Plaster Layer Research Articles

Disappearance of the Limestone Architectural Heritage in Central Poland - Trends and Challenges

Koło Basin is a geographical region located in central Poland, where in the period from the mid-XIX century until the late of 1960s the traditional rural construction had been developing architectural features of a unique character. The structures in that area were not being constructed using wood, which was the most common construction material used throughout the Polish lowlands, but limestone, mined at small local quarries. Their emergence is a result of a specific terrain of the discussed area, where in the vicinity of villages Rożniatów and Czepów, as well as the little town of Poddębice, a layer of Cretaceous sedimentary rocks reaches to the surface. An estimated number of 3,000 structures in the region was erected using this material. These include houses, homesteads, barns, churches, manors, mills and other rural buildings. Research conducted by the authors between 2011-2017 revealed that a little over 2,300 of these structures still exist. In the recent times, the speed of removal of these buildings, which are such a characteristic feature of the region’s cultural landscape, rapidly increased. There are at least a few causes of this phenomenon. The depopulation of the rural areas results in abandoning of the farms, which thereafter soon become derelict and devastated. Most of the residential structures made of limestone in the past centuries does not meet the current utility standards. Therefore, they are frequently taken apart, and being replaced by new structures made out of modern construction materials and integrating universal design projects. More frequently as well, the owners of such structures are upgrading and expanding the existing construction, having the existing limestone elements covered with layers of thermo-isolation and plaster. These changes involve also farm utility structures for agricultural production. Since Poland’s accession to the European Union, the rural areas of the country begun a definite expansion, but also a change in its profile and scale. As one of the side-effects of modernization of farmsteads, which were to increase their profitability and competitiveness, old structures are being abandoned and demolished. The civilization growth in Koło Basin and its surroundings results in the improving of its populations’ living and working conditions is definitely a positive development. It’d be beneficial however that it proceeds in a more harmonious and balanced manner, preserving the unique cultural heritage of the region. In authors’ opinion the actions which had been taken by the local authorities so far towards the protection and the preservation of these assets of cultural heritage for generations to come do not guarantee success of the undertaking. There is a necessity for forming and a subsequent firm execution a complex plan for protection of the limestone structures in the region. Authors point to the fact that the rural limestone architecture existing in Koło Basin is unique in the scale in this part of Europe.

Grip Fixing Instead of Adhesive - Exterior Insulation Finishing Systems (EIFS) as a Sorted Recyclable Façade System with Reclosable Fastener Fixation

The paper describes the project facade4zeroWaste which includes the development, architectural design relevance, grants of patents, results of pre-certification testing’s and the product publication in the time frame from 2009 till 2017. Aim of the research project facade4zeroWaste was the idea of a recyclable facade insulation system that can easily be dismantled after its lifetime and reused thanks to an innovative grip fixing system consisting of mushroom-shaped heads and loops - Grip fixing instead of adhesive. The project won numerous prices and awards like the EQAR - Recycling Prize 2015 or the Innovation Award for Architecture and Building 2017. The project is a contract research project tasked by Sto SE & Co. KGaA, Germany and Sto GesmbH, Austria. The façade system was presented to the public in January 2017 as the product Sto Systain R (R = render: seamless plaster layer surface) on the building fair BAU 2017 in Munich. *

Integrating Non-Destructive Testing, Laser Scanning, and Numerical Modeling for Damage Assessment: The Room of the Elements

For preservation efforts and stability assessment of historic structures it is imperative to understand the extent of existing damages and possible modes for how they could have occurred. The aim of this work is to illustrate the importance of integrating documentation, non-destructive testing, and numerical modeling for damage assessment of heritage structures. In particular, this work explores the synthesis of these techniques on a plastered masonry wall in Palazzo Vecchio. Laser scanning was used to capture the geometry of the wall while terrestrial photogrammetry and high-resolution images were used to document the magnitude of cracking in the plaster layer. High resolution thermal images were used to document the distribution of stones and additional cracks not visible through the plaster layer. The results of documentation and non-destructive testing were used to generate an as-built model for structural analysis. Finite distinct element modeling was used to simulate the response of the wall to a series of loading conditions. By comparing the results of simulation to existing crack patterns, theories for how the damage occurred were generated.

