Plaster Layer Research Articles

Causes of cracks in the plaster of unheated stone buildings

Introduction. The objects of the study are unheated stone buildings. Most of them are historical, including cultural heritage sites. The subject of the study is the analysis of the causes of cracks in the inner plaster layer. Damage of the internal plaster coating has a strong influence on the condition of wall paintings and artistic decoration of the exterior walls of preserved historical objects of cultural heritage. There is a lack of systematic studies of the causes of the damage on the walls. The scientific novelty of the work is the development of a finite element model. In this model, a fragment of masonry is considered together with a plaster coating. The practical significance of the study is to establish causal relationships between damage to load-bearing stone walls and internal plaster coatings. The study is aimed at identifying the most significant factors and impacts that influence the appearance of damage in the inner plaster layer of unheated stone buildings and religious buildings.
 
 Materials and methods. A detailed analysis of the stress state of the plaster layer during the course of shrinkage deformations in it was performed. Numerical research methods based on a finite element model of a fragment of masonry with a plaster layer were used.
 
 Results. The paper provides a graph of the dependence of the main tensile stresses on the ratio of the modulus of elasticity of the plaster mortar to the modulus of deformation of the masonry. With an increase in this ratio, the values of the main tensile stresses increase linearly. When they reach a value of 1.0 MPa, they become comparable to the limiting stresses at which a crack is formed. The obtained results are of great practical importance in the development of programs for the inspection, repair and restoration of historical cultural heritage sites.
 
 Conclusions. It is established that the values of the main tensile stresses practically do not depend on the thickness of the plaster layer. Humidity deformations of the plaster layer significantly exceed temperature ones and are the most significant factors for the appearance of cracks on the internal plaster coating of external walls in the absence of force cracks in the walls.

A multi-analytical approach for the characterization of materials, manufacturing process and damage mechanisms of wall paintings in Samye Temple, Tibet

This research focuses on the multi-technique characterization and identification of degradation mechanisms of the wall paintings at the Samye Temple in Tibet, which is considered the first built temple of Tibetan Buddhism with an enormous cultural significance to the region. Wall painting general stratigraphy was thoroughly analyzed by Optical Microscopy (OM), Scanning Electron Microscopy – Energy Dispersive X-Ray Spectroscopy (SEM-EDS) and X-ray Powder Diffraction (XRD). Results reveal a clear sequence, from the interior to the surface, consisting on an adobe wall support, a coarse mud plaster, a fine mud plaster, a white ground layer, a surface paint layer, and a coating layer. The identification of natural and/or synthetic pigments and possible re-painted areas was analyzed by polarized light microscope and SEM-EDS, and subsequently studied using Raman spectroscopy. Results reveal the mineral pigments include red cinnabar (HgS) and red lead (Pb3O4), blue azurite (Cu3(CO3)2(OH)2), green malachite (Cu2CO3(OH)2), yellow orpiment (As2S3), and a gold layer (gold powder). White and black pigments are magnesite (MgCO3) and carbon, respectively. Additionally, the external surface coating varnish found on the top of the paint layer was also analyzed by Transmission Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance mode (FTIR-ATR), Proton Nuclear Magnetic Resonance (H1 NMR), Thermogravimetric analysis (TG), Mass Spectrometry (MS) and SEM-EDX analysis. Results show main components of this coating include acrylates and, possibly, silanes, revealing a recent conservation intervention activity. The hydric expansion/contraction of clay minerals in the adobe support and mud plaster layers and the rigid and impervious acrylate coating layer could have accelerated the deterioration and be the responsible for the development of cracks both at the interface of the different support layer and normal to the wall painting surface, resulting in massive losses. These findings are relevant to better understand the traditional manufacturing process of historic wall paintings in Tibet, which is not fully understood yet, and serve to further conservation activities of this historically rich temple.

