1,720,975 research outputs found
Study of calcium ethoxide as new solution for the consolidation of carbonate stones
Full text linkThe combined action of several physical, chemical and biological factors cause the weathering of stone widely employed in the field of Cultural Heritage. These deterioration processes are well studied and the results have promoted the research of compatible, efficient, stable and long-lasting consolidation treatments to overcome the limitations of traditional ones and to meet the requirements of the historic building substrates. Within this context, during the European collaborative project NANOMATCH, different consolidating agents for carbonate supports, as calcium alkoxides, were synthesized and applied.
The present works aimed at studying the properties and, especially, the effectiveness of one of these products - calcium ethoxide - as stone consolidant. This product is considered a promising alternative to traditional treatments for the consolidation of carbonate stones, since it meets one of the key requirements in the field of conservation of Cultural Heritage, such as the chemical compatibility with the support. In fact, calcium ethoxide, dissolved in a proper organic solvent, penetrates within the porous substrate and, reacting with moisture and carbon dioxide of the atmosphere, forms a calcium carbonate coating on the pore walls. The investigation started with a first characterization of calcium ethoxide diluted in different solvents - chosen for their different boiling point and because they are actually used in the restoration field - through a study of the carbonation process: its kinetics, reaction pathway and evaluation of mineralogical phases formed at the end of this process. Subsequently, the consolidant was applied on carbonate stones with different total open porosity value and a multi-technique approach was used for the assessment of its performance - compatibility and efficacy - as consolidating agent, by comparison with a commercial product This work has revealed important information regarding the influence of environmental conditions and used solvent on the carbonation process of calcium ethoxide and therefore, on its potential as consolidating treatment for carbonate supports
Behaviour of brick-NHL render systems in presence of NaCl solution
Full text linkDouble-layer renders were formulated for ensuring salt migration, ancient masonries conservation and environmental sustainability. Thus, natural hydraulic lime as binder and recycled aggregates from render wastes were selected. The properties were adjusted by adding an air-entraining agent in the inner layer and different percentages of water-repellent admixtures in the outer layer. The systems were applied on bricks and subjected to rising damp-evaporation cycles, for investigating their behaviour and properties in respect to NaCl migration. Mono-material prismatic render specimens were also studied. Water vapour permeability, capillary absorption, drying behaviour, compressive strength, mechanical resistance, conductivity and porosity of each formulation were evaluated. Good durability was observed whenever the render layers had different microstructure, either there was salts deposition within the lower layer,or if there was tefflorescences formation. If the layers had similar structure, deposition of salt at the brick-render interface occurred causing damages to the substrate.Se ha formulado una doble capa de revestimiento para garantizar la migración de las sales, la conservación de fábricas y mamposterías antiguas y la sostenibilidad del medio ambiente. De este modo, se seleccionó cal hidráulica natural y áridos reciclados de residuos de revestimientos. Además, se ajustaron y regularon las las propiedades mediante la adición de un agente aireante y de en la capa interna y de diferentes porcentajes de mezclas hidrorrepelentes en la capa externa. Los sistemas han sido aplicados sobre los ladrillos y sometidos a ciclos de humedad ascendente y de evaporación para investigar su comportamiento y propiedades respecto a la migración de ClNa. También se han estudiado especímenes prismáticos monomateriales de revestimiento. Para cada formulación se evaluaron la permeabilidad al vapor de agua, la absorción capilar, el comportamiento de secado, la resistencia a compresión, la conductividad y la porosidad. Cuando las capas del revestimiento presentan diferente microestructura se produce bien la deposición de sales en la capa inferior, bien transporte a la superficie y formación de eflorescencias, observando una buena durabilidad. Si las capas tienen estructura similar, se produce la deposición de sales en la interfaz ladrillo-mortero, originando daños al substrato
Interactive Learning Method of Cultural Heritage for Europeanization in the Danube Region – ILMECH
