Historic Building Materials Research Articles

New Vernacular Architecture: Experimental Construction Site in Bärnau, Bavaria

This experimental construction site in Bärnau, a small town on the border between the Czech Republic and Germany, explores innovative approaches to vernacular architecture through a prism of sustainability, craftsmanship, and regionalism. The project addresses three key questions. First, how can we learn from historical building methods and materials to build more sustainably while maintaining social and regional relevance? Second, how to revitalize traditional craftsmanship, focusing on making local materials and techniques more attractive to ensure the preservation of valuable knowledge? Lastly, what potential is there for creating buildings with minimal environmental impact using only regional materials, thereby supporting local economies and ecological integrity?

Strength- and Moisture-Related Studies of Historical Building Materials: A Case Study from Southern Estonia

Demolition of existing buildings turns building products into waste. The amount of demolition waste is increasing globally. The current case study is an example of fulfilling the EU Waste Framework Directive of reducing demolition waste by reuse of historical materials in their original structures. The aim of this paper is to investigate construction materials from 19th and 20th centuries and their mechanical and physical properties in a case study building from the conservation area of Võru city, South Estonia. Timber structures of the case study building were non-destructively tested on-site using a resistive method. Ceramic brick plinth and basement walls, as well as concrete and granite ceiling, were tested in situ non-destructively (rebound hammer test) for compressive strength estimation. Previously dismantled timber logs, slats and ceramic bricks were tested in the laboratory for compression and bending, respectively. The logs and slats matched the European timber bending strength classes C22 and C40, respectively. The compressive strength of the studied ceramic bricks was comparable to that of newly produced bricks. The non-destructive moisture content of timber structures varied in spring (5–20%) but was steady in the autumn (5–7%) tests. The rebound hammer test overestimated by 1.5…2 times the compressive strength of the studied materials compared to laboratory tests.

Chemical, Mineralogical, and Petrographic Analysis of the Mud Mortar from Fort Ikoma Historical Building in Serengeti National Park, Tanzania

The restoration of historical buildings especially the Fort Ikoma in Serengeti National Park, Tanzania requires knowing the material properties used in their construction by characterizing the composition and properties of the mortar to inform the sustainable restoration strategies. Hence, the objective of this paper was to investigate the chemical, mineralogical, and petrographic analysis of the mud mortar from the Fort Ikoma historical building in Serengeti National Park, Tanzania using appropriate standard methods. The results indicated predominant compositions by weight of mud mortar through chemical analysis were silica (59.82%), alumina (20.42%), and Iron (III) oxide (11.07%), which contributed to the higher pozzolanic activity (91.31%) and cementitious properties (Cementitious Index of 46.76) of the historical mud mortar. Mineralogical analysis revealed that a high amount of quartz (38%), nacrite (17%), and other materials such as albite, chlorite, and nepheline put up the ability of mud mortar to resist environmental pressures. The findings contribute to awareness of historical building materials and provide the technical basis for restoring the Fort Ikoma historical building in Serengeti National Park, Tanzania, and similar historical buildings.

Modelling the Mechanical Effect of Salt Weathering on Historical Sandstone Blocks through Microdrilling

The durability of sandstones of historical building materials and geoheritage landforms is a major issue that requires an assessment methodology to follow salt weathering evolution. The building blocks of monuments support decorative carvings and reliefs that are outstanding testimonies of human activity. An evaluation based on quasi- and non-destructive testing is a reliable and generally accepted way of testing and inspecting historical building materials. Compression tests were performed on specimens of similar building sandstones extracted close to those of from St. Leonard’s Middle Ages Church, and microdrilling tests were carried out on adequate blocks of this monument. The locations of the latter tests were determined using the results of low-pressure water absorption tests, which contributed to finding a link between the sandstone specimens and the building blocks of the monument. This innovative methodology was used to generate simulated stress–strain diagrams of the building blocks of this church based on drilling strength results, avoiding the cutting of specimens from the façades with the sizes needed to ensure the mechanical validity of the results. A good agreement between the predicted and experimental stress–strain curves was achieved. The stress–strain curves of sound stones from historical building blocks and of their weathered envelopes are shown. The evolution of weathering profiles can be followed through the analysis of stress–strain diagrams, allowing an assessment of structural stability, which is essential to the study of the durability of historical building sandstones. This innovative methodology allows the adequate conservation of monuments and is a contribution to the knowledge of sustainable cultural tourism.