Integration of PCM as an external wall layer in reducing excessive heat of building walls

Innovative building approaches, which take advantage of heat energy in buildings, have recently appeared as part of a global effort to save energy. Incorporating phase change material (PCM) into the building envelope helps in reducing energy consumption and regulating energy demand by managing the thermal inertia of designed PCM thermal characteristics. A study was conducted to assess the performance benefits provided by the latent heat of the concrete wall combined with PCM. This study focuses on developing and testing heat barrier performance by incorporating PCM into wall external finishing, i.e. cement plaster and gloss paint. The effect of PCM inclusion in building wall were investigated by experimental work. The results indicate that incorporating PCM into the building wall reduced the surface temperature by up to 9 °C. Furthermore, the application of the PCM in the plaster layer is more reliable in reducing the internal wall surface temperature by a value of 8.1 °C when compared to the PCM in a painted coating. Painted wall panels experienced more significant temperature reduction differences than other wall panels, i.e. 9.2 °C and 9.5 °C, respectively. However, painted wall panels experienced higher internal surface temperatures than external surface temperatures compared to plastered wall panel at night. This could be due to the paint reactions, which are ineffective at releasing internal heat from the building at night. The yearly energy demand is decreased by 64.3% by incorporating PCM to the building wall, with a total annual electricity bill savings of 42.3% (8695.8 kWh yr−1). Therefore, it was concluded that wrapped PCM integrated into plaster layers on external surface building walls could decrease the indoor building temperature and thus contribute to conserving the energy required for an air conditioning system.

Lead and Zinc Pigmented Mural Paint: Discovering Ancient Technologies at Lowry Pueblo Great House in Southwest Colorado

At Lowry Pueblo, small fragments of painted plaster are all that remain of a bold white step pattern mural that once decorated Kivas A and B. We used the following analytical techniques to study these fragments: visual microscopic analysis, portable X-ray fluorescence, scanning electron microscopy with an energy dispersive X-ray spectrometer, powder X-ray diffraction, and radiocarbon dating. We identified zinc oxide and lead sulfate pigment minerals in the glossy white paint, whereas calcium carbonate was identified as the pigment for the matte white paint. Radiocarbon dating of a lead layer places mural production at 1030–1210 cal A.D., consistent with occupation at Lowry Pueblo Great House. Stratigraphic analyses of the painted plaster layers reveals that underlying glossy white paint was applied before the ultimate matte white layer. The change in pigment source and paint recipes demonstrate a design-modifying choice made by the kiva painters.

Common Faults Prevention of Autoclaved Aerated Concrete Block Masonry

Autoclaved aerated concrete block (AACB) is a new kind of green, environmental protection and economical wall material. Its production process can absorb a large amount of industrial waste residue, and the ratio of raw materials can reach more than 70%. However, in the actual construction situation, crack problems such as wall cracking and plaster layer falling off, as well as quality problems such as insufficient strength and easy cracking occur from time to time in the masonry which using AACB. In this paper, the common faults and causes of AACB masonry are summarized and analyzed, moreover, the related prevention and solving measures are put forward for reference in the masonry engineering. This paper can provide reference for the construction specification and quality acceptance of masonry engineering.

A Study of Song Dynasty Polychrome Statue-Making Techniques and Materials in the Sage Mother Hall of the Jinci Temple, Shanxi, China