Full text linkThe project will contribute to raising awareness of tangible (TCH) and intangible (ICH) cultural heritage of Danube Region (DR) by providing modern and innovative tools for teaching its essence to youth. In the DR there is a lack of a common European identity due to the historical, economic, and political backgrounds. The integration process has been slowed down due to the political instability and different development among the countries of the area. Youth, that will become the future European citizens and the real prospective for the development of their countries, are not much influenced by the memories remaining of the turbulent past of DR. Therefore, they are a sensible target to achieve an Europeanization of this area. To reach this aim, the project will introduce a common and interactive didactic method for the whole DR that teaches to high school pupils the proper value of their TCH and ICH in order to achieve an Europeanization prospective. This method includes “From practice to the theory” approach, “Do it yourself”
experience and integration of innovative augmented reality ICT tools (3D reconstruction, educational videos and games). Moreover, the project will provide a web platform in which e-learning courses, free documentation regarding the didactic method developed, ICT tools database and guidelines on their use will be available. Dissemination action among schools will be carried out in order to promote the use of the proposed materials
The Efficiency of Biocidal Silica Nanosystems for the Conservation of Stone Monuments: Comparative In Vitro Tests against Epilithic Green Algae
Full text linkIn the last decade, worldwide research has focused on innovative natural biocides and the development of organic and inorganic nanomaterials for long-lasting reliability. In this work, the biocide effects of two different biocides encapsulated in two different silica nanosystems for a multifunctional coating have been performed through in vitro tests, by using Chlorococcum sp. as a common stone biodeteriogen. Zosteric sodium salt (ZS), a green biocide, was compared with the commercial biocide, 2-mercaptobenzothiazole (MBT), widely used in the treatment of cultural heritage. The analyzed systems are the following: silica nanocapsules (NC) and silica nanoparticles (MNP) not loaded with biocides, two nanosystems loaded with ZS and MBT, and free biocides. The qualitative and quantitative evaluations of biocide efficiency were performed periodically, analyzing pigment autofluorescence to discriminate between active and inactive/dead cells. The analyses showed multiple differences. All the nanocontainers presented an initial reduction in chlorophyll’s autofluorescence. For the free biocide, the results highlighted higher efficiency for MBT than ZS. Finally, the nanosystems loaded with the different biocides highlighted a higher activity for nanocontainers loaded with the commercial biocide than the green product, and better efficiency for MNP in comparison with NC
Interactive Learning Method of Cultural Heritage for Europeanization in the Danube Region – ILMECH
No full textThe project will contribute to raising awareness of tangible (TCH) and intangible (ICH) cultural heritage of Danube Region (DR) by providing modern and innovative tools for teaching its essence to youth. In the DR there is a lack of a common European identity due to the historical, economic, and political backgrounds. The integration process has been slowed down due to the political instability and different development among the countries of the area. Youth, that will become the future European citizens and the real prospective for the development of their countries, are not much influenced by the memories remaining of the turbulent past of DR. Therefore, they are a sensible target to achieve an Europeanization of this area. To reach this aim, the project will introduce a common and interactive didactic method for the whole DR that teaches to high school pupils the proper value of their TCH and ICH in order to achieve an Europeanization prospective. This method includes “From practice to the theory” approach, “Do it yourself” experience and integration of innovative augmented reality ICT tools (3D reconstruction, educational videos and games). Moreover, the project will provide a web platform in which e-learning courses, free documentation regarding the didactic method developed, ICT tools database and guidelines on their use will be available. Dissemination action among schools will be carried out in order to promote the use of the proposed materials
Evaluation of Eco-Compatible Methodologies to Clean Stone Surfaces Polluted by Oil Spill
Full text linkThis research concerns the structuring of a suitable method for the removal of oil (Fuel Oil
120 cSt) from traditional bricks and Istrian Stone, materials commonly found amongst
embankments and buildings of North Adriatic coastal cities. A cleaning protocol, based upon
non-toxic products, was developed in consideration of its compatibility with historical,
architectural surfaces. The contamination effects of oil on Istrian stone and fired clay bricks
