Lime Plaster Research Articles

The impact of renovation plasters on desalting and drying of damp walls

Renovation plasters have been used in the construction industry since the early 1970s. Although the benefits they offer are obvious, there were also critical opinions about the adverse effect of the plasters on the durability of the walls. The complaints mainly concerned the tendency of renovation plasters to accumulate water in the wall, which in the winter time resulted in peeling of the plasters. As a result, more and more often conservators began to refrain from applying renovation plasters in historic buildings in favour of lime plasters without the porosity-increasing additions. The article presents an analysis of the walls which can be encountered in the renovation practice. For selected buildings undergoing renovation, the moisture content of walls, their strength, microstructure and water sorption were determined. Renovation plasters, whose microstructure and properties matched the properties of the walls, were used for their renovation. Plasters with optimal microstructure enabled salt accumulation, crystallized salts did not lower their durability and did not lead to cracking or peeling.

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.

A Painted Viking-Age Sculpture from York

This paper records and discusses a recent discovery of a Viking-age stone carving from York, the subsequent cleaning and conservation of which has revealed large areas of original lime plaster priming layer and pigment coating, including the first recorded use in Northumbrian sculpture of lead white.

Determination of Thermal Conductivity of Silicate Matrix for Applications in Effective Media Theory

Silicate materials have an irreplaceable role in the construction industry. They are mainly represented by cement-based- or lime-based materials, such as concrete, cement mortar, or lime plaster, and consist of three phases: the solid matrix and air and water present in the pores. Therefore, their effective thermal conductivity depends on thermal conductivities of the involved phases. Due to the time-consuming experimental determination of the effective thermal conductivity, its calculation by means of homogenization techniques presents a reasonable alternative. In the homogenization theory, both volumetric content and particular property of each phase need to be identified. For porous materials the most problematic part is to accurately identify thermal conductivity of the solid matrix. Due to the complex composition of silicate materials, the thermal conductivity of the matrix can be determined only approximately, based on the knowledge of thermal conductivities of its major compounds. In this paper, the thermal conductivity of silicate matrix is determined using the measurement of a sufficiently large set of experimental data. Cement pastes with different open porosities are prepared, dried, and their effective thermal conductivity is determined using a transient heat-pulse method. The thermal conductivity of the matrix is calculated by means of extrapolation of the effective thermal conductivity versus porosity functions to zero porosity. Its practical applicability is demonstrated by calculating the effective thermal conductivity of a three-phase silicate material and comparing it with experimental data.

Impact of fiber treatment on the fire reaction and thermal degradation of building insulation straw composite

In this paper, both treated and untreated straw fibers are used to manufacture the light-weight composite for building insulation. The main objective of this work is to investigate the effect of the treatment on the thermal degradation and flammability of the material in order to examine his fire behavior. The selected wheat and barley straws are mixed with lime or gypsum plaster in this experimental investigation. In order to improve the mechanical properties of the composite, the straw fibers are treated with linseed oil and boiled water for decreasing their water absorption and increasing their compatibility and adhesion with the binder respectively. The treatment is carried out by total impregnation in the boiled water and linseed oil. The different composites are manufactured using mixture procedure optimized in previous works of the authors. Then the treated and untreated composite specimens are analyzed and compared through TG-DSC analysis to study their combustion process at microscopic level, and flammability test to study their fire reaction at macroscopic level. The properties of composites based on the fibers treated with linseed oil vary significantly.

Properties of Modified Lime-Based Plasters for Renewal of Historical Buildings Exposed to Accelerated Carbonation Test

This paper deals with determination of basic physical, mechanical, thermal and water transport properties of lime–based plasters whose composition was modified by the addition of diatomaceous earth. To eliminate possible deterioration of original lime plaster by natural weathering, the hydrophobic admixtures on the stearate and oleate basis were added into the plaster mixtures and boiled linseed oil as a painting was applied. All studied material parameters were tested after 28 days of wet curing and after exposition to accelerated carbonation. The results of examined properties of developed plasters gave promising outcomes for the use of hydrophobised materials in renewal of historical buildings. Based on the obtained data, plaster made of lime hydrate, diatomite, and combination of water repellent agents can be recommended for renovation purposes.

Crystallization and Colloidal Stabilization of Ca(OH)2 in the Presence of Nopal Juice (Opuntia ficus indica): Implications in Architectural Heritage Conservation