The polychrome statues of the Sage Mother Hall at the Jinci Temple in Taiyuan city are recognized as one of the three masterpieces of the Jinci Temple. They are also regarded as an outstanding representative of ancient Chinese temple statues. These statues possess great historical, artistic, scientific, cultural and social values, and they are an important physical material for the study of ancient Chinese history, culture, religion, politics and economy, as well as science and technology. The internal structure, plaster layer samples and surface pigments of the polychrome statues of the Sage Mother Hall were analyzed by optical microscope (OM) scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM–EDS), X-ray powder diffraction (XRD), Raman spectroscopy (Raman), X-radiography and other analytical methods in order to gain an understanding of the production process and pigment composition of the polychrome statues of the Sage Mother Hall. According to the findings, the following steps were taken during the production of the polychrome statues that decorate the Sage Mother Hall at Jinci Temple: building a wooden skeleton, fixing the skeleton with rivets or twine, shaping the clay form with coarse clay, shaping the appearance with fine clay, refining the molded appearance, and white substrate layer painting. The majority of the pigments are inorganic mineral pigments: the red pigments include cinnabar and minium; the blue pigments include ultramarine; the green pigments include lavendulan; the yellow pigments include yellow ochre; the black pigments include carbon black; and the white pigments and substrate layers include white lead and lead sulfate. Some of the pigment layers can be seen in multiple layers, which indicates that over the history of the painted statues of the Sage Mother Hall, they have been subject to a series of repainting, with the more recent repainting time perhaps having taken place during the late Qing Dynasty and the following time period.

Materiality of Seclusion: A Decorated Monastic Hermitage in the Dead Sea Escarpment

The monastic practice of Lenten retreats in the desert is attested in ancient Palestine by the early fifth century. However, within the large archaeological corpus of desert monasticism, sites that can be positively identified as Lenten hermitages were previously unattested. The hermitage discovered during the recent survey of the Dead Sea Escarpment is situated in a rock shelter in a narrow natural ledge, part of the high cliff towering the western shore of the Dead Sea. The harsh, arid environment and lack of perennial water sources nearby make the site a suitable abode mainly during the spring season. The walls of the shelter are covered by two layers of plaster bearing the remains of two different decorative programs, adorning the cell with red paintings and repetitive round medallions and blind arcades. Both phases of decoration exhibit initial lining, probably in preparation for relatively long texts. The sophisticated decoration of this isolated hermitage, which was not meant to impress visitors but rather to stimulate spiritual work in solitude far from the distractions of the outside world, provides an exceptional opportunity to discuss the interaction between the landscape, the image, and the written word in the ascetic practices of Palestinian monasticism.

Investigation of convection and radiation heat transfer of paraffinic materials and storage of thermal energy in melting process of PCMs in the cavity with transparent inner walls

Phase change materials have wide applications as thermal energy storage systems. Due to the low thermal conductivity of these materials, lots of efforts have been made to increase the thermal conductivity and efficiency of thermal energy storage systems. In this numerical study, convective and radiation heat transfer on a cavity with transparent inner walls have been investigated considering the effects of buoyancy force and viscosity of phase change materials. For this purpose, computational fluid dynamics that have high accuracy in calculations have been used. The considered wall is made of brick, in which the cavity containing phase change materials is included and layers of cement and plaster are placed on the wall. The results indicate that increasing the heat flux increases the effects of convective heat transfer. In addition, by applying radiation effects, the melting process of paraffin materials increases by 31%. Due to the transparency of the inner walls of the cavity, the radiation process occurred surface to surface. Therefore, with increasing amount of molten material, the radiation effects increase, the reason for this is that RT24 material is more transparent in liquid form than solid material. Also, increasing the heat flux from 50 to 100 and 300 (w/m2) increases the speed of the melting process by 19.3% and 27.2%, respectively.

Assessment of cleaning techniques and its effectiveness for controlling biodeterioration fungi on wall paintings of Maijishan Grottoes