Defects of sandwich walls

Thermal protection of spaces contributes to the fact that sandwich walls dominate in heated buildings. Their design requires knowledge regarding the operating principles of sandwich systems. Without knowledge of these principles, numerous mistakes are made. The study describes mistakes encountered made during erection of triple-layer and double-layer walls. The effects of a shortage and excess of connecting pieces in triple-layer walls are presented. For double-layer walls, the necessity of insulation expansion joints is shown using an example. Using the tests, it is proven that the strength of the adhesive layer created during the autumn/winter transitional period is very heavily decreased, even more than 50%, which in connection with over-stiffened anchors leads to very numerous cracks, to the destruction of the external layer of insulation. High diffusion resistance of the external layer of insulation with low diffusion resistance (mineral wool) also leads to the destruction of the adhesive & plaster layer. Furthermore, the considerable significance of the use of good quality reinforcing, anchoring, gluing and painting & plastering materials was emphasized.

Stucco repair method for enclosing brick walls

During the operation of buildings, plaster coatings of the external and internal enclosing surfaces of brick walls are subjected to various destructive influences. Existing methods of repairing plaster coatings do not fully ensure strong adhesion of the material of the repair layer of plaster to the surface of the repaired brick wall structure. In addition, these methods can only get rid of damage but do not improve the operational properties of the plaster layer of the repaired structure. Thus, the urgent problem is the development of an effective method of repairing plaster coatings on the surfaces of brick walls, due to which it will become possible to ensure the monolithic of the repaired plastering structure. In order to address the shortcomings of the existing plaster coating repair techniques on the surfaces of the brick walls and finding ways to improve it, by the authors investigated the possibility and the expediency of performing the repair of additional process steps. A feature of this repair method is the use of preheated plaster mortar, flexible plaster molding, as well as compaction of the stucco mortar in the contact area with the repaired brick wall structure with a deep plate compactor. The test results of samples of plaster coatings manufactured by the proposed method showed the high efficiency and feasibility of using this method for repairs on the external and internal surfaces of walling of brick walls and are mentioned in the patent for the invention of the Russian Federation. The performance characteristics of the plaster are significantly increased as a result of the application of this method, and, consequently, the service life of the plaster coating is increased several times.

Twenty Years of Experience in the Use of Facade Insulation with a Thin Plaster Layer in the Republic of Bashkortostan

Twenty Years of Experience in the Use of Facade Insulation with a Thin Plaster Layer in the Republic of Bashkortostan

Microenvironmental features drive the distribution of lichens in the House of the Ancient Hunt, Pompeii, Italy

On the stone cultural heritage, the influence of architecture-related microenvironmental features on lichen diversity, abundance and consequent threats for conservation has been still poorly characterized to support management plans. Such relationships were here investigated on the vertical surfaces of the House of the Ancient Hunt in Pompeii, archaeological site in S-Italy where the variability of lichen saxicolous communities has been still completely neglected despite their widespread occurrence. Lichen colonization in semiconfined rooms was sporadic and limited to Dirina massiliensis, while a remarkable turnover of six communities, encompassing 22 species, characterized mortar, painted and plastered surfaces in outdoor environments, with local covers up to 80%. Microscopic and spectroscopic analyses displayed the deteriogenic potential of three dominant species, due to hyphal penetration within paint and plaster layers (Verrucaria macrostoma) and the release of oxalic acid and/or secondary metabolites with acidic and chelating functions (D. massiliensis, Lepraria lobificans). A higher vertical distance of surfaces from the ground and a larger room dimension were the main conditional factors related to a higher lichen abundance and the distribution of the different communities. Such knowledge on architecture-related microenvironmental features driving lichen distribution and biodeterioration threats may contribute to address restoration priorities and conservation strategies.

