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Weiyang Palace, the royal palace of the Western Han Dynasty, is a part of the Silk Roads: the Routes Network of Chang'an-Tianshan Corridor on the World Heritage list. The south palace wall of Weiyang Palace is a well-preserved earthen heritage site within the palace, but it is undergoing continuous deterioration due to the influence of vegetation and external environmental factors. This study pioneers the integration of high-resolution three-dimensional LiDAR scanning with multi-source data analysis, including unprecedented on-site botanical surveys, to explore the subtle effects of different vegetation types on the structural integrity of the south palace wall. Through contour line analysis and facade grid analysis, we extracted the deterioration locations of typical sections of the earthen heritage sites. And we classified the overlying vegetation types on the wall using an object-oriented classification algorithm. Our findings reveal a complex interaction between vegetation and earthen structures: paper mulberry exhibits protective qualities against erosion, while Ziziphus jujuba significantly exacerbates structural vulnerabilities. The methodologies applied in this study for extracting deterioration at earthen heritage sites and integrating multi-source spatial data can serve as a technical application model for monitoring and analyzing the driving forces of earthen heritage sites along the entire Silk Road network, thereby better guiding the conservation of earthen heritage sites. [ABSTRACT FROM AUTHOR]

Abstract Weiyang Palace, the royal palace of the Western Han Dynasty, is a part of the Silk Roads: the Routes Network of Chang’an-Tianshan Corridor on the World Heritage list. The south palace wall of Weiyang Palace is a well-preserved earthen heritage site within the palace, but it is undergoing continuous deterioration due to the influence of vegetation and external environmental factors. This study pioneers the integration of high-resolution three-dimensional LiDAR scanning with multi-source data analysis, including unprecedented on-site botanical surveys, to explore the subtle effects of different vegetation types on the structural integrity of the south palace wall. Through contour line analysis and facade grid analysis, we extracted the deterioration locations of typical sections of the earthen heritage sites. And we classified the overlying vegetation types on the wall using an object-oriented classification algorithm. Our findings reveal a complex interaction between vegetation and earthen structures: paper mulberry exhibits protective qualities against erosion, while Ziziphus jujuba significantly exacerbates structural vulnerabilities. The methodologies applied in this study for extracting deterioration at earthen heritage sites and integrating multi-source spatial data can serve as a technical application model for monitoring and analyzing the driving forces of earthen heritage sites along the entire Silk Road network, thereby better guiding the conservation of earthen heritage sites.

Preservation strategies at earthen archaeological sites are challenging to develop and maintain in the long term. Environmental fluctuations, anthropogenic interference, and pedological composition are only a few factors that can impact deterioration pathways. Owing to these complexities, there will never be a one-size-fits-all strategy for preserving earthen sites. However, archaeological spoil—or backdirt—can be employed to mitigate many of these challenges. Utilizing illustrative case studies at the earthen sites of Çatalhöyük, Turkey, and Vésztő-Mágor, Hungary, the authors present the use of backdirt as a sustainable, structurally supportive, contextually sympathetic, and visually congruent material for earthen site conservation. Matters of authenticity, ethical mandates, and social benefits of its use are also considered, as are its limitations. [ABSTRACT FROM AUTHOR]

This paper shows the restoration work carried out on the mudbrick structures uncovered at the Iron Age (c. 1300-300 BC) site of Salūt, in central Oman. In the region, traditional earthen architecture represented the key building technique until modern times. The traditional concept of constant upkeep is arguably the only way of efficiently preserving ancient structures. However, different mud plaster compositions were tested which could provide a better aspect and a lower static load on the structures. The work strategy was meant to be sustainable from an economic, ecological, and sociological point of view, as it also aimed at documenting and hopefully reviving the traditional earthen architecture currently endangered by the disinterest of younger generations.