Developing Low Cost Eco-friendly Restoration Mortars for Historic Lime-based Stucco and Building Materials

In this work, three formulations based on hydrated lime and eco-friendly additives of powdered brick, fly ash and silica fume were designed to improve repair mortars for historic lime-based stucco and building materials. The microscopic features, physical-mechanical behavior and the microstructure of the prepared mortars were evaluated before and after artificial ageing (by humidity/drying cycles and salt weathering). However, a significant mechanical enhancement was reported for the studied mixes, but the silica fume mix showed a notable failure after salt ageing. The fly ash mix revealed the highest bulk density ratio (1.172 g/cm3) compared to the lime and silica fume mixes. The silica fume mix recorded the lowest percentage of water absorption (35.56%) and apparent porosity (28.11%). Further, the silica fume mix yielded the highest dry compressive strength value (22.19 kg/cm2), with an increase reached 31% when compared to the standard lime mix. The results demonstrated that the fly ash mortar is more compatible for sustainable restoration procedures of historic lime-based structures in respect of the physical-mechanical properties.

RESTORATION COMPOUNDS FOR TERRAZZITE PLASTER ON THE EXAMPLE OF CULTURAL HERITAGE SITES OF THE 20TH CENTURY (RUSSIA)

Inroduction: Gradual destruction of buildings or structures of historical significance is a natural process that cannot be stopped. Therefore, preservation of architectural monuments is one of the most important areas of restoration activity. Complete replacement of damaged building materials of architectural monuments changes the historical appearance, and thus cultural sites are stripped of their original look. Innovations in the re-creation of historical building materials and technologies help preserve historical continuity. The purpose of the study was to develop a number of compounds of terrazzite plaster mixtures for cultural heritage sites of the 20th century, which, from an aesthetic point of view, will not allow the loss of the natural and picturesque appearance of the monument, and will be able to preserve the “patina of time”. As a result of the research, the authors studied the compositions of the selected samples, proposed restoration compounds of terrazzite plaster, and determined the algorithm for applying an analogue of the historical plaster. In terms of technical and economic indicators, the developed restoration compounds are effective and make it possible to return architectural monuments to their original appearance with minimal costs. Based on the results obtained, conclusions were drawn about the feasibility of using the proposed new components in terrazzite plaster mixtures to increase strength and ensure high-quality adhesion of the old and new plaster layers. The proposed technology contributes to the return of architectural monuments to their original appearance without losing the historical authenticity of the buildings.

Investigating the historical building materials with spectroscopic and geophysical methods: A case study of Mardin Castle

Today, the building materials form the historical buildings are being exposed to various deteriorations increasingly due to different causes. Many historical masonry constructions in the world are on the edge of extinction due to the increasing frequency and changing models of material deterioration. The materials as close as possible to the original materials in terms of their chemical compositions and physical properties are required in the reconstruction and maintenance of the buildings that have historical importance. In addition, the properties of the materials used in the historical buildings are generally not known with a sufficient accuracy. This causes misapplications in case of emergencies, and also may lead to future potential greater damages on the building. The lack of data regarding the engineering properties of these buildings causes long-term damages on the buildings due to inappropriate conservation methods and materials. Therefore, it is necessary to investigate the properties of certain materials for application in the renewal of the historical buildings. Within this context, in this study the construction materials of Mardin Castle, which is located in Mardin Province, Turkey and existing for centuries as the symbol of the city, are investigated and its properties are reached. Experimental research methods were used in the study. Primarily, the castle structure was examined on-site by field study and sampling was carried out from the areas determined. The samples were analyzed via various spectroscopic and geophysical methods, and various findings were achieved. Relatively variable and high levels of salinization were determined in the findings regarding the average values in stone samples of Mardin Castle’s Fortification Walls. Results of the research document the conservation status regarding Mardin Castle and provide an experimental base and also a theoretical support for the conservation of historical buildings in Turkey; and present indicative suggestions to establish conservation schemes of the historical buildings.

Automatic thermograms segmentation, preliminary insight into spilling drop test

ABSTRACT The spilling drop test (SDT) is a non-destructive test that uses passive thermography to characterise the property of the building surfaces to absorb and diffuse water. However, the drops made visible by the evaporation process, show unclear contours that do not allow easy quantification of the wetted area. In this work, three image segmentation methods based on different statistical treatments have been considered in order to estimate the wet area. The information acquired by spilling drop test were also compared with standardised methods for the assessment of moisture in porous geomaterials. In addition, the pore size distribution was assessed by nuclear magnetic resonance. The proposed methods were tested by analysing a set of ancient Roman plasters and modern mock-ups to highlight the ability of the thermographic method to provide useful information in the field of conservation of historical building materials.

