecture, conservation, and built heritage with a comprehensive review of existing national, regional, and local regulations. These methods aim to evaluate the adequacy of current policies and explore opportunities for improvement.
Key questions addressed include: Which regulations and guidelines govern daylight considerations in restoration efforts? What are the most frequently altered building elements during restoration, and how does daylight integration factor into these changes? Additionally, the study probes the balance between preserving historical authenticity and adapting buildings for contemporary use, assessing whether local policies adequately support this equilibrium.
Findings reveal that while daylight optimization is increasingly recognized as essential for improving occupant comfort, energy efficiency, and the functionality of re-functioned historical buildings, its integration into conservation policies requires greater emphasis. The research highlights the need for interdisciplinary collaboration, such as architects and heritage conservationists working with environmental scientists to design innovative daylighting systems, alongside the development of more comprehensive daylight guidelines aligned with the unique requirements of historical buildings.
By exploring potential improvements to existing policies, this study aims to contribute to a more holistic approach to the restoration of historical buildings, ensuring that they remain both culturally significant and sustainably functional in modern contexts.
How to cite: Sönmez, N., Cılasun Kunduracı, A., and Erkan, Y.: Exploring Daylight Optimization Policies in the Conservation and Restoration of Historical Buildings in Belgium, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13034, https://doi.org/10.5194/egusphere-egu25-13034, 2025.
Short- and long-term variability in indoor microclimate conditions within conservation spaces (museums, galleries, archives, and libraries) can exacerbate the risk of deterioration of cultural materials. Active microclimate control systems are often installed to stabilize thermo-hygrometric conditions, conversely, massive buildings with thick walls are less affected by outdoor conditions due to their high thermal inertia. Historic reinforced concrete structures, like bunkers and fortifications, are often windowless, further providing stable microclimate and protecting sensitive materials from photodegradation. World War II (WWII) bunkers often labeled as “dark” or “painful heritage”, were initially perceived only as symbols of war and occupation, leading to neglect and material deterioration over time. However, the impossibility of their demolition gradually encouraged interest towards their reuse, raising awareness of their social, historical, and economic potential. This contribution provides a comprehensive microclimate analysis to support management strategies in a unique case study: the NTNU (Norwegian University of Science and Technology) library for cellulose-based materials, hosted within “Dora I” WWII bunker in Trondheim, Norway (63.43° N 10.40° E). The archive spans 3700 m2 and contains around 5200 m3 of collections, including ancient volumes, journals, newspapers, and pictures. “Dora I”, a massive reinforced concrete German submarine and terrestrial fortification with 3.5 m-thick walls, covers a total area of approximately 16,000 m². 10 thermo-hygrometers compliant with European standards were installed, ensuring representativeness of indoor conditions across two floors. Time series of air temperature (T) and relative humidity (RH) are significantly longer (7 years, since 2018) than most studies in the literature, and are continuous and complete with minimal number of missing values. Statistical approaches from climatology are applied to analyse T-RH data, decomposing time series into short-term (daily/noise) and long-term (seasonal) variability (extracted by sinusoidal fits) to provide insights into indoor climate dynamics. A comprehensive conservation risk assessment, based on dose-response functions, evaluated biological and chemical threats to archival materials using both raw and filtered (i.e., “clean”) microclimate data. This approach allows to examine how anthropogenic factors (e.g., access and archival management) in the noisy signal may exacerbate climate-induced conservation risks. The findings demonstrate the exceptional features of this massive building, where peak summer temperatures occur indoors 2 to 2.5 months later than outdoors, depending on sensor location. The study estimates no biological risks for cellulose materials from humidity-dependent insects or mould growth, with temperature-dependent insect degradation that remains a threat, particularly from June to December (although it has decreased over time). Chemical degradation risks, confirmed by three indicators, remains significant from July to October. This is evident when considering raw microclimate data, which reveals slight but still significant variations in risky days compared to "clean" data, suggesting a potential influence of human activities related to archival management. In conclusion, the findings underscore the benefits of massive structures in preserving vulnerable materials and a useful methodological approach in combining raw and filtered microclimate data to assess conservation risks. Analysing noise signal may inform conservators about the impact of their management practices, offering a useful framework for similar archival contexts worldwide.