Severe Burn Injury in a Swine Model for Clinical Dressing Assessment.

Wound healing is a dynamic repair process and is the most complex biological process in human life. In response to burn injury, alterations in biological pathways impair the inflammation response, resulting in delayed wound healing. Impaired wound healing frequently occurs in patients with diabetes leading to unfavorable outcomes such as amputation. Hence, dressings having beneficial effect in promoting burn wound repair are needed. However, studies on burn wound treatment are limited due to lack of proper animal models. Our previous study demonstrated wound-healing performance in rat and swine models using a minimally invasive surgical technique. This study aimed to demonstrate a swine model of severe burn injury that eliminates wound contraction and more closely approximates the human processes of re-epithelialization and new tissue formation. This protocol provides a detailed procedure for creating consistent burn wounds and examining the wound-healing performance under the treatment of an experimental dressing in a swine model. Six burn wounds were created symmetrically on the dorsum, which were covered with a clinical dressing composed of four layers: an inner contact layer of experimental materials, an inner intermediate layer of waterproof film, an outer intermediate layer of gauze, and an outer layer of adhesive plaster. Upon the completion of experiments, wound closure, wound area, and Vancouver Scar Scale score were examined. The samples of skin resected from each animal post-sacrifice were histologically prepared and stained using hematoxylin and eosin staining. Antibacterial activity of each dressing in the context of wound healing was also examined. The application of the clinical dressing to the wounds in swine model mimics the biological processes of human wound healing with respect to the processes of epithelialization, cellular proliferation, and angiogenesis. Therefore, this swine model provides an easy-to-learn, cost-effective, and robust method to assess the effect of clinical dressings in severe burn injury.

Laboratory analyses and numerical simulation for sound absorption of plasters in historical buildings

Abstract During the restoration of historical buildings, it is very important for the maintenance of the authenticity of the building that decisions related to the selection of materials and the plaster mortar mixtures, determined through plaster analyses, are in accordance with those of the historical structure. In restoration of the historical buildings, there are also some important parameters related with interior room acoustics such as propagating sound properly, ensuring speech intelligibility, preventing from undesirable interior noise and maintaining of auditory comfort conditions. The present study investigates how the sound-absorption coefficient of existing plaster layers can be increased and describes the means of ensuring the newly applied plaster layers are in accordance with the historical structure. Within the study, three different plaster mixtures containing three different type of binder, with plaster layers of 3 cm, 6 cm, 9 cm and 12 cm thickness were produced with each mixture type. The sound-absorption coefficient tests were carried out according to mixtures type and plaster layer thickness. The sound absorption coefficients were modeled using MATLAB software for different plaster thicknesses based on the results obtained from the sound-absorption coefficient measurements. In following stage, to show the effect of the measurement results of the sound-absorption coefficient within the place, a historical place was selected and reverberation time analyses were carried out in the direction of the measurement results. In this research, it is demonstrated that the sound absorption can be increased by means of increasing plaster layer thickness and changing mortar mixture types. It is concluded that the sound absorption research for historical buildings systematically carried out in order to show the role of importance sound absorption material selection in accordance with historical plaster analysis in restoration process.

Restoration effects on experimental dynamic characteristics of masonry stone minarets

Masonry minarets are sensitive to wind and earthquake forces due to their slenderness and supporting structural system. They are restored in order to safely transfer to future generations. This paper investigates the restoration effects on the dynamic characteristics of masonry stone minarets using ambient vibrations tests. Three historical masonry stone minarets restored by the Regional Directorate of Foundation in Trabzon, Turkey are selected for this purpose. Restorations works such as re-pointing of joints, renewing spoiled stones, scraping cement-based plaster layer coating, rebuilding upper part wall of the minaret balcony, wall surface cleaning and renewing wooden cone were implemented in the selected three minarets. The experimental dynamic characteristics of the selected minarets before and after restoration are determined by Operational Modal Analyses Method using the ambient vibrations. The natural frequency, mode shapes and damping ratios obtained before and after restorations are compared with each other. It has been shown that the dynamic characteristics of the three minarets are positively and negatively affected depending on the restoration works.