Quantification of Humidity and Salt Detection in Historical Building Materials via Broadband Radar Measurement

For the investigation of moisture and salt content in historic masonry, destructive drilling samples followed by a gravimetric investigation is still the preferred method. In order to prevent the destructive intrusion into the building substance and to enable a large-area measurement, a nondestructive and easy-to-use measuring principle is needed. Previous systems for moisture measurement usually fail due to a strong dependence on contained salts. In this work, a ground penetrating radar (GPR) system was used to determine the frequency-dependent complex permittivity in the range between 1 and 3 GHz on salt-loaded samples of historical building materials. By choosing this frequency range, it was possible to determine the moisture in the samples independently of the salt content. In addition, it was possible to make a quantitative statement about the salt level. The applied method demonstrates that with ground penetrating radar measurements in the frequency range selected here, a salt-independent moisture determination can be carried out.

Archaeoacoustic measurement and simulation of the Jesuit Chapel at St. Mary’s City, Maryland

St. Mary’s City, Maryland was the original capital of Maryland, founded as a colony with protections for Catholics by Lord Baltimore. As a result of the colony’s religious toleration, the city built a permanent Jesuit chapel, the earliest brick structure in Maryland, in 1667. The chapel was one of the earliest brick worship spaces in America, and the only permanent Catholic worship space in the English-speaking world. When Protestants later took control of the state and moved the capital away, the chapel was closed by the governor, and the Jesuits recycled its materials into other structures. As part of archaeological excavation and heritage preservation efforts at St. Mary’s City, the Jesuit Chapel was rebuilt according to historic building practices and materials in the 2000s. The reconstructed chapel was known for its pleasant acoustics by many in the area, and impulse responses were measured in the rebuilt space. The measurements were used to calibrate a geometric acoustic model of the space, which is used as a starting basis for the acoustics of the original 1667 chapel. Some discussion is given to the role of physical versus virtual reconstruction in heritage acoustics and archaeoacoustic projects.

Hygric and thermal properties of Slovak building sandstones

Recently, the simulation software (HAM) used for heat and water transport has become a powerful tool for the hygrothermal analysis of building envelopes, particularly for historical buildings. The increased moisture content and poor thermal-insulation properties of historical building materials increase the risk of damage to the masonry and surface finish. Renovation design and reconstruction is a complicated process. Input data such as boundary conditions, initial conditions, and material properties are required to model the complex heat and water transfer in buildings using a simulation tool. This study focuses on determining the hygric and thermal properties of sandstone from locations in eastern Slovakia that were previously used for historic building construction. The basic thermal, water storage, and water transfer properties were determined using experimental methods. An accurate description of these parameters allows for dynamic simulations of hygrothermal behaviour using the HAM simulation tools for the purposes of restoring historical buildings of immense heritage significance.

ЗАЩИТА ФАСАДОВ ОБЪЕКТОВ КУЛЬТУРНОГО НАСЛЕДИЯ ОТ ВОЗДЕЙСТВИЯ КОСОГО ДОЖДЯ: ОБЗОР ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ

The relevance of the study is due to the fact that erosion of the surface of building materials is a common phenomenon observed on the facades of historic buildings. Climatic changes can lead to an increase in the frequency and intensity of extreme precipitation, which can increase the erosion effects on the facades of buildings due to the wind-driven rain. The purpose of the study is to compare experimental methods for assessing the degree of surface erosion of historic building materials under the influence of wind-driven rainfall. The objectives of the study are to review modern methods for measuring the effect of rain with wind on the surface erosion and reduction of the strength of brick and limestone; to critically analyze the best-known methods for assessing the degree of erosion of the surface of building materials; to offer recommendations for the protection and restoration of damaged facades of cultural heritage objects due to the wind-driven rain. The significance of the obtained results for architects and designers is that the use of methods to assess the degree of damage to the facades of architectural monuments due to wind-driven rainfall makes it possible to monitor and develop measures to protect objects of cultural heritage.

DB-HERITAGE Building Materials Data Aggregation in ARIADNE - challenges and opportunities