was studied, followed by a range of cleaning treatments using bulk sorbents, surfactant
solutions and N,N-dimethyl-octanamide. The application was executed using the products
singularly, combined or in succession. The succession of sorbent, solvent and surfactant
solution demonstrated good capability of removal and was then applied on macrosamples of
brick masonry showing good results
Comparison between NMR and MIP in characterizing porosity of limestone used in Cultural Heritage,
No full textThe “Restoration of the Restoration”: Investigation of a Complex Surface and Interface Pattern in the Roman Wall Paintings of Volsinii Novi (Bolsena, Central Italy)
No full text(1) Background: The present paper reports the results of the analyses performed on the wall paintings of Room E of the Domus delle Pitture (Room of the Paintings) in the Roman archaeological site of Volsinii Novi (Bolsena, Viterbo, Central Italy) aimed at supporting the recently concluded restoration. (2) Methods: ultraviolet fluorescence photography was conducted to evaluate the conservation state. Painting materials were investigated via portable X-ray fluorescence spectrometer (p-XRF), mu -Raman spectroscopy, cross-section analysis under polarizing microscope, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared (FTIR) spectroscopy. (3) Results: This analysis revealed the presence of traditional pigments used in Roman wall paintings, such as ochres, earths, and Egyptian blue. Additionally, it identified pigments from previous restoration containing titanium and chromium, along with other materials present in the surface and interface of the wall painting containing arsenic, copper, lead, and vanadium, where a bluish alteration was observed. In these samples, mu -Raman spectroscopy detected calcium oxalates but also copper arsenates, likely conichalcite and/or duftite. (4) Conclusions: This result is highly relevant from an analytical point of view and in relation to the restoration decisions. Addressing the irregular bluish stains on the wall paintings poses challenges in understanding, requiring a decision on whether to remove or retain them
Study of Calcium Ethoxide as a New Product for Conservation of Historical Limestone
Full text linkThe combination of multiple physical, chemical and biological factors causes the weathering\ud
of limestone used in the field of cultural heritage. To overcome the limitations of traditional\ud
consolidating products and to meet the requirements of the historical building substrates, during\ud
the European collaborative project NANOMATCH, alkaline earth alkoxides were developed and\ud
studied as consolidating agents for limestone. Among these new products, calcium ethoxide, with the\ud
formula Ca(OEt)2, was chosen for this study and investigated in depth as an alternative consolidating\ud
treatment. It was first characterized through a study of the carbonation process: its kinetics, reaction\ud
pathway and the evaluation of formed mineralogical phases. Subsequently, it was applied on\ud
limestones with different total open porosity to test its performance as a consolidating agent.\ud
The compatibility and the efficiency of the treatment were investigated with a multi-technique\ud
approach and compared with results obtained with a reference product, based on nanolime.\ud
This study indicates that calcium ethoxide shows better results with respect to the reference product,\ud
both in terms of compatibility and consolidation effect
Effectiveness and Compatibility of Nanoparticle Based Multifunctional Coatings on Natural and Man-Made Stones
Full text linkThe interaction of microorganisms with stone materials leads to biodeterioration processes, which may cause aesthetic damages and the loss of durability and strength of the substrates. Innovative solutions against this process are represented by nanotechnologies. In our previous works, 2-mercaptobenzothiazole was successfully encapsulated within two silica-based nanodevices: nanocapsules and mesoporous nanoparticles. Such loaded nanodevices have been dispersed in TEOS based coatings, characterized as far as their chemical–physical properties and in vitro biocide efficacy. Here, we adopt a multi-technic approach, to assess the coatings efficacy and compatibility with four types of stones of cultural heritage interest, namely, mortar, brick, travertine, and Carrara marble. In particular, we determine the protective function of the coatings, based on water transport properties (reduction up to a factor 10 of the water absorption for brick and mortar, without significantly influencing water vapor transmission rate), morphology of the surface (absence of coating cracks and color changes), and TiO2 photocatalytic activity. Consequently, these coatings can be considered suitable for application on stone artifacts, without interfering with their artistic appearance
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