How to cite: Boccacci, G., Frasca, F., Bertolin, C., Dahlin Saeter, T., Lund, E., and Siani, A. M.: Climate-induced Risk Assessment of Library Collections within Dora I WWII Bunker in Trondheim, Norway, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18457, https://doi.org/10.5194/egusphere-egu25-18457, 2025.
The lithological nature of the bedrock helps explain this differential erosion, the position of the station being on a loose area while a few hundred meters further south, the construction on the base of the Pointe-aux-Oies would have allowed the building to be protected from erosion.
How to cite: Schmitt, F. G., Gaullier, V., Blaise, E., and Cohen, O.: The fight against shoreline erosion along the coast of the second marine station of Wimereux (France), 1899-1942, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8054, https://doi.org/10.5194/egusphere-egu25-8054, 2025.
Recognizing the inestimable value of the UNESCO World Cultural Heritage Sites for future generations, it is necessary to be aware of their vulnerability to multi-risks in the context of global climate change and the growing interest and engagement of citizens and stakeholders.
Romania is home to nine categories of cultural heritage sites (CHSs) – the Horezu Monastery, the Churches of Moldavia, the Villages with Fortified Churches in Transylvania, the Dacian Fortresses of the Orăștie Mountains, the Wooden Churches of Maramureş, the Historic Centre of Sighişoara, the Roșia Montană Mining Landscape, the Brâncuși Monumental Ensemble of Târgu Jiu, and the Frontiers of the Roman Empire – Dacia.
This work has been partially developed in the frame of two projects: 10101/2024-UB SPAH, funded by the University of Bucharest, which emphasizes sustainable and participatory activities in heritage-aware communities facing geographical risks, and 395080/2024 GeoAlliance, titled “Driving Sustainable Urban Futures: A Romanian-Norwegian Innovation Geophysical Alliance for Green Transition and SMART City Development”. Supported by the EEA and Norway Grants, the latest project provided geophysical data for representative sampling urban of cultural heritage sites, underscoring the significant role that geophysics play in enhancing urban resilience. Results were integrated within a multi-criteria analysis (MCA) to assess the vulnerability of CHSs in Romania to both natural and man-made hazards. To apply the multicriteria analysis of CHSs vulnerability, a GIS database was developed with both natural and human-induced processes such as earthquakes, landslides, floods, that threaten the cultural heritage proprieties, being identified, mapped and ranked. This was followed by mapping the multi-hazard susceptibility features across the nine categories of the UNESCO World CHSs. The next step involved inventorying the specific attributes of each cultural heritage site that contribute to their vulnerability to various hazards and impact their resilience. The vulnerability assessment considered several intrinsic factors that can increase exposure to hazards. Key factors include the age and the height of the structure, the elevation and the level of insulation, the used construction materials, and foundation depth. Additionally, the effectiveness of modern infrastructure, especially the underground water pipes and sewage performance, along with shallow hydrogeological and geophysical induced changes, significantly influences their risk. Other important considerations included visitor numbers and the degree of degradation of the construction, as well as ongoing consolidation and renovation efforts.
The findings from multicriteria analysis revealed the most susceptible cultural heritage sites to both natural and human-induced hazards. The paper emphasizes that although many heritage sites are highly exposed to multiple hazards, some of these sites have lower vulnerability despite being susceptible to these threats. Additionally, certain hazard processes that initially seem harmless to the CHSs are long-term damage. The results of the present work can serve as a valuable resource for site managers, enabling them to better understand where the vulnerabilities of their managed site reside and to intervene with higher efficiency in day-to-day monitoring and maintenance. Additionally, the insights can assist central and local authorities in comprehending financial requirements and allocating the necessary budget for protection and management efforts in order to strengthen CHSs protection.
How to cite: Popovici, D., Andra-Toparceanu, A., Chitea, F., Armaș, I., Ovreiu, A. B., Malvica, S., and Carboni, D.: Assessment of UNESCO Cultural Heritage Sites Vulnerability through Multicriteria Analysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19597, https://doi.org/10.5194/egusphere-egu25-19597, 2025.
Marine geology is a relatively young discipline compared to the research conducted on land. In France, while the first draft of a geological map dates back to the 18th century (Guettard, 1746), it wasn't until 1980 that marine data on the metropolitan continental margins were integrated into the geological map at a 1/1,500,000 scale, published by the BRGM. Jean-Étienne Guettard, a physician, botanist, and mineralogist, and a friend of Lavoisier, already had the remarkable intuition of a continuity in geological formations across the English Channel. In 1917, Stanilas Meunier, in his "Geological History of the Sea," boldly claimed that the science of marine geology had French origins.
