Plaster Composites Research Articles

X-ray computed tomography (XCT) and chemical analysis (EDX and XRF) used in conjunction for cultural conservation: the case of the earliest scientifically described dinosaur Megalosaurus bucklandii

This paper demonstrates the combined use of X-ray computed tomography (XCT), energy dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) to evaluate the conservational history of the dentary (lower jaw) of Megalosaurus bucklandii Mantell, 1827, the first scientifically described dinosaur. Previous analysis using XCT revealed that the specimen had undergone at least two phases of repair using two different kinds of plaster, although their composition remained undetermined. Additional chemical analysis using EDX and XRF has allowed the determination of the composition of these unidentified plasters, revealing that they are of similar composition, composed dominantly of ‘plaster of Paris’ mixed with quartz sand and calcite, potentially from the matrix material of the Stonesfield Slate, with the trace presence of chlorine. One of the plasters unusually contains the pigment minium (naturally occurring lead tetroxide; Pb22+Pb4+O4) whilst the other seems to have an additional coating of barium hydroxide (Ba(OH)2), indicating that these likely represent two separate stages of repair. The potential of this combined approach for evaluating problematic museum objects for conservation is further discussed as is its usage in cultural heritage today.

Fire Behaviors of the Geomaterial-Based Composite Plaster Coated Building Thermal Isolation Plates

Abstract Thermal insulation in buildings has been a problem for mankind throughout history. New materials have always been used in this context, and every new material has negative aspects such as environmental, economic and engineering. Although the building exterior insulation materials produced in recent years have made significant progress in terms of thermal comfort, but those with superior properties in resistance to fire are very limited. In this study, considering the environmental sensitivity, the plasters produced from the sands of arenitized granite, micaschist, pumice and expanded perlite rocks and their combinations were applied on expanded polystyrene (EPS), extruded polystyrene (XPS) foams and mineral wool for investigating the fire behaviors of each material. As a result of fire tests, it was observed that the most positive values were gained from micaschist based external isolation board, whereas the board obtained from arenitized granite gave the most negative values. With the combination of natural and environmentally friendly materials such as micaschist, perlite and pumice, on a fire resistant insulation material such as mineral wool, a highly fire resistant, environmentally sensitive and economical insulation material can be produced.

Dekoracja malarska na fasadzie kamienicy przy ul. Długiej 1 w Gdańsku – problematyka technologiczno-konserwatorska

The article focuses on the techno-conservation issues of the facade of the residential tenement (kamienica) at ul. Dluga 1 in Gdansk. Its decorations are discussed in a broader context of the finishing works on Dluga and Dlugi Targ streets carried out during the post-war reconstruction of the Gdansk Main City borough. The techniques and technologies of these decorations are examined in the frame of their historical context. The state of preservation of the tenement’s facade is presented, alongside the key damaging factors. The following part presents the initial research results from the tenement’s painting decorations: a plaster composition analysis, a binder type specification and a pigment identification.

Plaster composites modified morphology with enhanced compressive strength and water resistance characteristics

Due increasing attention for non-conventional building materials, modified gypsum plaster composites were studied to assess their water resistance when blended with different additives and their effect on the strength properties. The plaster-composites were formed by dry mixing of fine or ultrafine sand, silica fume, silica gel, rice husk, slag, calcium carbonate or polyvinyl acetate (PVA). Their phase composition was investigated using FTIR and XRD with crystallite size data to be correlated with their microstructure morphologies as elucidated by SEM for the air- and water-cured samples.Results clarified that the morphology and some grain dimensions of set plaster composites have changed leading to improve their compressive strength and water resistance. The set plaster grain dimensions altered from long acicular crystals to short compact thin one. Composites with almost all additives reveal resistance to water whereas silica gel showed lower effect, due to its higher affinity to humidity. The compressive strength and softening coefficient of the water-cured plaster-slag composite increased by about 30% compared with air-cured blank sample due to the hydration of slag in gypsum composite matrix. Either calcium carbonate or PVA usage (3 wt%) in gypsum composites improved the compressive strength by about 14 and 19% of water cured samples, respectively. The synthesized plaster composites are promising building units for various applications when lightweight, high porosity, water resistant building units are needed.

