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1.
Adobe is a construction technique that uses raw earth mixed and moulded to form sun-dried blocks to realize a bearing wall. The recent discovery of adobe walls belonging to a Republican domus sited in Suasa (Ancona, Italy) was the starting point of the present work. The research was developed through an experimental approach, in order to characterize the mechanical behavior of this type of walls: firstly some adobe blocks similar to the original ones were reproduced by using the soil directly came from the archaeological site near the adobe walls and adding straw to reduce hygrometric shrinkage and coarse sand, taken from a local quarry, as a stabilizer, as Romans were used to do. Then, after a seasoning period of 4 months, four adobe walls were produced to be tested by compression and shear. From compression tests, maximum strength, first cracking compression stress, Young modulus and breaking manner were evaluated. As well, compression results show a possible two-storey structure of the earthen Republican domus. In fact, it appears that the stress from the two-storey load analysis is lower than the first cracking compression stress. From the shear tests, a proportional law seems to regulate the relation between the maximum value of the mean tangential tensions and the vertical compression the sample is subjected to. This could be the starting point for a future seismic analysis.  相似文献   

2.
Adobe is a construction technique that uses raw clayey earth mixed and moulded to form blocks to realize a bearing wall. Romans were also used to add sand or coarse sand into the mixture to “degrease” clay and to allow to make it into a mixture. Fibres such as straw were often added into the mixture. Anyway, ancient home brick-makers have not had a chance to do scientific experimental investigation on the balance of ingredients and the optimisation of this production. This paper elaborates on how workability and mechanical properties of Roman ancient adobe earthen bricks change by varying the percentage of an on situ soil, straw and coarse sand into the mixture to produce them. The comparisons were also made with the only-earth samples. Breaking manners of all the samples were also compared.  相似文献   

3.
Epoxy resins, widely used in conservation, still remain controversial materials. Considering some of the drawbacks that currently limit the application of epoxy consolidants, we present the application of the cationic ring opening polymerization as a novel method to cure the epoxy monomer in the restoration field. The cationic polymerization was carried out through a redox system based on the reduction of the iodonium salt in the presence of ascorbic acid catalyzed by a copper salt. The use of this initiator system for carrying out a suitable consolidant for lime plaster is considered. First, the film properties of the cured films were investigated. Then, the formulation was applied on a sample of plaster and its compatibility was verified. Its effectiveness as a consolidant product is explored through the evaluation of chromatic changes, mechanical strength, morphology of the re-aggregated material, and changes of the surface properties.  相似文献   

4.
Organic-inorganic lime mortars were widely used in many ancient buildings due to their good performance in some fields (such as caking property, water repellency, weatherability, etc.). However, many ancient buildings and sites are suffering from various degrees of damage with the development of the economy and society and appropriate conservation and restoration are needed. The application of traditional construction materials, such as organic-inorganic lime mortars, attracts more and more attention in the conservation and restoration of ancient buildings in the recent years. So, the understanding of the components of original lime mortar which remained in ancient sites is of fundamental significance. In this work a set of analytical procedures to identify the organic additives in lime mortars by classical chemical analysis is proposed. The results show that using iodine-potassium iodide reagent, Benedict's reagent, reduction phenolphthalein reagent, Coomassie brilliant blue and sodium periodate oxidation glycerin acetyl acetone method could effectively detect a small amount of starch, reducing sugar, blood, protein and fatty acid ester that remained in ancient buildings’ lime mortars, respectively. These analytical methods are easy to operate with low detection limit, high accuracy and some other advantages.  相似文献   

5.
Assessment of multi-leaf stone masonry in earthquake-prone areas is mostly related to the evaluation of its texture, morphology, leaf detachment and structural cracking due to previous seismic activity, as well as disintegration due to material deterioration. For the plastered masonry with heritage or artistic value (paintings, frescoes etc.), both the type of structure and the extent of damage should be characterized with minimal interference to the structure, which could be overcome solely by non-destructive testing (NDT). However, due to the complexity of plastered multi-leaf masonry structure, the performance of well-known NDT methods could be significantly worsened. Therefore, as a prerequisite for applying NDT on multi-leaf stone masonry in practice, a validation process should be carried out. In this study, complementary ground penetrating radar (GPR) and infrared (IR) thermography measurements on plastered laboratory three-leaf stone masonry walls were performed. Apart from assessing the wall texture and morphology with the type of connection between the leaves, detection of gradual plaster delamination and crack propagation while subjecting the walls to an in-plane cyclic shear test was taken into account. The results showed that GPR could successfully visualize header stones passing through the whole depth of the specimen. The masonry texture behind the plaster could be well resolved by both methods, although GPR near-field effects worsened its localisation. For the detection of plaster delamination, IR thermography outperformed GPR by detecting delamination as small as 2 mm as well as structural crack patterns, whereas GPR only detected delamination larger than 8 mm. It was shown that the performance of both methods for defect detection could be further improved by image fusion based on unsupervised clustering methods.  相似文献   