For a long time, the progress of marine geology was constrained by the barrier of the water column. Therefore, initial information about fossil seas came from land-based studies. In Northern France, particularly along the Boulonnais coast, pioneering work was carried out by Pierre Pruvost (1921, 1924) and Auguste-Pierre Dutertre, the latter writing in 1925 a geological report on Pointe aux Oies and the vicinity of the Wimereux Zoological Station in the Glanures Biologiques, published on the occasion of the Station’s fiftieth anniversary (1874-1924).
Louis Dangeard, one of the great pioneers of French marine geology, was the first in the world to publish a thesis in 1928 on a submarine basin, specifically that of the English Channel, after spending 7 consecutive years (1922-1928) aboard the prestigious research vessel “Pourquoi pas ?” under Captain Jean Charcot. Subsequently, in 1933, he succeeded in forming a team of researchers and students to establish the Marine Geology Center of Caen. In France, the first sheets of the sedimentological underwater map of the Atlantic continental shelf of France at a 1/100,000 scale were published in 1968 by the National Geographic Institute, with a remarkable contribution from Louis Dangeard’s former students: Jacques Bourcart and André Guilcher, along with Gilbert Boillot, Pierre Hommeril, Félix Hinschberger, Pierre Giresse, and Claude Larsonneur, working on state thesis topics focusing on the English Channel.
Subsequent work would be closely tied to technological advancements in marine tools, particularly geophysics, after the first oceanographic expeditions of the N/O Challenger (1872-1877). Using archives and historical sources, we trace here the evolution of marine geological cartography, a brief history of oceanographic vessels, and the exploration tools that gradually shaped the tectono-sedimentary understanding of the English Channel.
How to cite: Gaullier, V.: Birth and Evolution of Marine Geological Cartography: Contribution to the Tectono-Sedimentary Understanding of the English Channel, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15133, https://doi.org/10.5194/egusphere-egu25-15133, 2025.
Integrating vertical greening systems (VGS) into historic buildings presents both advantages and challenges related to heritage conservation and urban sustainability. VGS contribute environmental benefits, such as reducing surface temperatures, improving air quality, and supporting biodiversity. However, their implementation raises concerns about potential risks to architectural integrity and cultural heritage.
This study explores expert perspectives on the implementation of VGS in historic buildings, focusing on the environmental, cultural, social, economic, legal, and technical aspects. Using a mixed-methods approach, the research combines insights from a literature review with survey data gathered from experts in vertical greening and heritage conservation. Both open-ended and closed-ended responses were analyzed to identify variations in expert opinions.
The findings reveal a general recognition of the environmental benefits of VGS; however, significant technical and cultural concerns present obstacles to widespread adoption. The results emphasize the need for increased awareness and structured information for stakeholders to promote a balanced approach that maximizes the advantages of VGS while addressing the challenges associated with historic architecture.
How to cite: Kale, E., De Groeve, M., Erkan, Y., and De Kock, T.: Expert Insights on Integrating Vertical Greening Systems into Historic Buildings: Survey Findings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9102, https://doi.org/10.5194/egusphere-egu25-9102, 2025.
Advances in the accessibility of surveying and geoscience tools and developments in computer science have led to significant growth and rapid developments in the efficiency and accuracy of heritage documentation practices from objects to entire buildings and complexes. Modern cultural heritage research relies heavily on producing accurate 3D models using digital documentation methods such as photogrammetry and laser scanning. Innovative approaches to 3D documentation through digital photogrammetry and laser scanning provide the opportunity to create digital twins of real cultural heritage monuments. For these digital twins to be relatable to the real world for quantitative analysis, they must be scaled and oriented in some way. The most common method for accurately scaling 3D models is through the use of markers. Markers ensure accurate spatial measurements by linking coordinates in the model to real-world coordinates. These markers help in image orientation, calibration, and 3D reconstruction. Despite their common use, currently, there is no set of designed markers that can be universally used across various modeling methods and software. The present investigation aims to identify different types of markers used for commercial and research purposes, comparing and contrasting their type, accuracy, and suitability for specific applications. Based on an evaluation of existing software solutions and indicators through laboratory tests, the qualities of markers will be analyzed and evaluated to facilitate precise 3D modeling and improve the reliability of data collected through photogrammetry and laser scanning. The effectiveness of markers will be analyzed through comparative studies investigating how different configurations and types of markers affect the overall accuracy and effectiveness of reconstructed 3D models of photographed objects. The findings are intended to provide insight into best practices for selecting and implementing markers in archaeological surveys, contributing to more accurate and reliable results from modeling, creating newly developed innovative markers, and allowing broader applicability for precise 3D modeling of photographed national cultural heritage sites.