The green grass was never green: How spectroscopic techniques should have assisted restoration works

This paper presents the results of a multidisciplinary research based on the use of different diagnostic techniques for the study of wall paintings that belong to the late Gothic period and are preserved in the church of Saint Stephen in Ribera de Valderejo (Álava, Basque Country). Portable Raman and X-ray fluorescence spectroscopy measurements carried out in-situ allowed to characterize the plaster composition, the colour palette used by the artists and the materials employed during the restoration works in recent times. The analyses were focused especially on some areas that appear unusually grey. Apparently, the results obtained by both techniques seem to be contradictory and it was necessary to perform a selective sampling in some areas of interest which were analyzed in the laboratory. Raman spectroscopy and scanning electron microscope, coupled with energy dispersive X spectroscopy, applied on the cross-section of micro samples, made possible to clarify some important issues, showing the inadequacy of the restoration works carried out in previous years and the presence of a potentially dangerous material too (magnesium arsenate), whose use was not documented. The results demonstrated the importance of using diagnostic tools for the identification of the materials belonging to Cultural Heritage, especially before restoration works in order to choose the most appropriate methodology and to respect the original appearance of the paintings.

Improving Electromagnetic Shielding Ability of Plaster‐Based Composites by Addition of Carbon Fibers

The size of electromagnetic shielding in plaster composites by the means of different volume fractions of carbon fibers was studied in this paper. Conventional types of plaster, which are commonly used in industry, that is, cement, lime, gypsum, and lime cement (Thermo UM), were the base materials of the created composites. The fundamental idea of improving the electromagnetic shielding properties was verified based on a numerical simulation conducted by means of electromagnetic module in Comsol Multiphysics. The carbon microfibers with the above‐critical length of 8 mm were added as the reinforcing and simultaneously shielding element into the plaster samples. From the viewpoint of the mechanical properties, fibers shorter than the critical length do not provide sufficient reinforcement. The samples were created at three different volume fractions of the dispersion and one without any reinforcement for the possibilities of their mutual comparison. The results of the carried measurement show that the electromagnetic shielding in the plaster composite grows with the increase of fiber content within the tested ratio proportionately. Also, the dependency of shielding ability on the inner material moisture has been studied. Any measureable influence of the moisture content on to the total shielding effect has not been found. Only in the lime plaster reinforced with fibers, the increased moisture could significantly decrease the shielding effect.

Chemical and pharmaco-technological evaluation of Adjara region peat peloids

“Peloids” is an internationally recognized name of all kind medical muds. They are natural mixture of inorganic and organic materials and performs homogenous, finely dispersed mass with definite physical and chemical properties The effectiveness of peloids is due to high content of biologically active substances. High content of organic substances in peloids, such as chemically and biologically active organic carbon compounds formed by long-term chemical and microbiological processes, provides their application prospects in clinical practice. The objective of the research was evaluation chemical and pharmacotechnological properties of Adjara region Peat Peloids. The following tasks were to be solved to achieve the goal: Study chemical properties of Adjara region Peat Peloids; Determination spectrum of organic and inorganic substances; Formulation of nanocomposite containing sphagnum peat peloids; Formulation composition and development preparation technology of topical dosage form, plaster, containing nanocomposite of sphagnum peat peloids; Study antiinflammatory and antibacterial activity of peat peloids; The materilas of the research: sphagnum peat peloids of different ages (Ispani, Anaklia, Chirukhi, Peranga, Churia). Research strategy was to held experiments gradually from simple to complicated. Technological and biologic methods were used to solve research tasks. Research was held using modern instrumental methods of analysis&apparatus (UV spectrophotometer, Scanning Electron Microscopy, X ray fluorescence, Centrifuge, Dry oven, Ultraturax, AFM, XRD). It is estimated that Kolkheti sphagnum peat peloids contain a wide range of organic substances: humic acids, amino acids, fatty acids, carbohydrates and others. As a result of the research composition, design and preparation technology of plaster containing nanoconstructed system of sphagnum peat peloids is determined. Based on the research data Isapani sphagnum peat peloids and formulated dosage form (plaster) obtained anti-inflammatory action. Based on serial dilution (macro) method antibacterial activity of high concentration (1:1) sphagnum peat peloids (Ispani) was established.