6.
Organic-inorganic materials to be used as hydrophobic consolidants for plasters were synthesized starting from an inorganic precursor (Tetraethoxysilane [TEOS]), added to a polysiloxane epoxy formulation and thermally cured with Ytterbium as acid catalyst. The TEOS reduces the viscosity of the resin, contributing to the mechanical properties of the film, without causing cracking. Solvents, that are harmful for workers and environment and show some drawbacks in the practice of restoration, were not used. The film properties and the formation of silica clusters were investigated. The products were applied by brush on plaster's samples and their compatibility and effectiveness were verified. Thanks to the organic content, the products penetrate deeply, are more stable to photo-oxidative degradation, and the hydrophobicity of the resin, provided by the silicone component, is not altered.  相似文献   

7.
Ca(OH)2 particles with submicrometric dimensions (nanolimes) are recently introduced in cultural heritage conservation, in order to improve lime treatments. Lime nanoparticles are typically produced by a chemical precipitation process in supersaturated aqueous solutions of the reactants (calcium chloride [CaCl2] and sodium hydroxide [NaOH]); water is then partially substituted with 2-propanol in order to improve stability and to reduce a random orientation of the particles. Aim of the present work is to analyse the influence of the nanolime suspensions concentration on the carbonatation process, in relation to the residual water content too. The obtained lime nanoparticles are characterised by X-rays diffraction (XRD) and profile analysis. Afterwards, the influence of the suspension concentration on stones protective treatments is evaluated: alcoholic nanolime suspensions, characterised by different concentration values, are applied on several natural lithotypes. Standard tests are performed to estimate the superficial consolidation and the protective treatment effectiveness: “Scotch tape test” (STT) and capillarity test. Porosimetric investigations are performed too.  相似文献   

8.
The hewn sandstone and ornamental figures of the Albertino Chancel, built around the mid-14th century, are covered with black encrustations of plaster and carbon deposits, often several millimetres thick. Their removal constitutes one of the main objectives in the conservation of the precious materials of the cathedral. The Nd:YAG laser method cleans the original surface of hardened encrustations without damaging or affecting the old coloured plasters and without affecting the centuries-old patina. Laser-Tech GmbH, founded by two expert restorers from Austria and Italy, is specialised in large-scale projects and, regarding the present project for the chancel, has managed to combine the sensitivity of the preserver with the laser technology applied to large surfaces. The present project concerning St. Stephen's Church comprises over 2000 m2 of stone surface treated only with laser systems, by groups of qualified restorers trained at Altech to use such instrumentation on artistic historic surfaces.  相似文献   

9.
Almost all defects of earthen buildings such as roughening, erosion, volume reduction, cracking as well as crazing, etc., have been witnessed in the ancient city of Jiaohe, an earthen architectural heritage in northwest China. In this paper, their long-term durability and deterioration due to prolonged exposure to environmental factors were studied, based on the basis of field investigation and laboratory analysis. The results indicated that the deterioration of building materials should be attributed to their basic properties, including density, particle size distribution, soluble salts, mineral, mechanical strength, etc., and interaction with environmental factors. And then, four main deterioration modes can be identified, namely: wind-related deterioration, water-related deterioration, temperature-related deterioration and chemical related deterioration. It can be concluded that the greatest deterioration was wind-related deterioration on west-north facing façades, and chemical related deterioration on the surface of building materials.  相似文献   

10.
In the present work, an analytical characterization of painted plaster samples coming from ancient buildings dated back to 2nd cent. B.C., located in Licata (Sicily, Southern Italy), has been carried out. The investigation has been performed through different spectroscopic techniques: X-ray fluorescence (XRF) using an handheld energy-dispersive XRF analyzer, scanning electron microscopy equipped with an Energy Dispersive Spectrometry microanalysis detector (SEM-EDS) and Fourier transform infrared absorbance spectroscopy (FT-IR). The main goal is to identify the plaster and pigments material. In particular, the XRF investigation of surfaces is the first step for a preliminary elemental characterization. Then, through SEM-EDS measurements, a quantitative analysis of the chemical composition of the plaster and the pigmenting agents along with eventual components related to deterioration processes has been obtained. Finally, FT-IR absorbance spectra have proven to be a useful tool to investigate the molecular nature of the used materials.  相似文献   