Acknowledgments: The authors would like to thank the Bulgarian National Science Fund for funding the research under the project "An integral approach in creating digital twins of archeological immovable monuments using innovative technologies", contract КP-06-Н82/1 - 06.12.2024.
How to cite: Pashova, L., Lirkov, I., Raykovska, M., Petkov, N., Georgiev, P., Jones, K., Kabadzhova, H., Evtimov, G., Vasilev, G., Harizanov, S., and Borisov, M.: Comparative analysis of digital markers in photogrammetry and laser scanning for documentation of archeological immovable monuments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16284, https://doi.org/10.5194/egusphere-egu25-16284, 2025.
The integrated studies within the field of non-invasive diagnostics for the characterization of the state of conservation of stone building materials of monuments have the common target to meet the current and future needs of society in the field of cultural heritage. The conservation of the built heritage requires many interventions aimed at analyzing the state of health of the monuments, their preventive preservation, reconstruction, and restoration. All actions and diagnostic analyses should respect the historical significance of the investigated monuments and the physical properties of the materials that make up the cultural heritage structures. In this context, the use of non-invasive diagnostic techniques of various nature (e.g. terrestrial laser scanner (TLS), digital photogrammetry, acoustic, electrical) plays a role of fundamental importance both in the preventive preservation and in the monitoring of monumental structures over time. In fact, the use of such techniques is also particularly effective in controlling the effectiveness of restoration interventions.
In this study we have examined different architectural elements (walls and semi-columns) of the Basilica of San Saturnino relevant monument in the historical centre of the town of Cagliari (Italy). The analysis has been carried out by different geomatic (TLS and digital photogrammetry) and geophysical (acoustics and electrical) techniques. The combined application of digital photogrammetry and terrestrial laser scanning can provide high-resolution 3D models calibrated and textured with both reflectance and natural colours useful for evaluating the state of conservation of surface materials and for rationally planning further geophysical analyses, particularly the acoustic ones carried out with tomographic methods. In this study the acoustic techniques applied in the ultrasonic range have been used essentially in two modes, namely: surface and transmission. The obtained 2D models adequately describe the longitudinal velocity distribution both on the shallow parts of the investigated old walls and on the internal section of different architectural elements (semi-columns) showing the influence of the variation of intrinsic rock properties on the ultrasonic longitudinal wave propagation. The electrical resistivity data acquired on the surface of the old walls have allowed to depict the resistivity distribution on the wall surface. Electrical resistivity is a physical property of a rock that characterizes its conductive properties. For porous media such as the building carbonate rocks under study, the electrical resistivity depends on many physical properties (i.e., internal structure, water content, fluid composition and porosity) and together with the elastic properties can be useful to interpret the various properties of the investigated materials and their conservation state. In conclusion, the non-invasive techniques applied in this study can effectively aid the restoration of the building materials at Basilica di San Saturnino, Cagliari, Italy. This study confirms how each technique gave a range of different information to the restorers, and the interventions that can be undertaken in light of the acquired knowledge of the investigated monument.
Acknowledgements: The authors would like to thank the Ministero della Cultura- DIREZIONE GENERALE MUSEI - DIREZIONE REGIONALE MUSEI SARDEGNA (ITALY) for their kind permission to work on the San Saturnino Basilica (Cagliari – Italy).
How to cite: Casula, G., Fais, S., Bianchi, M. G., and Ligas, P.: A multi-analytical approach to assess potential damaged areas on the building materials of monumental structures., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4351, https://doi.org/10.5194/egusphere-egu25-4351, 2025.