DB-HERITAGE provides open and free sharing of wide-ranging technical data on hundreds of samples of building materials from diverse periods, extracted from Portuguese built heritage all over the world. It has been developed to improve know-how for historic building materials and as a basis for developing best practices for built heritage conservation. It incorporates both physical and digital repositories for building material samples and related data, providing tools for the systematic recording of data concerning the history, properties, and performance of materials used in Portuguese built heritage. DB-HERITAGE targets different communities, researchers, and stakeholders involved in the preservation of archaeological and architectural heritage. It provides a systematisation of building assets, within their related environmental, social, and cultural contexts, as well as displaying technical and scientific information on structural elements, built components and their constituent materials. Although the rationale of the wide context sustaining the DB-HERITAGE concept, gathering communities and reduced time-to-value represent extra requirements for data quality, improved tools, and an efficient management plan. The participation in ARIADNEplus challenged DB-HERITAGE to get the most out of standardised procedures and the FAIR principles, strengthening its data management plan and practices. Data processing has been improved by deploying a common ontology and further developing standards, shared semantics, and identifiers. Updated protocols for data sharing and detailed information on provenance have also been developed to enhance data reuse. This article presents an overview of the aggregation process of DB-HERITAGE data into ARIADNEplus. It includes a summary of DB-HERITAGE’s strengths and of the challenges faced within the scope of the aggregation process, with examples of some of DB-HERITAGE’s major outputs. Additionally, it considers the benefits and opportunities provided by participation in ARIADNEplus.

Microclimate and Weathering in Cultural Heritage: Design of a Monitoring Apparatus for Field Exposure Tests

An innovative experimental method for the long-term monitoring of outdoor microclimate and material decay at cultural heritage sites was developed to aid the formulation of new damage functions and models for climate-change risk assessment. To that end, an apparatus for field exposure tests was designed to monitor a variety of historical building materials in different environmental settings. The data series acquired, i.e., surface temperature and moisture, are compared with the corresponding meteorological datasets on a local and regional scale. The apparatus is designed for supporting also the monitoring of the physical and chemical changes caused by weathering. This novel method is expected to provide insights into the interaction between historical materials and the environment, which can be exploited for the protection and conservation of cultural heritage.

Pore structure and interdisciplinary analyses in Roman mortars: Building techniques and durability factors identification

Microstructural and compositional analysis of historical mortars is an active research field, not only to guarantee the use of compatible repair measures, but also to guide the design of novel efficient materials. Despite the crucial role of Roman mortars in building history, there is a significant lack of knowledge of their pore system in relation to building techniques and durability. From these premises, this research focuses on the structural mortars of the Realillo aqueduct (Archaeological Site of Baelo Claudia, Spain). This construction is especially interesting from a durability point of view, as in addition to being in a windy coastal area, the water-proof potential of the material is a major issue. Complementary experimental techniques (petrography, computed tomography, X-ray fluorescence, X-ray diffraction (micro and conventional), thermal analysis, pycnometry, physisorption, Hg porosimetry, and SEM-EDS) are applied within a multidisciplinary approach, including the Vitruvian guidelines and comparative analysis with coetaneous buildings. The size and shape of the pores and the porous volume distribution have been linked to hydraulicity, and to cohesion and weathering resistance. Total and open porosity can be related to waterproof worsening, and the entrapped air pores detected could indicate inadequate placement. The shrinkage cracks can be related to the sea sand aggregate. Thermal analysis and C-A-S-H gel indicate hydraulic phases, but with different hydraulicity levels. This variation could be related to the non-high-purity limestone and/or to the recipe. The differences in binder/aggregate ratios and petrographic classification confirm the distinct compositions. Non-standardized manufacturing or building stages could be related to compositional variations. This research has provided significant insights into durability and manufacturing issues by integrating a micro–macro pore structure study within multianalytical and interdisciplinary research. The method may be used as a complementary procedure to characterize historical mortars. As upgrading/degrading durability factors were obtained, a conservation campaign could be designed. In addition, knowledge about historical building techniques and materials has been enriched.

Thermophysical parameters of the Kežmarok sandstone

Thermophysical parameters of building materials are required for calculating the complex heat and water transfer in building structures. It can be performed by modern simulation software such as Wufi, Delphin, Math, Comsol Multiphysics and other. This software is suitable for evaluation of water and heat transport in construction of historical buildings, because it can include the impact of water on material properties, driven rain, ground water, heat and water accumulation and other. The material properties of historical building materials are required for the use of this software. In Slovakia, the most used building material was sandstone. Sandstone from Kežmarok was chosen for this paper, which was used in the construction of historic buildings such as churches and town houses. The method of dynamic impulse transition by thermophysical tester RTB was used to determine the thermal properties of sandstone.