11.
Historical plasters on light thin vaults, usually made by mats of reeds nailed to an upper wooden framework, were used in several historical and monumental Italian buildings and churches built between the 16th and the 19th century and almost all of the historical Italian theatres built between the 18th and the 19th century to cover the theatre-hall and to improve its acoustic properties. The non-destructive inspection of these structures is very important, but traditional inspection techniques are usually limited in resolution, which may be a problem for detection of defects at a very early stage. The paper presents the development and application of a high-resolution inspection technique based on a hybrid ultrasonic method, where a contact emitter probe and a non-contact air-coupled receiver probe are used. Results show the effectiveness of the method on laboratory samples and propose an inspection procedure for in-field application.  相似文献   

12.
For the last decades, many traditional farm buildings have lost their original function because of the great changes in the European agricultural sector. The respectful conversion of these derelict constructions to adopt new economic or social uses constitutes an interesting practise to protect the rural landscapes and to set in motion complementary gainful activities to the agricultural production. The starting of a regional or local scheme to protect the built heritage in a particular rural area requires an appropriate knowledge of construction techniques and typological characteristics of the traditional architecture. According to the practical experience of the author in Central Spain, this paper deals with the proposal of methodological bases for data collection and subsequent analysis of the vernacular constructions in a particular rural area. The systematic assessment of the suitability for reuse of old agricultural buildings by multicriteria decision-making techniques to ensure the preservation of the most valuable examples is also discussed.  相似文献   

13.
The possible pre-consolidation of the stones used to repair the Roman wall of Tarragona was studied, on the premise that this had been carried out prior to placement in the wall. A detailed study of the stones was conducted in order to determine whether they had been treated, and if so, how this had been done. A semi-quantitative X-ray mineralogical analysis using the Rietveld method was performed, together with porosity and textural analyses. This paper concludes with a discussion of how the stones studied here were pre-consolidated using lime slurry.  相似文献   

14.
Analysis of historic mortars including Islamic, Gothic and later ones taken from palaces, convents and mansions in Palma de Mallorca has been carried out. Scanning electron microscopy (SEM) coupled to energy dispersive X-ray spectrometer (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to characterise the morphology and analytical composition of the samples analysed. Generally, covering plaster mortars presented a low percentage of small size aggregate. The reported results show that mixed and lime mortars have been used, thus, the establishment of a relationship between the type of mortar employed and its age is not feasible. In the painted mortars, polychromy has also been studied. The most common pigments to be found are natural earths.  相似文献   

15.
This paper deals with the impact of soluble salts on the deterioration of wall paintings in the region of Wadi El Natrun in Egypt, including the identification of the building materials and pigments used. For this purpose we used XRD analysis which proved that the green pigment in the Church of the Virgin, Wadi El Natrun is a mix of malachite and hydrocerussite, and the black pigment is graphite. The results proved that the building materials (stones, mortar, and plaster) in Wadi El Natrun are affected by ground water as they have the same soluble salts at different concentrations. The Wadi El Natrun lakes are the native source of natron salt, which has been used in mummification techniques. Soda lakes represent the major types of naturally occurring highly alkaline environments. The factors leading to the formation of the alkaline saline deposits may be divided into climatic, geological, and topographical. Climatic and topographical factors control the amount of water entering the system as rainfall or surface runoff and the amount leaving by evaporation. Geochemical factors determine which ions enter the system. Solutions of carbon dioxide result in the formation of a weak carbonic acid, which dissolutes the mineral components of the surrounding rocks and archaeological buildings, leading to their ion release.  相似文献   

16.
Lime renders are of great importance not only to enhance the appearance of the buildings, but also to protect and preserve old masonries. They constitute a specialized system, composed of several layers, in which each of them depends on the others and carries out some specific functions in order to assure a suitable performance of the whole. Knowledge of the traditional materials and techniques, as well as the know-how, is one of the key points in the maintenance and conservation of lime renders and, by extension, of our Heritage. However, the promotion of the use of cement and the industrialization process, which in the case of Spain took place about the 1960's, caused lime mortars to fall into disuse. In this article, classical treatises as well as the state-of-the-art researches were analysed to compile the properties of lime render layers, on the whole. The knowledge of these characteristics is essential to maintain and repair the existing renders as well as to formulate new compatible ones, while assuring their durability and appropriate performance. Lime is the selected binder for these recommendations because it was widely used as drawn from the literature.  相似文献   