Biodeterioration is one of the main challenges in conservation of cultural heritage. This study tested and evaluated non-destructive methods to clean and control the microbial mycelia grown on the surface of wall paintings at the World Cultural Heritage Site of Maijishan Grottoes in China. Culture-dependent methods were used for isolation of fungi prior to identification by ITS rRNA gene sequences. The mycelia grown on the surface of wall paintings were removed with soft brushes under a negative pressure provided by a modified vacuum pump, and the pre-screened biocides were then selected and applied. Using a portable microscope, a microbial ATP bioluminescence detector, and a colorimeter, the effectiveness of cleaning and controlling against fungal mycelia on the wall paintings was evaluated. The results showed that the fungal isolates were dominated by Arachnomyces spp. with 92.28% sequence identity. Other major culturable fungal isolates were Parengyodontium album, Beauveria bassiana, and Scopulariopsis brumptii. The microscopic examination indicated the surface of the wall paintings was nearly free of visible fungal mycelia after the manual removal. There was a significant reduction of ATP bioluminescence before (43,303 ± 10, 280 RLU/cm2) and after (2,833 ± 388, RLU/cm2) the mechanical removal. The color difference (ΔE∗ab value) were less than 2.0 before and after biocide treatment, such difference could almost be ignored. Additionally, octylisothiazolinone was found to be the most efficient biocide for controlling fungal growth and could be an emergency protection measure. Furthermore, the key environmental factors that triggered periodic breakouts of the microorganisms on wall paintings were long-term higher relative humidity at the interface of earthen plaster layer and supporting sandstone during raining seasons and poor ventilation of the cave. This study provides a reference for the scientific conservation of biodeteriorated ancient wall paintings.

THE IMPACT OF PLASTERING ON THE HYGROTHERMAL BEHAVIOUR OF HISTORICAL SANDSTONE LOCATED IN THE COASTAL REGION OF LEBANON

In an unusual trend in the conservation practice of built heritage in Lebanon, the external plaster layer, which protects the sandstone from weathering factors, is being removed for aesthetic reasons. These buildings are in a coastal region, hot humid climate in the summer and moderate cold weather in the winter. This paper discusses the importance of external and internal plastering of the historical sandstone bearing wall, by the mean of a computational tool that underlines the role of the plastering in the hygrothermal behaviour of the historical stone, in the aim to validate the practice of the ancestors in covering the envelope of their buildings to avoid the degradation of these natural stones. The methodology adopted in this paper is a comparative quantitative study, using a hygrothermal simulation modelling tool, named Wufi Pro, which is a standard program for evaluating moisture conditions in building envelopes developed by the Fraunhofer Institute for Building Physics (IBP) Stuttgart, Germany. The results are in the form of values for the heat and moisture fluxes through the high porosity sandstone assembly that composes the building envelope. These values represent the hygrothermal behaviour of the stone, and they are compared between two cases, one without plastering while the second has the inner and outer layers of traditional plaster. The analysis of the results is guiding to a conclusion that favours one of the two cases, taking into consideration the interstitial condensation threat avoided by the means of plastering.

Characterization of Wall Paintings of the Harem Court in the Alhambra Monumental Ensemble: Advantages and Limitations of In Situ Analysis.

Non-invasive techniques (X-ray fluorescence, XRF, and Raman spectroscopy) were used for the study of the Hispano Muslim wall paintings. Principal component analysis (PCA) was performed on the semi-quantitative XRF results directly provided by the in-built factory calibrations with minimum user manipulation. The results obtained were satisfactory and highlighted differences and similarities among the measurement points. In this way, it was possible to differentiate the decorations carried out on gypsum plasterwork and the wall paintings over lime plaster. The color palette, revealed by combining the results from XRF and Raman spectroscopies, comprised the pigments hematite, lapis lazuli, cinnabar (in poor conservation state), and possibly, carbon. Evidence of past interventions was also provided by PCA on XRF data, which detected the presence of Pb, Ba, and Zn in some areas. Furthermore, the preparation layers have been studied in detail on cross-sections of two microsamples. Several layers of lime plaster with a compact microstructure have been observed. The characteristic of the pictorial layer and the identification of calcium oxalate point to the use of a secco-technique. The main alteration identified was a gypsum surface layer covering the painting and signs of plaster deterioration due to gypsum migration to more internal areas. Finally, the comparison with the observations made by restorers in previous interventions on these paintings revealed the importance of the representativeness gained with the in situ study, which enabled the analysis of a high number of areas.