One of the most visited historical sites of Budapest is the Heroes’ Square, where a 36 m high Corinthian-style stone column forms part of the Millennium Monument. On the top of the column, a bronze statue depicting Archangel Gabriel is visible. The monument was inaugurated in 1901. The stone column consists of ring-shaped limestone segments (drums). In the conical shape, the drums have a diameter of 2.25 at the lower part of the column, which reduces to 1.9 m at the top. Each drum is 0.5 m high. The condition of the stone column has aggravated in the past 120 years and the current research provides an overview of the actual condition of the stone elements and gives some hints on the preservation of the bronze statue. Tests included the on-site identification of major lithotypes, and testing surface strength and weathering grade using a Schmidt hammer. The moisture distribution was detected using a portable moisture meter. Small samples were collected for laboratory analyses and oriented samples were taken representing the north, east, south and west directions, with different exposure to sun and precipitation, representing different micro-climates. Textural analyses of samples were made by using optical microscopy and SEM-BSE, while mineralogical composition and elemental analyses were performed using XRF and thermogravimetric analyses. The prevailing lithotype is Pleistocene travertine with some textural varieties. The most common weathering forms are black crusts, dissolution features, and green staining of the stone surface from dissolved bronze. The composition of weathering crusts differs from the orientation, namely wind and rain-exposed parts have a different composition than the sheltered ones. The stability of the column was also analyzed. During structural analyses, a minor amount of cracks were also recognized. Loss of renders and dissolution of the stone surface can also cause problems. The study provides an example of integrated research of material properties and structural stability of historic stone structures.
How to cite: Török, Á. and Kis, A.: Diagnostics and preparation of restoration works of a 36 m high stone column holding a giant bronze statue, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10376, https://doi.org/10.5194/egusphere-egu25-10376, 2025.
One of the most critical challenges for preserving and protecting historical built heritage in coastal regions is the comprehension of the interaction between building materials and seawater or sea spray and its effects in time. This contribution addresses the forms and dynamics of sea salt weathering by considering as case study Mykonos Castle in Greece, built from the 13th century and now surviving only in its towers, churches, and stone walls, being just a few meters away from the shore or even underwater. The fieldwork and preliminary laboratory activities were arranged for investigating the petrographic characteristics and decay patterns of the main building stones (gneisses, marbles, granitoids, etc.), their in-pore salt content constrained by orientation, height, and distance from the sea, and rate and amount of their surface erosion monitored on site. The findings are expected to help assessing the vulnerability of cultural heritage in coastal regions due to changing environmental stresses, also in view of climate change.
Acknowledgements
This study is carried out within the project THETIDA, which has received funding from the European Union's Horizon Europe scheme under the program Culture, Creativity and Inclusive Society (grant agreement no. 101095253).
How to cite: Germinario, L. and Mazzoli, C.: Salt weathering of coastal stone heritage in Mykonos, Greece, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2063, https://doi.org/10.5194/egusphere-egu25-2063, 2025.
Rock erodibility is an intrinsic property defined as the vulnerability of a rock to erosion (Martínez-Martínez et al., 2024; doi: 10.1201/9781003429234-177). Intuitively, erodibility is a key concept in cultural heritage conservation, especially in studies concerning the exposure of building materials to wind, rain, hail, and human activity. However, research on its implications for heritage conservation remains scarce.
Abrasion resistance of rocks is a property routinely measured in geomechanical laboratories and it offers a practical approach to assessing the erosion susceptibility of the material. Two standardized methods, the Böhme abrasion test and the Wide Wheel Abrasion test, are widely used to evaluate abrasion resistance in dimension stones. However, these methods require both large and numerous samples, rendering them unsuitable for cultural heritage studies, where sampling is severely limited. To overcome this limitation, a modified version of the Böhme abrasion test is proposed. This adaption uses a plate grinding machine commonly employed for preparing rock thin sections, making the procedure widely accessible in geoscience laboratories.
The standardized Böhme Abrasion test requires cubic samples of 71 mm size, place on a grinding plate and subjected to an abrasive load of 294N for 16 cycles of 22 turns each. Wear is calculated from the loss in volume and weight. In contrast, the modified procedure uses smaller prismatic samples (20×30×30 mm) and a plate grinding machine operating at 30 cycles per minute under a load of 0.02 N/mm². Sample dimensions and weight are measured at the beginning of the test. Each sample is abraded for 15 minutes on two perpendicular surfaces, and the final dried weight is recorded (Martínez-Martínez et al., 2017; doi: 10.1016/j.buildenv.2017.05.034). Material loss is quantified as the modified Böhme Abrasion Loss (mBAL), calculated using the equation
mBAL = ΔV = Δm/ρb
where ΔV is the volume loss (in mm3); Δm is the mass difference (in g); and ρb is the bulk density of the rock.