The laboratory analyses for the plasters prepared with river sand aggregate and hydraulic lime binder

In historical building restorations, the selection of mortar mixture type should be determined in accordance with particularrequirements of the historical buildings. In this study, it has been examined that how the sound absorption coefficients of plaster layers can be increased in ways that are compatible with the historical structures. In the scope of lab analyses, mixtures produced with river sand aggregate and hydraulic lime binder were examined. Material properties of samples were investigated by means of the experimental analyses which can be listed as sound absorption, open porosity, capillarity of water absorption, flexural and compressive strength. The effects of the binder ratio and aggregate particle size range in mortar mixtures were investigated in order to increase the sound absorption in the plaster layer. Moreover, the effects of polypropylene fiber, flax fiber and crumb rubber additive were investigated as well. After the measurement results are obtained, the outcomes of the experiments were discussed. In this research, it is demonstrated that the sound absorption can be increased by the content of the mixture. Especially, it is observed that the reduction of the binder ratio in the mixture may increase sound absorption and the use of very fine aggregates in the mixture can adversely affect sound absorption. In brief, a systematic research was carried out in order to increase sound absorption coefficients in accordance with the content of the plasters used on historical buildings.

Effects of thermal insulation on the airborne sound insulation of AAC masonry walls

AbstractInsulation systems change the acoustic properties of solid walls. A thermal insulation can have positive or negative effects on the airborne sound insulation. The behavior of heavier walls (e.g., calcium silicate bricks or clay bricks) is very well documented. The acoustic behavior of autoclaved aerated concrete (AAC) walls with thermal insulation has not yet been similarly analyzed. Therefore, some tests on the acoustic behavior of AAC walls with thermal insulation were conducted. During the test, different insulation systems were attached to an AAC wall (expanded polystyrene (EPS), elasticized expanded polystyrene (eEPS), phenolic insulation (FP)). The mass of the outer plaster was also variated. Furthermore, an AAC cavity wall was tested. The tests show that the airborne sound reduction index of a monolithic AAC masonry wall can be considerably improved if the appropriate thermal insulation is selected. The use of an elasticized polystyrene insulation leads to an improvement of the sound reduction index between 3 and 5 dB. An additional plaster layer has further positive effects with an overall improvement of up to 9 dB. The tests also proved that a polystyrene insulation with a thickness of 16 cm does not lead to a decline of the airborne sound reduction index.

Unraveling the materials and techniques of post-Byzantine wall paintings: Is there a sole pictorial phase at the catholicon of Stomion, Central Greece?

Saint Demetrius of Stomion is a historical monastery placed in the geographical area of Larissa town, Greece, with a remarkable presence from its founding until nowadays. The monastery's present catholicon (main church) has been dated in the 16th century and its surviving wall paintings were constructed in 1758. In addition to the characterization of the materials applied, the purpose of this study is to determine the existence of a sole pictorial phase, that of the mid-18th century, or the occurrence of overpaintings. Additionally, the present study aims to begin the establishment of the documentation of materials and techniques of the late post-Byzantine iconographic guilds, which acted in Central and Northern Greece. The collected samples were analyzed by means of microscopic, spectroscopic and thermogravimetric methods. The use of fresco technique is implied by the major participation of calcium carbonate in all of the painting layers, its main contribution in the plaster layers and the microstratigraphic analysis of the samples' cross-sections, while the scarce and local presence of a proteinaceous material implies the limited use of egg-tempera technique for the highlights. The pigment analysis shows that mostly traditional pigments were used, including cinnabar, ferrous pigments (ochre, sienna, umber), minium, Naples yellow, massicot/litharge, green earth (celadonite), malachite, carbon and bone black, calcite, kaolinite and lead white. The absence of modern pigments, the consistency of all samples regarding microstratigraphy and applied materials, and the lack of the extensive use of an organic medium, strongly suggest the lack of overpaintings.