Lime and Cement Plasters from 20th Century Buildings: Raw Materials and Relations between Mineralogical–Petrographic Characteristics and Chemical–Physical Compatibility with the Limestone Substrate

This paper deals with the “modern” plaster mortars based on air lime, hydraulic lime, and cement used between the 1950s and 1990s of the last century, taking, as a case study, a historical building of the Cagliari city whose foundations and ground floor are cut into in-situ limestone. Different plaster layers (i.e., arriccio and intonachino, paint), applied on the excavated limestone walls, were collected from cave-room. All samples were analysed by optical and electron (SEM-EDS) microscopy and X-ray diffractometry (XRD) in order to define their microstructures, textures and compositional features. In addition, real and bulk density, water and helium open porosity, water absorption kinetic, and saturation index were measured. By microscopic imaging analyses, the binder/aggregate ratio as vol.% was determined. Results revealed that cement mortars, composed mainly of C-S-H, C-A-H, and C-F-H phases, given their high hydraulicity, low open porosity, and a rigid behaviour, showed a good chemical but not physical–mechanical adherence, as they were often found detached from the substrate and frequently loaded with salt efflorescence. On the contrary, the hydraulic lime-based mortars, characterised by a binder composed of C-S-H and C-A-H phases and calcite derived from the portlandite carbonation, showed a greater affinity with limestone substrate and other plasters. Thus, they are more suitable to be used as a repair mortar, showing a long durability on the time. The thin air lime-based plasters (intonachino) showed a good adhesion to the substrate, exerting their coating function better than the harder, cement-based mortars. Lime-based wall paints have a good chemical adhesion and adaptability to the irregular surface of the substrate, due to low thickness of lime paint layers (<1 mm) that confers an elastic physical behaviour.

New Form, New Material and Color Scheme, the Exposed Concrete Phenomenon—The Centennial Hall in Wrocław

The aim of the article is to present the remarkable changes in architecture that took place in the 20th century. They can easily be called a revolution regarding the architectural form and the color scheme. Progress was being made through the development of reinforced concrete production methods. In the German Empire (Deutsches Kaiserreich), this material quickly found applications in more and more interesting solutions in architectural structures. In Wrocław (formerly Breslau), then located in the eastern German Empire, exceptional architectural works were realized before and after the First World War using new technology. In 1913, an unusual building was erected—the Centennial Hall, designed by Max Berg (inscribed on the UNESCO World Heritage List in 2006). Berg’s work was inspired by the works of both Hans Poelzig and Bruno Taut. On the one hand, it was a delight with the new material (the Upper Silesian Tower at the exhibition in Poznań, designed by H. Poelzig) and, on the other hand, with the colorful architecture of light and glass by B. Taut (a glass pavilion at the Werkbund exhibition in Cologne). Max Berg left the concrete in an almost “pure” form, not hiding the texture of the formwork under the plaster layer. However, stratigraphic studies of paint coatings and archival inquiries reveal a new face of this building. The research was carried out as part of the CMP (Conservation Management Plan—prepared by the authors of the article, among others) grant from The Getty Foundation Keeping It Modern program. According to the source materials, the architect intended to leave the exposed concrete outside of the building, while the interior was to be decorated with painting, stained glass, and sculpture. The stratigraphic tests showed that the external walls were covered with a translucent yellowish color coating. Thus, the Centennial Hall shows a different face of reinforced concrete architecture.

THE MEMBRANE DISTILLATION ABILITY TO REMOVE CALCIUM ION FROM DAIRY WASTEWATER

In this research the membranes distillation was used to remove calcium ions from heavy sewers at dairy plants in Iraq. This method is easy to operate, easy to manage and has many economic benefits. A chemical treatment was carried out on it using alum as a coagulant, different tests achieved samples before and after passing MD, according to APHA, AWWA, WEF. The results showed that obtained in water treatment trust that has been manufactured and edited according to the characteristics of the water waste the interests of the dairy capacity of this method to remove the calcium ion to a certain extent it is when the concentration reaches the inside of this ion to 1428.57 mg per liter, where to start the composition of hydroxides of calcium responsible for pain. The optimal working temperature ranges from 20-22 ° C and the flow is around 0.66 kg.m-2.h-1, here was the result of a layer of plaster that led to clogged membrane and folding and was stopped for washing and cleaning.