This modified procedure was validated using a variety of commercial dimension stones, including limestones, marbles, travertines, tuffs, calcarenites, calcirrudites, sandstones, quartzites and slates. Results where compared to those obtained with the standardized Wide Wheel Abrasion test on the same rock types. A strong correlation (R2=0.87) was observed between the two methods, expressed by the equation
mBAL = 8.9 Tww – 86.5
where Tww the wear trace measured in the Wide Wheel Abrasion Test.
This modified approach offers a viable solution for assessing erosion susceptibility in heritage contexts, enabling reliable quantification with minimal material requirements. It offers a valuable tool for developing effective conservation strategies for cultural heritage.
This work was supported by grant numbers PID2020-116896RB-C21 and PID2020-116896RB-C22 funded by MCIN/AEI/ 10.13039/501100011033
How to cite: Martínez-Martínez, J., Berrezueta, E., Benavente, D., and Kóvacs, T.: Preliminary proposal for an experimental method to measure erosion susceptibility of heritage stones, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17798, https://doi.org/10.5194/egusphere-egu25-17798, 2025.
The present study investigated the relationship between the Salt Weathering Index (SSI) (Yu & Oguchi, 2010) and WAC, which is one of the methods used to evaluate the physical properties of stone, using various salt weathering experiments on building stones and artificial stones. The stone types studied were tuff (Oya stone, Towada stone, Ashino stone, Nikka stone, Tatsuyama stone), granite (Makabe stone), sandstone (Tago stone, Indian sandstone), porous rhyolite (Koga stone), and brick. Of these, 10 types of bricks, both homemade and commercial, were used. As a result, there was a rough correlation between SSI and WAC, and the multiple linear approximation had the highest coefficient of determination. The reason for the variation in the approximation formula is the difference in rock structure. In other words, for porous rhyolite and some bricks, which were probably fired at high temperatures, the WAC value was higher than the SSI value, whereas, for sandstone and dense tuff which were formed at low temperatures, the WAC value tended to be lower. In addition, the highest coefficient of determination between the rate of dry weight loss (DWL) and the SSI was obtained in the salt weathering experiment using a total immersion method with Na2SO4, MgSO4, and Na2CO3 solutions. This is probably because the MgSO4 solution has the highest viscosity and crystallization occurs in the deeper layers, which flake off on re-immersion. For Na2SO4, the coefficient of determination is high, except for the Tago sandstone. Although the reason for this is unclear, it is considered that the Na2SO4 precipitated dissolved before it had time to grow sufficiently. In the case of Na2CO3, the DWL is high in the Indian sandstone, but this is thought to be because the quartz that makes up the sandstone dissolved in the alkaline solution.
How to cite: Oguchi, C.: Salt Susceptibility Index for various building stones and their practical durability, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12344, https://doi.org/10.5194/egusphere-egu25-12344, 2025.
Natural Hydraulic Lime (NHL) binders are generally preferred to those cement-based in case of restoration works, thanks to their good compatibility with historical substrates. Moreover, they can be considered more sustainable in comparison to cement, being sintered at lower temperatures. Nonetheless, while having a good compatibility with historic substrates, their performance might need improvement in terms of strength values and strength development without sensibly affecting their stiffness.
To this purpose, the incorporation of Graphene Oxide (GO) was considered, due to the beneficial effects showed by studies on cementitious binders. This work presents the characterization of NHL pastes (i.e. without aggregates) prepared with a water-to-binder ratio of 0.5 and 3 different dosages of GO retrieved from literature about cement and concrete, namely 0.01%, 0.06% and 0.12% by weight of NHL dry powder.
The NHL powder and the reacted binder were characterized via X-ray Powder Diffraction (XRD) and Scanning Electron Microscopy (SEM). From a mechanical standpoint, indirect tensile and compressive strengths were tested at 28 and 84 days of age, while stiffness was assessed via Ultrasonic Pulse Velocity (UPV) at 7, 14 and 28 days of age.
Preliminary results showed a minor strength improvement, which was more apparent at 84 days of age, with no remarkable modification of the stiffness. Results also indicates that it might be worth testing possible greater dosages of GO.