Mineralogical, petrographic and physical-mechanical study of Roman construction materials from the Maritime Theatre of Hadrian's Villa (Rome, Italy)

This paper presents the study of various Roman materials used in the construction of the Maritime Theatre, one of the main buildings in the Hadrian’s Villa complex, a designated UNESCO World Heritage Site located in Tivoli (Rome, Italy), dating to the first half of the II century A.D. The plaster layers (arriccio and intonachino) and overlying original Roman paintings that form the concave wall of the portico as well as some bedding mortars of the pyramidal stone elements (i.e. cubilia) of the circular masonry have been studied in particular. In addition, the acid volcanic rocks of the cubilia have been investigated, aiming to understand their state of alteration and geological origin.By mineralogical-petrographic microscopy (OM), diffractometry (XRPD), Raman spectroscopy, Point Load Tests (PLT), helium pycnometry, and particle size analysis, the composition and granulometric distribution of the aggregate, type and characteristics of the binder, and various physical-mechanical properties (density, porosity, water absorption, imbibition and saturation indices, mechanical resistance) of mortars and stones were defined. In addition, through digital image analysis of thin sections, the binder/aggregate ratio and some geometric characteristics of the aggregates (e.g. circularity) were determined.The research aims to improve the knowledge of the constructive technologies of the Maritime Theatre through the analysis of its materials.

Vibrometry Assessment of the External Thermal Composite Insulation Systems Influence on the Façade Airborne Sound Insulation

This paper verifies the impact of the use of an external thermal composite system (ETICS) on air-borne sound insulation. For optimum accuracy over a wide frequency range, classical microphone based transmission measurements are combined with accelerometer based vibrometry measurements. Consistency is found between structural resonance frequencies and bending wave velocity dispersion curves determined by vibrometry on the one hand and spectral features of the sound reduction index, the ETICS mass-spring-mass resonance induced dip in the acoustic insulation spectrum, and the coincidence induced dip on the other hand. Scanning vibrometry proves to be an effective tool for structural assessment in the design phase of ETICS systems. The measured spectra are obtained with high resolution in wide frequency range, and yield sound insulation values are not affected by the room acoustic features of the laboratory transmission rooms. The complementarity between the microphone and accelerometer based results allows assessing the effect of ETICS on the sound insulation spectrum in an extended frequency range from 20 Hz to 10 kHz. The modified engineering ΔR prediction model for frequency range up to coincidence frequency of external plaster layer is recommended. Values for the sound reduction index obtained by a modified prediction method are consistent with the measured data.

Study of the Impact of Microstructure and Sorption Properties of the Renovation Plasters on the Wall Drying Rate

The purpose of the study was to determine the relationship between the microstructure and sorption properties of plasters and the drying rate of walls made of sandstone, silicate bricks, ceramic Gothic and Cadinen bricks. The porosity of plasters was 30%, 40% and 50%, and they differed in water sorption. The studies were carried out with one and two layers of plaster. It was demonstrated that the properties of the renovation plasters influence their drying rate. Plasters with a polymodal distribution of pore size and porosity of 50% shortened the wall drying rate, while monomodal distribution and hydrophobic plasters extended the wall drying rate.

Low-emissivity coating coupled with aerogel-based plaster for walls' internal surface application in buildings: Energy saving potential based on thermal comfort assessment