The effect of temperature, humidity and mechanical properties on crack formation on external thin plasters of ETICS

External Thermal Insulation Composite Systems (ETICS) are widely used in the northern hemisphere in retrofitted and new external walls. The outer layer of ETICS is usually a thin layer of plaster. The effects of temperature and humidity on the hygrothermal behaviour and mechanical properties of thin plasters have been quantified by conducting several experiments to determine the possibility of crack formation. Combinations of plasters using four types of binders are tested: mineral, polymer, silicate and silicone. Plasters are tested as four systems consisting of a base coat, a glass-fibre reinforcement mesh and a finishing coat. Sorption curves of the plaster systems are determined to gather data for numerical simulations. The coefficients of thermal and hygroscopic expansion are determined. The modulus of elasticity and tensile strength of four different plasters are measured to allow the calculation of crack formation in ETICS and suggest the distances between the deformation joints. The method demonstrated in this paper makes it possible to calculate the crack formation caused by the temperature and moisture shrinkage in the thin exterior plaster of ETICS.

АНАЛИЗ ВЛИЯНИЯ МЕТОДОВ ВВЕДЕНИЯ ОРГАНОМИНЕРАЛЬНОЙ ДОБАВКИ В СТРОИТЕЛЬНЫЕ РАСТВОРЫ НА МЕЛКИХ ПЕСКАХ

the use of technogenic raw materials in the production of building composites is an urgent direction in the technology of production of building materials in view of its economic efficiency, environmental effect and wide possibilities of their application. Recently, the issues of environmental safety in the production of building materials, the possibility of their processing and disposal have come to the fore. All this is dictated by the need for energy and resource conservation, the massive depletion of natural reserves and the progres-sive pollution of the environment due to anthropogenic activities. Construction composites provide ample opportunities for recycling of secondary raw materials, as their structure allows them to be used not only as a filler, but also in some cases as additives for regulating certain properties. More studied and widely used are ash and slag mixtures on the basis of which various organomineral additives are developed. So, on the territory of the Chechen Republic there are dumps of ash and slag mixtures, which, according to their chem-ical and mineralogical composition, are suitable for the design of organomineral additives and fillers in con-struction concretes and solutions. Building solutions are widely used for interior and exterior finishing works during the construction of construction projects in the Chechen Republic, which is characterized by high humidity in the winter, which provokes deformations of the plaster layer on facades. In this article, the de-velopment of an organomineral additive based on an ash-slag mixture is considered to improve the quality of mortar mixtures resistant to such conditions.

Robotic Plaster Spraying: Crafting Surfaces with Adaptive Thin-Layer Printing.

Embedded in a long tradition of craftsmanship, inside or outside building surfaces, is often treated with plaster, which plays both functional and ornamental roles. Today, plasterwork is predominantly produced through rationalized, time-, and cost-efficient processes, used for standardized building elements. These processes have also gained interest in the construction robotics field, and while such approaches target the direct automation of standardized plasterwork, they estrange themselves from the inherent qualities of this malleable material that are well known from the past. This research investigates the design potentials of robotic plaster spraying, proposing an adaptive, thin-layer vertical printing method for plasterwork that aims to introduce a digital craft through additive manufacturing. The presented work is an explorative study of a digitally controlled process that can be applied to broaden the design possibilities for the surfaces of building structures. It involves the spraying of multiple thin layers of plaster onto a vertical surface to create volumetric formations or patterns, without the use of any formwork or support structures. This article describes the experimental setup and the initial results of the data collection method involving systematic studies with physical testing, allowing to develop means to predict and visualize the complex-to-simulate material behavior, which might eventually enable to design with the plasticity of this material in a digital design tool.