Despite its seismic activity, Chile has a large number of heritage buildings built with earth. Their conservation depends on elements such as roofing and foundations, but also on the quality of renders and finishing materials. This study seeks to identify and characterize the coating systems and materials used on the wall surfaces of earthen heritage structures in the Limarí valley, Chile, seeking to contribute to the dissemination, promotion, and preservation of these traditional renders. The case studies included are historic buildings in various Limarí valley villages. Render and plaster samples of earthen built heritage were taken for analysis from a diversity of wall structures (such as adobe, pandereta, or quincha) and finishing techniques. Despite differences, the conclusions of our fieldwork and sample observations and analysis allow us to identify effective, common coating systems and finishes.

Earthen heritage represents an important legacy regarding construction history and technological development, with a significant cultural value that must be preserved. According to UNESCO, around 10% of the World Heritage is built using earth, and 57% of these heritage structures are in danger. Although the interest regarding earthen heritage has grown in the last few years, there is still a significant lack of knowledge in terms of material characterization, especially from conservation science point-of-view. In particular, tests regarding water absorption are always difficult to perform with a material that changes completely when in contact with water. Indeed, due to the presence of clay particles, a normal capillarity test is almost impossible to perform. Moreover, water is responsible for a significant number of degradation phenomena often found in earthen heritage. As a result, there is an urgent need to develop suitable water repellent treatments and to evaluate their efficiency. For this reason, this study focuses on the contact sponge method to assess water absorption rates for adobe and for rammed earth specimens treated with three different water repellents — siloxane, linseed oil, and beeswax. Two sets of specimens were prepared and tested, showing that this method can represent an effective way to measure initial water absorption in earthen materials, and promising results from the tested water repellent treatments were found. [ABSTRACT FROM AUTHOR]

Abstract Earthen heritage constitutes 10% of sites on the World Heritage List and many of these sites are experiencing extensive deterioration caused by environmental forces, such as wind and rain. This study used a well-established test wall to investigate the impact of environmental conditions on the deterioration of earthen heritage at the remote and under-studied site of Suoyang Ancient City, Gansu Province, China, which is exhibiting widespread deterioration. Test walls have previously been used in earthen heritage research as they allow controlled experiments to be undertaken on complex, realistic structures without risking damage or loss of value to the historic material. This study used portable wind and rain erosion simulation devices to investigate experimentally (i) the comparative effect of wind, sediment-laden wind and wind-driven rain in causing deterioration to earthen heritage and (ii) how the incipient deterioration features produced by wind, sediment-laden wind and wind-driven rain on the test wall relate to the deterioration features recorded on the historic city walls. The test wall was subjected to low, medium and high intensities of clean wind, sediment-laden wind and wind-driven rain. The extent of deterioration produced was measured using repeat, high resolution laser scans before and after each test run. The deterioration features caused by each environmental force were notably different with clean wind removing the loose surface material, sediment-laden wind causing pitting and wind-driven rain causing incipient gullying. These incipient features compare well with more developed features seen on the historic walls. Wind-driven rain caused the greatest amount of deterioration while clean wind caused the least. However, as the frequency and duration of wind events at Suoyang is much greater than those of rain events, wind is likely to play an important role in the deterioration of earthen heritage over annual timescales. These findings show that conservation strategies at rammed earth sites like Suoyang need to address the impact of multiple environmental forces, such as clean wind, sediment laden wind and wind-driven rain.

Copyright of Loggia, Arquitectura & Restauración is the property of Universidad Politecnica de Valencia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The variable climatic and environmental conditions associated with dryland regions can cause rapid erosion to both natural and man‐made earthen structures. Whilst there is a long history of research into the evolution of erosional landforms such as yardangs, little research has investigated how dryland processes influence the erosion of built structures. Earthen heritage sites located in arid and semi‐arid environments experience rapid deterioration caused by exposure to environmental drivers such as wind and rain. Understanding how these environmental drivers interact with each other and cause deterioration to earthen material is vital for successful conservation strategies. To address this need, we present the Vegetation and Sediment TrAnsport model for Heritage Deterioration (ViSTA‐HD) that simulates the risk of polishing, pitting and slurry on earthen heritage in a spatially specific manner. A technical description of the model is provided, and sensitivity and validation tests are reported. The model is then used to simulate the risk of deterioration occurring over centennial timescales at a Suoyang Ancient City, located in semi‐arid northwest China. The modelled risk of deterioration is in good agreement with deterioration patterns found at Suoyang, with the risk of polishing predominantly occurring around the wall edges, areas at risk of pitting echoing the dune formation and the risk of slurry occurring in drape‐like patterns down the wall face. Consequently, ViSTA‐HD is a powerful and versatile model that can be used to help inform our understandings of long‐term interactions between dryland processes and deteriorative impact on earthen structures. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