How to cite: Garbin, E., Panizza, M., Dalconi, M. C., Nodari, L., Costinas, C., Baia, L., Coteţ, L. C., and Tomasin, P.: An assessment of GO addition to an NHL binder, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3685, https://doi.org/10.5194/egusphere-egu25-3685, 2025.
In many countries, construction, agriculture and livestock sectors produce and emit a large amount of waste and greenhouse gases, accelerating the climate change. For that, new trends and policies for waste management are required due to the high and constant demand for natural resources. The recent activities framed in the green economy are favouring the reuse and recycling of many waste products, in the so-called “Zero Waste” initiatives to reduce the carbon footprint, as well as to the reduction of associated energy expenditure. Among these waste products, those linked to animal by-products not intended for human consumption are usually incinerated for their elimination in Spain, contributing to the emission of CO2. Consequently, new initiatives are required to promote the reuse of this waste, such as in the development of more sustainable construction products. This paper presents the new results of the SoSCal Project, comparing sets of lime mortar with a proportion of cow hair of 0%, 0.5%, 1%, 2%, 5%, 10% and 12% in weight per kilo of mortar. Some of the advances achieved are that, regardless of the amount of hair added, no cracking process has been observed and the amount of water required can be reduced by 5%, so that extrapolation to larger production quantities would result in significant savings. Although it is necessary to carry out more tests since the workability is compromised, and therefore it will be important to find conditions according to the need for the applicability of the mortar. Another aspect is the increase in the resistance to crystallization of salts with respect to the mortar without fibres, although the durability has been greater in practically all cases, regardless of the quantity of fibres. The addition of hair has affected the thermal properties, specifically the heat transmissivity through the samples, showing a direct relationship between the percentage of added hair and this parameter. The maximum recorded temperatures differed by almost 8°C between the samples without fibres (0%) and those containing 12% of hair after one hour of heating, with the latter also cooling down much faster due to the higher hair content. Based on the results obtained, the addition of animal fibres is showing very positive results compared to the reference mortar. Thus, enhancing the properties of a traditional product, such as lime, compared to Portland cement will also have a very positive effect, since it could reduce the production of this type of cement by having other options, which would also imply reducing the emission of CO2 into the atmosphere. However, it is necessary to continue with the tests already started and to carry out other tests, especially mechanical and weathering durability tests to evaluate its performance.
Acknowledgements: This study was financially supported by the Research Project TED2021-132417A-I00 funded by MCIN/AEI /10.13039/501100011033 and by the European Union NextGenerationEU/ PRTR
How to cite: Molina-Piernas, E., Pacheco-Orellana, M. J., Martínez-López, J., Domínguez-Bella, S., and Sánchez-Bellón, Á.: Improving the sustainability of lime mortars by reusing cow hair, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12731, https://doi.org/10.5194/egusphere-egu25-12731, 2025.
In Roman Baetica and specifically in the city of Gades (Cádiz, Spain), studies about Roman mural paintings has been mainly approached from a traditional perspective, with specific exceptions where archaeometric studies have been carried out on this type of construction and decorative materials. During an archaeological intervention carried out in the Santa Bárbara car park in Cádiz between 2009 and 2012, several Roman mural paintings fragments from the levels of waste deposits were documented. The archaeological record has allowed the levels to be dated between the 1st century BC and the 1st century AD., thus this set of pictorial remains belongs to the Republican phase or to the initial stage of the Augustean period of Gades, a period with hardly any examples of pictorial representations from the early times in Baetica. Due to the number of fragments of Roman paintings with a great variety of colours, several analytical methodologies to know the composition, technique and quality of the paintings were carried out by means X-ray diffraction, X-ray fluorescence spectroscopy, Raman spectroscopy, FTIR, polarized optical microscope, scanning electron microscope, cathodoluminescence microscope and spectrophotometry. A representative set of 31 samples was chosen for this study. Some samples only show a single layer of paint on the mortar, but it is more frequent to find several overlapping layers. The colour palette presents: light and dark blue; bright, light and dark red; purple; light and dark yellow; light green and green; white, brown and lampblack. These colours were identify as egyptian blue, cinnabar, hematite, iron ochers, celadonite, calcite, black, and mixtures between them. On the other hand, the mortars characterization showed two types, the first one is the most numerous and were used as substrate for all identified colours, except for pure black. In fact, fragments that only presented the black pigment, sometimes with lines in white, have been identified on the intonaco layers with ceramic. This remains probably corresponded with a prominent Roman urban villa placed in the Eriteia island of Gades, confirming the importance that this city had within the Roman Empire.