Evaluating the Impact of Indoor Insulation on Historic Buildings: A Multilevel Approach Involving Heat and Moisture Simulations

The energy refurbishment of historic buildings is a complex task for building envelope designers who need to carefully consider building conservation guidelines and principles. In most cases, external wall insulation techniques can determine an unacceptable alteration of the historical value of a building. For this reason, internal wall insulation techniques have been used widely in the last few decades. Nevertheless, dealing with internal wall insulation requires a complex design to avoid the risk of condensation and moisture-related pathologies. Moreover, an internal wall insulation may have a relevant impact on indoor comfort conditions. In this paper, the Monastery of Santa Maria de Monfero in Galicia (Spain) has been adopted as a building case study to compare different technological solutions based on: (i) an insulating plaster layer, (ii) dry counter wall systems. In the first step, heat and moisture transfer simulations of the wall components were performed to analyze the hygrothermal behavior of the different alternatives considering two different climate conditions. In a second step, a simulation of the whole building was performed to analyze the impact of the retrofitting strategies on the indoor climate and on the building heating and cooling demand. The obtained results show that the counter wall solution leads to higher energy savings during the heating season in the colder winter climate. However, the use of insulating thermal plaster could also be a viable solution since they lead to several advantages in summer because of their higher thermal inertia. Therefore, the selection of the most appropriate insulation technique has to be evaluated carefully considering the outdoor/indoor climate and using a case-by-case approach.

Hydraulicity of lime plasters from Teotihuacan, Mexico: a microchemical and microphysical approach

Hydraulicity is a well-known characteristic of mortars and plasters from the Roman, Late Roman, and Medieval periods, while the use of hydraulic mortars in pre-Columbian Mesoamerica and Central Mexico in particular, has not received equal attention. To address this issue, in this paper, we discuss the problem of hydraulicity and suggest a method to study it in Mesoamerican plasters. To prove the effectiveness of this method, we selected plaster samples from the archaeological site of Teotihuacan (Mexico), the main city of Central Mexico during the Classic period. The characterisation of plaster samples confirmed that, similar to other Teotihuacan plasters, they are made of two layers: the outermost layer (enlucido), composed of a mixture of lime and volcanic glass shards, and the underlying layer locally called firme, consisting of crushed volcanic scoria (tezontle) mixed with a mud-based binder. The compositional characterisation of the plasters confirmed their hydraulicity and the combination of microchemical (energy dispersive spectrometer (EDS) microchemical analysis), microphysical (Vickers microhardness), and petrographic (optical microscopy) measurements demonstrated that it was not the presence of glass shards in the external plaster layer which produced hydraulicity, as we originally thought. Instead, this was due to the reactivity of the tezontle, present in the lower layer.This suggests that the small thickness of the enlucido layer, in addition to save the amount of lime used, increased its performance, promoting chemical reactions with the tezontle in the contact layer and that the glass shards played another role in the mixture, rather than producing hydraulicity.

Life cycle assessment of interior partition walls: Comparison between functionality requirements and best environmental performance

This research analyses 44 interior partition walls (IPW) in the context of Spanish residential sector and establish the systems’ environmental profile through the application of the life cycle assessment technique. The analysis is performed within the stages of production to construction (“from cradle to handover” approach), using Ecoinvent as background database and ReCiPe as the impact assessment methodology. The analysis combines the technical requirements with the environmental data to establish the profile of the different multi-layer construction systems, with the objective of supporting the selection of the optimal elements from the design phase and promoting the development of regulations to include considerations of the embodied environmental impact in the constructive systems. The results show that the product stage has the greatest contribution to the environmental impact (78% average), followed by transport (21% average) and construction with <1% average. A layer contribution analysis shows that the contribution of greater representativity can vary according to the nature of the materials used and that the base layer is the element with greater generation of emissions in most of the IPW (48% average), followed by the exterior layer (30% average) and the insulation and plaster layers with 12% and 11% respectively. The results emphasize the importance of including the technical requirements and evaluating the multi-layer components as an entire element, rather than evaluating single products, in order to obtain more representative and trustworthy results for real practice application.