Improvement of the Acoustic Attenuation of Plaster Composites by the Addition of Short‐Fibre Reinforcement

Noise attenuation is a key contemporary issue associated with the protection of human health. In this study, the possibilities of affecting acoustic properties of plaster composites by the addition of short‐fibre reinforcement are described. The improvement of attenuation abilities was first verified using a simple numerical model with a pure plaster followed by using a reinforced plaster. The model results revealed a mutual correlation between the fibre ratio and dissipated acoustic energy. Hence, typical plasters used in the building industry (e.g., plaster, lime cement, and cement) are used as the base materials of the tested composites. The reinforcing dispersion in the form of short fibres (basalt and glass) with a defined length was selected after evidence from previously reported studies and after the comparison of some other fibres with respect to the trade‐off between the rendered mechanical properties and cost. Transfer functions of the tested samples were measured using an impedance tube with two microphones, followed by the calculation of the total acoustic absorption. On the other hand, cement and plaster materials exhibited a low damping ability, and the absorption could be considerably increased by the addition of fibres, especially in the area around 1 kHz. In contrast, the UM plaster exhibited good damping properties even without the dispersion, and the addition of improper fibres such as glass ones possibly worsened the properties. The acoustic attenuation of the plaster composites can be improved by the appropriate combination of the base material and fibre dispersion. However, it is not possible to generalise this improvement for all possible combinations.

Computer modelling of fire resistant solutions for structures in high-rise buildings with using of new fire-retardant materials

The article describes possibilities of computer modeling of fire resistance for structures in high-rise buildings, which include new fire-resistant plaster compositions. As an example of program complex, “Sofistik” (Germany) was chosen for the calculation of reinforced concrete structures of tier buildings. The characteristics of fire protection compounds and their regulation, which are usually used, also are shown. According to the new code “Highrise buildings and complexes. Fire safety requirements”, limits of fire resistance for walls of not less than 240 minutes. Skyscraper “Lakhta center” with a height of 462 m and limits of fire resistance of load-bearing reinforced concrete structures 180 and 240 minutes is built up in Russia. The article investigates the means of fire protection in the business center. Moreover, modern form of cladding in Mada Residences building (Dubai, UAE) is concerned to make some conclusions about future fire resistant solutions.

Possibilities to improve electromagnetic shielding of plaster composites adding carbon fibers

This paper studies size of electromagnetic shielding in plaster composites, using different volume fractions of carbon fibers. Conventional types of plaster, which are normally used in construction (i.e. cement, lime, gypsum and lime cement) were the main parts of the created composites The carbon microfibers with a length of 8 mm were added as reinforcing and simultaneously shielding element into plaster samples. The tested samples were created at three different volume fractions of the fibres and also into the base plaster for possibilities of their comparison. The results of carried measurement show that the electromagnetic shielding in the plaster composite grows with increasing fiber content in the tested ratio almost linearly.