Acknowledgements: This study was financially supported by the Research Project TED2021-132417A-I00 founded by MCIN/AEI /10.13039/501100011033 and by the European Union NextGenerationEU/PRTR, and the Research Project “La gestión de los residuos sólidos en Gades. Aproximación a la caracterización tipológica de los vertidos y su inserción en el entramado urbano de una ciudad costera” (CEIJ-006) Fundación CEiMAR.
How to cite: Domínguez-Bella, S., Lara Medina, M., Pascual Sanchez, M. A., and Molina-Piernas, E.: Archaeometrical characterization of the Roman wall paintings from Gades (Cádiz, Spain)., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20444, https://doi.org/10.5194/egusphere-egu25-20444, 2025.
Posters virtual: Thu, 1 May, 14:00–15:45 | vPoster spot 4
EGU25-13397 | ECS | Posters virtual | VPS17
The built material architectural cultural heritage tested by the Al Haouz earthquake: Case of the Koutoubia Mosque in the city of MarrakechThu, 01 May, 14:00–15:45 (CEST) | vP4.2
What is more frightening than an unexpected earthquake in the middle of the night for people and for buildings and especially heritage buildings whose response to the earthquake is unknown.
The country of Morocco, and more precisely the region of Al Haouz, more precisely the city of Marrakech named capital of culture of the Islamic world for the year 2024, by the Islamic World Educational, Scientific and Cultural Organization (ICESCO), experienced a serious earthquake of magnetitude M = 6.9 on September 8, 2023 at 22:11:2.2 UTC (23:11 Local), the most serious earthquake in the history of the country according to seismic stations.
The Koutoubia Mosque built in the 12th century was one monument among others that suffered this tremor.
In this article we will describe the location, the construction technique and the materials used in this monument and we will also go through in a non-exhaustive manner the damage caused by this earthquake on the Koutoubia Mosque whose architecture is part of Almohad art.
How to cite: Belhaj, S., Baba, K., Belhaj, O. E., and Nounah, A.: The built material architectural cultural heritage tested by the Al Haouz earthquake: Case of the Koutoubia Mosque in the city of Marrakech, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13397, https://doi.org/10.5194/egusphere-egu25-13397, 2025.
EGU25-21192 | Posters virtual | VPS17
An approach to develop suitable criteria for cob and adobe techniquesThu, 01 May, 14:00–15:45 (CEST) | vP4.3
The use of earth in the building industry offers the opportunity to reuse soil whiles meeting the challenges of circular economy through soil reuse and low embodied energy. However, the lack of standardized criteria for soil classification, suitability and a comprehensive understanding of the interactions between soil properties and construction techniques remain a significant barrier to widespread adoption. This study aims to propose criteria for evaluating and optimizing soil classification and suitability in earthen construction through experimental analyses. For this, the study will use three different soils, sampled from three different regions in France. Straw- fibred and non-fibred cylindrical specimen will be prepared in laboratory using the cob and adobe techniques. The prepared specimens will be dried at 40 °C and conditioned in a climatic chamber at 20 °C and 50 % relative humidity. The variation in dry densities, and Unconfined Compressive Strength (UCS) of the cob and adobe specimens will be observed. The impact of soil properties and implementation parameters such as water content, mineralogical composition (calcite and dolomite content) on these variations will be analyzed. To underline the contribution of these parameters, a principal component analysis (PCA) will be conducted on all the results to identify the most dominant factors affecting mainly the dry densities and soil strength. Future work will study the microstructure evolution in the specimens using the Brunauer – Emmett – Teller (BET) and the Mercury Intrusion Porosimetry (MIP) tests. The mechanical behaviour and microstructure evolution will be combined into developing new criteria for soil suitability considering the implementation process parameters and soil properties for earth construction.
How to cite: Ansaa-Asare, R. J., Das, G., Hamard, E., Razakamanantsoa, A., Duc, M., Cazacliu, B., and Verron, L.: An approach to develop suitable criteria for cob and adobe techniques, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21192, https://doi.org/10.5194/egusphere-egu25-21192, 2025.