This research investigates fundamental problems in object recognition in earthen heritage and addresses the possibility of an automatic crack detection method for rammed earth images. We propose and validate a straightforward support vector machine (SVM)-based bidirectional morphological approach to automatically generate crack and texture line maps through transforming a surface image into an intermediate representation. Rather than relying on the application of the eight connectivity rule to a combination of horizontal and vertical gradient to extract edges, we instruct an edge classifier in the form of a support vector machine from features computed on each direction separately. The model couples a bidirectional local gradient and geometrical characteristics. It constitutes of four elements: (1) bidirectional edge maps; (2) bidirectional equivalent connected component maps; (3) SVM-based classifier and (4) crack and architectural line feature map generation. Relevant details are discussed in each part. Finally, the efficiency of the proposed algorithm is verified in a set of simulations that is satisfactorily conforming to labeled data provided manually for surface images of earthen heritage. [ABSTRACT FROM AUTHOR]

Using earth as a construction material is an ancient technique that can be found around the world in monumental and vernacular architecture. Earthen heritage is also associated with maintenance techniques employing natural and local products still being used in some countries. Having those methods as a background, this paper proposes to adopt a green conservation strategy and a scientific approach, learning from traditional procedures to apply on earthen heritage. In the present research, three natural products -- arabic gum, linseed oil and beeswax -- were studied in terms of efficiency with adobe specimens, by means of non-destructive tests (colorimetry and water absorption). The obtained data shows promising results regarding the use of natural products as an alternative for earthen heritage protection. [ABSTRACT FROM AUTHOR]

Using earth as a construction material is an ancient technique that can be found around the world in monumental and vernacular architecture. Earthen heritage is also associated with maintenance techniques employing natural and local products still being used in some countries. Having those methods as a background, this paper proposes to adopt a green conservation strategy and a scientific approach, learning from traditional procedures to apply on earthen heritage. In the present research, three natural products - arabic gum, linseed oil and beeswax - were studied in terms of efficiency with adobe specimens, by means of non-destructive tests (colorimetry and water absorption). The obtained data shows promising results regarding the use of natural products as an alternative for earthen heritage protection. [ABSTRACT FROM AUTHOR]

This research investigates fundamental problems in object recognition in earthen heritage and addresses the possibility of an automatic crack detection method for rammed earth images. We propose and validate a straightforward support vector machine (SVM)-based bidirectional morphological approach to automatically generate crack and texture line maps through transforming a surface image into an intermediate representation. Rather than relying on the application of the eight connectivity rule to a combination of horizontal and vertical gradient to extract edges, we instruct an edge classifier in the form of a support vector machine from features computed on each direction separately. The model couples a bidirectional local gradient and geometrical characteristics. It constitutes of four elements: (1) bidirectional edge maps; (2) bidirectional equivalent connected component maps; (3) SVM-based classifier and (4) crack and architectural line feature map generation. Relevant details are discussed in each part. Finally, the efficiency of the proposed algorithm is verified in a set of simulations that is satisfactorily conforming to labeled data provided manually for surface images of earthen heritage.