EXPERIENCE OF USING THE MONTE-CARLO METHOD IN DETERMINING OPTIMAL PLASTER COMPOSITIONS WITH IMPROVED STRENGTH PROPERTIES

Considering that modern building materials impose increasing performance requirements, it is necessary to expand the range of building materials and improve their multicomponent composition. The effects of polymer and porous components (expanded perlite sand and carbonate filler – limestone-shell rock) in cement-lime light plaster on the physico-mechanical properties of the mixtures under equal workability conditions of mixtures are analyzed based on experimental-statistical modeling. The results of the physico-mechanical and operational experiments confirm the rationality of using porous fillers and additives to improve certain specific properties of the final product. The so-called Monte-Carlo method is implemented for determining an optimal composition of multicomponent cement-lime light plaster, based on multivariate statistical modeling and iterative random scanning of property fields. According to the results of the computational experiment, a composition that reduces the number of expensive mixture components and improves the physical and mechanical characteristics of the resulting composition is selected.

Study of the acoustic attenuation in plaster composites in dependency on added fiber reinforcement

The current trend, with regards to the cost and energy savings, is to combine properties of basic materials and try to obtain so called synergic effect with that we could get significant amplification of their individual properties. The aim of this article is to assess whether this required improvement of the physical properties occurs also for fiber-reinforced construction materials, whose study has been the author work devoted for a long time. This work is focused on assessment of changes in the acoustic attenuation of the basic plaster composites with addition of some high strength fiber reinforcement. The chosen plasters materials are commonly used in building constructions (gypsum, lime-cement, cement). Into those materials that in our case has become the matrix, some basalt and glass fiber dispersion of length 8.5 and 12 mm have been added. An impedance tube was used to the test of materials acoustic absorption. The results show the very good acoustic absorption for all of the tested samples regardless on the ratio of used reinforcement.

Modification of plaster compositions for building facade finishing with nanotechnological materials

Analysis of the modern state of the facade system market was conducted, major deficiencies and basic requirements to facade surfaces and materials were identified. It was established that high quality of the surfaces is achieved through stability of the composition and properties of the raw materials used, and fillers – their quantitative content and dispersity – play a particularly important role. The problem of the optimal filling of plaster compositions, labor intensity and low profitability of natural filler production was raised A solution was suggested: expand the nomenclature of fillers for plaster compositions of the new generation, apply nanotechnological raw materials, in particular, carbonate sludge – the product of reactant treatment of waste water from thermal power plants and carbonate siliceous product – flue dust from asphalt concrete plants. Both wastes are depositable anthropogenic sources of environmental pollution. Formulations of facade compositions, modified with nanotechnological mineral fillers with high properties (adhesive strength, compressive strength, cold resistance), confirmed by a number of Russian patents, have been developed.

Study and evaluation of nano-structured cellulose fibers as additive for restoration of historical mortars and plasters

UPM bio-fibrils are nano-structured cellulose fibers (nano-fibrils) produced by UPM Kymmene-Corporation, a Finnish company. This paper reports a preliminary study about nano-fibrils to determine their possible use for restoration of historical mortars and plasters.The aim of this study is to investigate the behavior of some mixtures added with nano-fibrils in their properties for conservative purposes. These mixtures reproduce the composition of historical mortars and plasters, made of natural hydraulic lime (NHL 3.5) and river sand. After 28 days of hardening, the properties of specimens with nano-fibrils were compared with untreated one to understand how nano-fibrils interact with inorganic matrix. They influenced the mortar properties in different ways. For example, mechanical tests showed a decrease of flexural and compressive strength as the percentage of nano-fibrils increased. Nevertheless, capillary absorption tests proved that the addition of nano-fibrils was beneficial to the mortar because the final amount of absorbed water was lower for the samples with a higher percentage of nano-fibrils.