Biodeterioration of Glass-Based Historical Building Materials: An Overview of the Heritage Literature from the 21st Century

The main goal of this work was to review the 21st century literature (2000 to 2021) regarding the biological colonisation and biodeterioration of glass-based historical building materials, particularly stained glass and glazed tiles. One of the main objectives of this work was to list and systematize the glass-colonising microorganisms identified on stained glass and glazed tiles. Biodiversity data indicate that fungi and bacteria are the main colonisers of stained-glass windows. Glazed tiles are mainly colonised by microalgae and cyanobacteria. Several studies have identified microorganisms on stained glass, but fewer studies have been published concerning glazed tiles. The analysis of colonised samples is a vital mechanism to understand biodeterioration, particularly for identifying the colonising organisms and deterioration patterns on real samples. However, the complexity of the analysis of materials with high biodiversity makes it very hard to determine which microorganism is responsible for the biodeteriogenic action. The authors compared deterioration patterns described in case studies with laboratory-based colonisation experiments, showing that many deterioration patterns and corrosion products are similar. A working group should develop guidelines or standards for laboratory experiments on fungi, bacteria, cyanobacteria, and algae on stained glass and glazed tiles.

The Effects of Hydrogen Fluoride on the Wooden Surface of Historic Buildings during Fire Suppression Using Fluorinated Chemical Gases

ABSTRACT Chinese historic buildings are characterized by a wooden structure, which has caused serious results due to the ravages of frequent fire disasters. After the weathering by the natural environment, the fire risk of wood is highly enlarged. Fluorinated chemical gases are widely used for fire suppression at the early stage of a historic building fire. However, the effects of hydrogen fluoride (HF) released during fire suppression on historic buildings are unavailable. Presently, experiments were performed to study HF effects on the weathered timbers. Five traditional fluorinated chemical gases, H-37, FK-5-1-12, H-1323, H-2402, and H-1301, are employed to suppress a fixed flame. The weathered timber chips, acting as historic building materials, are located in the chamber to detail the influence of HF on the surface. The characteristic of gas production and elements variety of wood surface are discussed by FTIR and SEM-EDX, respectively. It is observed that flame enhancement takes place at the early stage of fire suppression and various types of fire agents. The total amount of HF during 50 min is highly dependent on the physical parameters of fluorinated chemical gases. The SEM results of weathered timber suggest the surface of the wood is porous, resulting in a strong gas absorption performance. The amount of deposited F on the wood surface is found to be positively correlated with the total amount of HF yielded during fire suppression.

The problem of conservation of XX century architectural heritage: The fibreglass dome of the woodpecker dance club in Milano Marittima (Italy)

The present study deals with the deterioration of materials in the dome of the “Woodpecker” dance club designed by the architect Filippo Monti (1928–2015) and built in Milano Marittima (near Ravenna, Italy) in 1968. This place, considered extremely valuable due to its landscape and architectural features, has been in a state of abandonment for around 40 years, but recently the local Municipality has started a process for its restoration. The dome is made of 23 fibreglass precast rib vaults hiding a steel structure, and in early 2000s a large part of its internal surface was painted with a graffito by Blu, an internationally renowned Italian street artist.Nowadays, both the dome and the graffito are safeguarded for their historic-architectural-artistic value by putting restrictions to their demolishment and modification. However, both the dome and the graffito are affected by harsh kinds of degradation, very different from those affecting historical building materials, which endanger their state of preservation.This study investigates whether the methodological approach of the conservative restoration can be applied to this structure, which is an example of contemporary architecture. Because of the lack of project drawings, a visual investigation was carried out to define geometric features and the most important technical details, and to deduce plausible hypotheses about building techniques that were adopted. The degradation affecting the dome and the graffito was then investigated, and samples of fibreglass, steel and paint were collected. Laboratory analyses on these samples, in addition to environmental studies concerning wind, ground water and relative humidity, were conducted to characterize the materials and identify their main deterioration processes.A possible restoration solution in accordance with conservative restoration principles was finally proposed, showing that the application of the same methodological approach used for ancient buildings arises many challenges, due to some key peculiarities of XX century architectural heritage materials.

Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis.

In the present paper, the identification of the material parameters of a masonry lighthouse is discussed. A fully non-invasive method was selected, in which the material properties were determined via numerical model validation applied to the first pair of natural frequencies and their related mode shapes, determined experimentally. The exact structural model was built by means of the finite element method. To obtain experimental data for the inverse analysis, operational modal analysis was applied to the structure. Three methods were considered: peak picking (PP), eigensystem realization algorithm (ERA) and natural excitation technique with ERA (NExT-ERA). The acceleration’s responses to environmental excitations, enhanced in some periods of time by sheet piling hammering or by sudden interruptions like wind stroke, were assumed within the analysis input. Different combinations of the input were considered in the PP and NExT-ERA analysis to find the most reasonable modal forms. A number of time periods of a free-decay character were considered in the ERA technique to finally calculate the averaged modal forms. Finally, the elastic modulus, Poisson’s ratio and material density of brick, sandstone and granite masonry were determined. The obtained values supplement the state of the art database concerning historic building materials. In addition, the numerical model obtained in the analysis may be used in further cases of structural analysis.