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

New Gourna Village, which is located inside one of the World Heritage Sites in Egypt, has never been recognized as an element contributing to the site’s Outstanding Universal Value. The recognition of the village as a contributing element is reliant on the successful assessment of its authenticity and integrity. Responding to the dramatically declining integrity of the village, the World Heritage Centre has carried out an architectural study to guide the potential conservation works in the property. The study has recommended that a group of objectives and two approaches to the conservation of the village should be adopted. One of these two approaches has been concerned with the conservation of the village according to the architect’s original intentions and principles. The previous approach can be called the principles-based approach. The main aim of this study was to examine the agreement of the World Heritage Centre’s objectives and their proposed principles-based approach to the conservation of the village with the aim to improve its chance in meeting the conditions of authenticity and integrity. The study approached the previous aim by assessing, by means of a proposed methodology; the level of significance, authenticity and integrity of the property. Based on the previous assessment, a list of conservation interventions was proposed to improve the property’s chance in meeting the conditions of authenticity and integrity. Finally, the World Heritage Centre’s recommended approaches and objectives were examined against the previous proposed conservation interventions. The findings indicated the possibility to adopt the principles-based approach to the conservation of New Gourna Village, as well as the other World Heritage Centre’s objectives, without limiting the property’s chance in meeting the conditions of authenticity and integrity. The study recommends to carry out further studies that are concerned with the identification of the architect’s philosophy and architectural principles that should be the key reference of all the potential conservation interventions in the village.

The authenticity of earthen heritage has long been a challenge to the trials of the under-represented States Parties, to the World Heritage Convention, to identify properties for listing on their Tentative Lists, of potential World Heritage Sites. Many under-represented States Parties and regions, such as Africa and the Arab States, retain a large number of properties representing earthen heritage, yet none of them has been inscribed on the World Heritage List. For such a pattern of cultural heritage to qualify for the World Heritage Site status, nominated properties should enjoy an Outstanding Universal Value and should also meet the conditions of authenticity and integrity. Due to the fragility of its building material, earthen heritage has always been the subject of continuous maintenance works to its material. Consequently, an impression that the material authenticity of such cultural heritage is questionable has evolved. The main purpose of this study was to discuss such perceptions in further depth. The study also aimed at evaluating the contribution of the “materials and substance” attribute versus the contribution of the other attributes of authenticity, toward the evaluation of the authenticity of earthen heritage. The study approached these objectives by evaluating by means of a proposed methodology the authenticity of one case study, which is Ramses Wissa Wassef Art Centre, in Egypt. The adopted evaluation methodology was developed based on the Nara Document’s notion of authenticity. The findings indicated the significant contribution of the non-material attributes, vis-à-vis the contribution of the “materials and substance” attribute, toward the authenticity of the examined property. The results suggest the need to broaden the narrow perception that reduces the authenticity of earthen heritage to its material aspects, so as to embrace all the other non-material attributes of authenticity.

The Site of Yar City (formerly known as the ancient city of Jiaohe) is regarded as the largest, oldest and best-preserved earthen site in the present world. However, during the long-term exposure to the environment, remaining earthen structures suffered serious deterioration caused by many influencing factors. The shallow surfaces of the earthen walls can be fully saturated by the concentrated and heavy rains to form flowing slurry, which will be turned into strongly cracked surface crusts during the following intense evaporation and peeled off by wind deflation. In the meantime, salts could be accumulated in the remains to a quite high content, which could exacerbate the deterioration conversely. In this work, desiccation tests were conducted in laboratory on the initially saturated slurry specimens with different thicknesses and NaCl contents and thicknesses. Development of crack patterns on the surface of the specimen was monitored with a digital camera and analyzed using commercialized software. Results indicated that the evaporation process of NaCl-contaminated specimens could be identified as three stages, which has the same configuration as that of salt-free specimens. Cracking behavior of soil that closely correlates to the evaporation process was also influenced. As the NaCl content increases, the CIF values, intersection number, segment number as well as the total crack length decreases. A non-orthogonal crack pattern and orthogonal crack pattern were dominant for thin and thick specimens, respectively. [ABSTRACT FROM AUTHOR]