HISTORICAL PLASTER COMPOSITION DETECTION USING REFLECTANCE SPECTROSCOPY

Reflectance spectroscopy is a non-invasive method that is based on the fact that a specificobject/material provides various reflectances in different wavelengths across the spectral range. Itcan provide unique information regarding the material composition of the object of interest and hasbeen used in many fields in recent years. Determining composition of historical plaster is veryimportant when defining its individual components and possibly place of origin or even its age. Thisinformation can be a key issue for its future repairs that are desired to be done as similar to theoriginal method as possible.For a precise reflectance spectroscopy material detection, a fine spectral library is needed.Special mathematical methods are used for comparison of measured spectral curve with individualspectral curves stored in the used spectral library. The spectral analysis then shows similarity ofthe measured curve with the reference ones.This paper introduces results of the new plaster composition spectral library created byDepartment of Geomatics, Faculty of Civil Engineering, Czech Technical University in Praguewithin the Czech Ministry of Culture Project (DF13P01OVV002). This spectral library has beentested on two historical plaster samples.

Istraživanje sastava i svojstava srednjovjekovne žbuke u crkvi sv. Marije kod Lokve te komparativna ispitivanja komercijalnih materijala za injektiranje

Istraživanje sastava i svojstava srednjovjekovne žbuke u crkvi sv. Marije kod Lokve te komparativna ispitivanja komercijalnih materijala za injektiranje

Composition and Microstructure of Plasters in Convent of the Želiv Monastery (Czech Republic)

The paper deals with analyses of composition and structure of historic plasters from the convent building of the Želiv Monastery (Czech Republic). Composition and microstructure of plaster samples taken from the historic object have been assessed using both traditional and advanced analytical methods. The following techniques have been used for the assessment of binders and fine aggregates in plasters: optical microscopy of thin sections, mineralogical and petrographic analysis of separated components, infrared spectroscopy, and thermal analysis. Presented results show significant differences in character of the studied materials of varying age and demonstrate the effectiveness of the taken analytical approach.

Thermal behavior of a hybrid PCM/plaster: A numerical and experimental investigation

The Phase Change Material (PCM) integrated in building envelope can decrease the energy requirement for maintaining thermal comfort by enhancing the thermal energy storage of the wall and the roof. This study deals with numerical and experimental study of the thermal behavior of new plaster composite containing a microencapsulated PCM that can be embedded as a component in passive solar walls. Experimental measurement was performed by using a transient guarded hot plates method based on heat flux and temperature measurements. As for numerical simulation, it is based on the enthalpy method. Such a simulation was performed using a finite volume method (FVM). Then, a comparison between the two approaches is performed. It is found that our numerical findings match the experimental results. Interestingly, the results demonstrate the suitability of incorporating microencapsulated PCM into plaster.Based on the obtained results, it may be stated that the thermal storage capacity of the plaster is greatly enhanced.

Fire and Explosion Protection of High-Rise Buildings by Means of Plaster Compositions

The article describes the aspects of fire protection of high-rise buildings. Various methods of protection of unique buildings from fire and explosion in the world practice were considered. For example, using the innovative fire-resistant materials on load-bearing structures, their characteristics and rationing, progressive collapse. The comparative analysis of various types of fire-resistant plaster by such parameters as the chemical composition, fire resistance, durability, density, thickness of the layer was made. Perspectives of development of fireproof plaster compositions were projected.

An analytical and geoarchaeological approach on earthen plaster of 2nd century BCE Karle caves of Western Deccan, India

This study documents a holistic approach, combining mineralogical, geochemical and textural data to characterize the decorative earthen plaster of the 2nd century BCE. Buddhist rock cut caves of Karle in Western India. The analytical examination was carried out by the use of a petrological microscope, Laser particle size analysis, thin section analysis, XRF (X Ray fluorescence), XRD (X Ray Diffraction), FTIR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscope) and Raman spectroscopy in addition to the monitoring of environmental parameters. The results indicate that the local clayey soil, which is abundantly available in the high rain fed western coastal areas, was utilized for the earliest earthen plaster works. The characteristics of the clay seem to have been modified by mixing calcite and an organic adhesive. Rounded sub-angular aggregates derived from disintegration of basaltic rock and rice husk were added to influence shrinkage properties of the plaster. In addition to a better understanding of the technology and composition of ancient India's early earthen plasterworks, scientific data from the analysis was used to plan the composition of restoration plaster.