17.
In November 20th 2007 Tel Aviv-Jaffa Municipality confirmed its list of buildings earmarked for conservation. The confirmation was related only to Tel Aviv cultural heritage, the city that was founded in 1909, along the Mediterranean seashore, next to old Jaffa. The list was published 4 years after part of the old urban center of Tel Aviv was nominated as World Heritage Site for its architectural uniqueness (Tel Aviv the White City). The list and the nomination were focused on architectural styles, which are based on building material, the silicate brick, used in Israel throughout the years 1918–1948. This building material and technology left its imprint on Tel Aviv's landscape and is also a part of Tel Aviv's history and development. In spite of its importance, all concerned in Tel Aviv-Jaffa municipality and urban planning, have totally ignored this phenomenon.The thrust of this discussion is that the silicate bricks phenomenon, a building material and technology, due to its importance to Tel Aviv heritage and its vast distribution in Tel Aviv landscape, should be integrated into the current urban renewal development process in the old city of Tel Aviv. The discovery of its history and its role in Tel Aviv cultural heritage will change the attitudes of Tel Aviv-Jaffa municipality to this building material; instead of a vernacular phenomena, a common brick or a frequent building technology, it will get a better appreciation. Urban landscapes of many cities around the world are based on vernacular phenomena, which are ignored by the urban municipalities. The silicate case should serve as an example of the role of a vernacular heritage, and in this case a common building material, in the urban renewal and conservation process.  相似文献   

18.
In many historical and monumental Italian buildings, frescoes or stuccoes of artistic and historical value are present on the lower surface of flat light vaults, made by wooden arches, reeds and plaster. These vaults are often suspended by wooden or metallic ties to the upper bearing structures. When differential settlements of the wooden arches happen (i.e.: due to a bad working of their hangings) cracks appear on these precious surfaces. This paper experimentally and numerically investigates on this issue, pointing out which constructive parameters mainly influence the cracking behaviour of the frescoed or stuccoed lower surface, and thus providing guide lines for designing compatible conservation and retrofitting interventions.  相似文献   

19.
The state of conservation of the frescoes at Qusayr Amra was investigated by integrated physico-chemical measurements, particularly optical and scanning electron microscopy, μ-infrared spectroscopy, mass spectrometry and X-ray powder diffraction.The frescoes appear darkened and severely damaged owing to the deterioration of surface treatments and to the widespread presence of different salts. These caused significant detachments of the painting layers.The materials used in the painting and preparation layers and in the wall plaster were characterized in order to clarify the painting technique. Different pigments have been identified on the pictorial layers: the original ones correspond to green earth, yellow and red ochre, realgar, bone black and lapis lazuli and others, such as titanium white and cobalt blue, ascribed to recent restoration works. Proteinaceous materials (egg or yolk) have been identified as binders for the pigments, indicating a tempera painting technique.Three different products, belonging to restoration interventions, have been also identified: the natural product shellac, ascribable to next-to-last restoration and scarcely removed during last restoration also because of its insolubility, the synthetic vinyl acetate and acrylic polymers. Particularly the latter one indicates an on-going degradation of the applied fixatives.The extensive deterioration of the surfaces is also due to the widespread presence of salts, such as chloride, nitrate and sulphate clearly identified by XRD measurements.The obtained results give a comprehensive overview on the employed painting technique and its state of preservation and on the causes of the painting deterioration. Therefore, they are a fundamental tool to develop durable and compatible materials and methodologies for a future conservation strategy of this site.  相似文献   

20.
Ceramic samples made with a mixture of 70% ball clay and 30% quartz sand were moulded and then fired at 900 °C in an electric kiln. Samples were then treated with different products and analyses and tests were performed to evaluate the physical changes induced by the application of these products and their effects on the quality of the ceramics. A petrographic study indicated that the ceramics were composed of quartz, small amounts of mullite and sanidine and traces of hematite. Mineral clays (i.e. kaolinite) disappeared during firing. Two consolidating products (Paraloid B72 and Tegovakon V) and one water repellent (Silo 111) were applied to samples by capillarity, and physical changes (colour, water flow, porosity and pore size distribution) were measured. Finally, we carried out salt crystallization tests in order to determine which product improved the quality of the ceramics. Treated samples registered a decrease in porosity and a general increase in pore size. The application of Silo 111 drastically reduced water absorption by immersion and by capillarity. This product was also responsible for a decrease in pore interconnection. Samples treated with Tegovakon V performed better in terms of their overall hydric behaviour. Silo 111 was the only product that did not modify the colour of samples when compared with untreated ones, and after accelerated aging tests, samples treated with this product hindered the absorption of saline solution into ceramic pores and prevented their decay. Paraloid B72 did not improve any of the properties of the ceramics.  相似文献   

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