New Gourna Village, which is located inside one of the World Heritage Sites in Egypt, has never been recognized as an element contributing to the site's Outstanding Universal Value. The recognition of the village as a contributing element is reliant on the successful assessment of its authenticity and integrity. Responding to the dramatically declining integrity of the village, the World Heritage Centre has carried out an architectural study to guide the potential conservation works in the property. The study has recommended that a group of objectives and two approaches to the conservation of the village should be adopted. One of these two approaches has been concerned with the conservation of the village according to the architect's original intentions and principles. The previous approach can be called the principles-based approach. The main aim of this study was to examine the agreement of the World Heritage Centre's objectives and their proposed principles-based approach to the conservation of the village with the aim to improve its chance in meeting the conditions of authenticity and integrity. The study approached the previous aim by assessing, by means of a proposed methodology; the level of significance, authenticity and integrity of the property. Based on the previous assessment, a list of conservation interventions was proposed to improve the property's chance in meeting the conditions of authenticity and integrity. Finally, the World Heritage Centre's recommended approaches and objectives were examined against the previous proposed conservation interventions. The findings indicated the possibility to adopt the principles-based approach to the conservation of New Gourna Village, as well as the other World Heritage Centre's objectives, without limiting the property's chance in meeting the conditions of authenticity and integrity. The study recommends to carry out further studies that are concerned with the identification of the architect's philosophy and architectural principles that should be the key reference of all the potential conservation interventions in the village. [ABSTRACT FROM AUTHOR]

Abstract: The authenticity of earthen heritage has long been a challenge to the trials of the under-represented States Parties, to the World Heritage Convention, to identify properties for listing on their Tentative Lists, of potential World Heritage Sites. Many under-represented States Parties and regions, such as Africa and the Arab States, retain a large number of properties representing earthen heritage, yet none of them has been inscribed on the World Heritage List. For such a pattern of cultural heritage to qualify for the World Heritage Site status, nominated properties should enjoy an Outstanding Universal Value and should also meet the conditions of authenticity and integrity. Due to the fragility of its building material, earthen heritage has always been the subject of continuous maintenance works to its material. Consequently, an impression that the material authenticity of such cultural heritage is questionable has evolved. The main purpose of this study was to discuss such perceptions in further depth. The study also aimed at evaluating the contribution of the “materials and substance” attribute versus the contribution of the other attributes of authenticity, toward the evaluation of the authenticity of earthen heritage. The study approached these objectives by evaluating by means of a proposed methodology the authenticity of one case study, which is Ramses Wissa Wassef Art Centre, in Egypt. The adopted evaluation methodology was developed based on the Nara Document’s notion of authenticity. The findings indicated the significant contribution of the non-material attributes, vis-à-vis the contribution of the “materials and substance” attribute, toward the authenticity of the examined property. The results suggest the need to broaden the narrow perception that reduces the authenticity of earthen heritage to its material aspects, so as to embrace all the other non-material attributes of authenticity. [Copyright &y& Elsevier]

Dryland regions are exposed to extreme environmental conditions that create hotspots of weathering and erosion. Many earthen heritage sites are located in these dryland regions and experience extensive deterioration driven by interactions with environmental processes, however previous research has focused largely on the role of rain as a driver of deterioration. This study combines approaches from geomorphology with understandings of earthen materials from heritage science to investigate the relative importance of wind and rain in driving earthen heritage deterioration in drylands. We use geomorphological signatures to infer the environmental histories of earthen walls with a range of known ages at Suoyang Ancient City, China, using semi-quantitative deterioration assessments. We find rain-driven deterioration features to be associated with the loss of larger volumes of material and to have higher persistence than wind-driven deterioration features. However, we argue that the high frequency nature of wind events means that wind is an important initiator of deterioration across the site. In addition, walls exposed to the prevailing wind are dominated by wind-driven deterioration features. Outcomes from this study present an opportunity for earthen heritage conservation to investigate potential strategies to minimise wind speed at earthen heritage sites in drylands. • Geomorphological signatures reveal drivers of earthen heritage deterioration. • High frequency of wind events in drylands causes substantive cumulative impact. • Wind-driven deterioration features typically have low persistence. • Wind is an important initiator of earthen heritage deterioration. [ABSTRACT FROM AUTHOR]