Building envelope reflective finishing can play a major role in the energy saving of buildings. Extensive research demonstrated the influence of such a finishing on the external surface of horizontal and vertical walls; however, research on low-emissivity (low-e) finishing at the interior surface of vertical envelopes is hardly found in the literature. Accordingly, this study starts with a state-of-the-art on low-e applications in buildings. Dynamic simulations are then carried out to investigate the thermal and hygro-thermal behavior of envelopes with interior surface low-e coating, during heating and cooling season in Lyon, France. A new methodology to simulate the operative temperature of the indoor environment, considering the emissivity of the indoor surfaces, is proposed. Results showed that the energy-saving potential of low-emissivity finishing is major when applied to low/non-insulated buildings, particularly when considering thermal comfort. A foreseen application is to couple this technology with a system that controls the indoor operative temperature, reaching energy saving potentials of between 7% and 13%. If an operative-temperature-based control is implemented at a position near a low-emissivity surface, energy savings of up to 22% could be achieved. Beneficial contribution is obtained when simulating low-e coating coupled with interior aerogel plaster, where energy savings of 21% and 30% are obtained for 0.5 cm and 1 cm of aerogel plaster, respectively. This thin layer of aerogel plaster demonstrated also to be effective in retrofitting existing walls to reduce the moisture risks. It is worth mentioning that from an architectural point of view, a low- emissivity coating means a metal appearance wall finishing, which needs to be accepted by the occupants.

Influence of EPS, mineral wool and plaster layers on sound and thermal insulation of a wall: a case study

Different envelope solutions are used for the implementation of thermal insulation requirements, assuming that a solution that insures good thermal insulation will automatically insure good sound insulation. The use of External Thermal Insulation Composite System (ETICS) may be one of many solutions. The aim of the experiment was to evaluate how thermal insulation (EPS and mineral wool) and coating (plaster) layers of ETICS influence on sound and thermal insulation of a basic element (wall). The experimental results showed that added thermal insulation (EPS and mineral wool) and coating (plaster) layers of ETICS can influence the sound and thermal insulation of the wall differently. The addition of a thermal insulation layer of ETICS changes sound insulation (increases up to 4 dB) of wall with mineral wool, but in using EPS, has no significant influence. The addition of a coating (plaster) layer over the thermal insulation material layer allows an increase in sound insulation in both cases from 3 dB to 7 dB, but does not change the thermal insulation. The addition of a layer of thermal insulation changes the thermal insulation of basic wall – it increases up to 4.88 m2 K/W with EPS and up to 5.09 m2 K/W with MW, respectively. The influence on sound insulation depends on the type of thermal insulation material used, the presence or absence of a coating (plaster layer) and its thickness, while the influence on thermal insulation does not depend on these factors. It only depends on the presence of the thermal insulation layer.

Influences of Environmental Conditions on the Cracking Tendency of Dry‐Mixed Plastering Mortar

Cracking tendency is one of the important performances of dry‐mixed plastering mortar (DMPM). Environmental condition is a key factor to affect the cracking tendency of DMPM. For the purpose of evaluating the cracking resistance of DMPM and revealing the influence of environmental conditions on the cracking tendency of DMPM, a series of experiments were performed on restriction‐induced cracking behaviors as well as free shrinkage, water loss, and mechanical properties of DMPM. The restricted shrinkage tests were based on ring tests and plate experiments. The results showed that the initial drying age exhibits significant influence on the cracking tendency of DMPM, and there was a stress balance period when the initial drying age was 2 days. But, the phenomena cannot be observed when the initial age was 3 d, 5 d, and 7 d. In order to eliminate the cracking tendency of DMPM, it should avoid water loss from the plaster layer during construction in practical engineering, especially, before initial drying ages.

Thermal Bridge Effect of Aerated Concrete Block Wall in Cold Regions

As a self-insulating building material which can meet the 65 percent energy-efficiency requirements in cold region of China, aerated concrete blocks often go moldy, frost heaving, or cause plaster layer hollowing at thermal bridge parts in the extremely cold regions due to the restrictions of environmental climate and construction technique. L-shaped part and T-shaped part of aerated concrete walls are the most easily influenced parts by thermal bridge effect. In this paper, a field test is performed to investigate the scope of the thermal bridge effect. Moreover, a heat transfer calculation model for L-shaped wall and T-shaped wall is developed. According to the simulation results, the temperature fields of the thermal bridge affected regions are simulated and analyzed. The research outputs can provide theoretical basis for the application of aerated concrete wall in extremely cold regions.