Hydrated lime (Ca(OH)2) is a vernacular art and building material produced following slaking of CaO in water. If excess water is used, a slurry, called lime putty, forms, which has been the preferred craftsman selection for formulating lime mortars since Roman times. A variety of natural additives were traditionally added to the lime putty to improve its quality. The mucilaginous juice extracted from nopal cladodes has been and still is used as additive incorporated in the slaking water for formulation of lime mortars and plasters, both in ancient Mesoamerica and in the USA Southwest. Little is known on the ultimate effects of this additive on the crystallization and microstructure of hydrated lime. Here, we show that significant changes in habit and size of portlandite crystals occur following slaking in the presence of nopal juice as well as compositionally similar citrus pectin. Both additives contain polysaccharides made up of galacturonic acid and neutral sugar residues. The carboxyl (and hydroxyl) functional groups present in these residues and in their alkaline degradation byproducts, which are deprotonated at the high pH (12.4) produced during lime slaking, strongly interact with newly formed Ca(OH)2 crystals acting in two ways: (a) as nucleation inhibitors, promoting the formation of nanosized crystals, and (b) as habit modifiers, favoring the development of planar habit following their adsorption onto positively charged (0001)Ca(OH)2 faces. Adsorption of polysaccharides on Ca(OH)2 crystals prevents the development of large particles, resulting in a very reactive, nanosized portlandite slurry. It also promotes steric stabilization, which limits aggregation, thus enhancing the colloidal nature of the lime putty. Overall, these effects are very favorable for the preparation of highly plastic lime mortars with enhanced properties.

A 10,400-year-old sunken lime kiln from the Early Pre-Pottery Neolithic B at the Nesher-Ramla quarry (el-Khirbe), Israel

The Pre-Pottery Neolithic B (PPNB) is the first period in human cultural evolution that is characterized by the extensive production of lime plaster for architectural, decorative and ritual purposes. The production of large quantities of lime plaster requires the operation of a lime kiln, a structure where limestone cobbles are heated to high temperatures (>600°C) to obtain quicklime, which is then mixed with water to form a moldable lime putty. However, little is known about lime kilns and plaster production processes during the PPNB. This may be because the technology used at that time was simple and left few traces that are unique to lime plaster production. These include combustion features rich in lime plaster and heat-altered sediments, which are difficult to identify through only a visual inspection of the archaeological context. Here we report the study of a small sinkhole at the Nesher-Ramla quarry in Israel, which yielded Early PPNB artifacts. Using infrared spectrometry and micromorphology of sediments, we identified in-situ deposits of heat-altered sediments rich in fragments of burnt limestone, lime plaster, and wood ash in the form of charcoal, phytoliths and siliceous aggregates, which are features consistent with the operation of a lime kiln. Charred botanical remains were characterized and used for radiocarbon dating, which determined the age of the site at 10,400cal BP. We therefore conclude, based on the examination of the microscopic archaeological record, that this sinkhole was used as a lime kiln during the Early PPNB.

The influence of the pore structure on the moisture transport in lime plaster-brick systems as studied by NMR

This paper presents an experimental analysis of the porous structure and drying kinetics of lime-based plasters and plaster-brick systems using different methods. The effect of adding a water-repellent admixture (linseed oil) to the plasters was also evaluated. Nuclear Magnetic Resonance (NMR) was used to measure moisture profiles during drying of mono-material plaster specimens and of specimens constituted by the same plasters applied on fired-clay brick. NMR transverse relaxation time was used to examine the pore water distribution. The NMR moisture profiles showed that the drying behaviour of the water-repellent mono-plasters differs slightly from the reference, but when applied on brick, it significantly hinders the drying of the substrate. The results indicated that the addition of linseed oil to the lime plaster has negatively influenced the bonding process and created an hydraulic resistivity for the moisture to flow from the brick to the plaster during drying. This phenomena was mainly atributed to three factors: i) hydrophobization of part of the mortar pores; ii) the development of air bubbles related to entrained air during the mixing process; and iii) the mismatch between the physical-chemical properties of both systems, namely the different pore network and surface energy, which seems to affect the interpenetration of both porous layers.

Palatial architecture under the microscope: Production, maintenance, and spatiotemporal changes gleaned from plastered surfaces at a Canaanite palace complex, Tel Kabri, Israel

Modern archaeology in the Near East has paid little attention to construction materials and techniques of monumental architecture within the forming cities of the Bronze Age. We present here a study of plastered surfaces in a Middle Bronze Age palace located at Tel Kabri, a Canaanite polity in the southern Levant that was connected to the Aegean world. Recent excavations uncovered many plastered surfaces within the palace and several satellite monumental structures. In order to identify the types of plaster used in construction and maintenance of the site, as well as understand spatiotemporal patterns associated with the use of plaster, we systematically sampled plaster floors and possible wall/ceiling plaster in more than ten room contexts within five monumental structures. Fourier Transform Infrared (FTIR) spectroscopy and polarized light microscopy (micromorphology) were used in tandem, demonstrating that two types of plasters exist at the site – geogenic, prepared from crushed/pulverized chalk and pressed into flat surfaces, and pyrogenic lime plaster. Lime plaster appears to have been prepared using the cold manufacture technique, i.e., from aged lime putty, and was often applied as coats, indicating maintenance. A most surprising observation is the identification of lime plaster tempered by chaff. To our knowledge, such a technology has not been identified previously and is not reported ethnographically or historically. Spatial patterns reveal that lime plaster was applied in contexts of high distinction (e.g., ceremonial, ritual) while geogenic plaster underlined contexts of more domestic nature (e.g., residential, storage). Temporal changes in plaster technology have not been identified throughout the life span of the palace. The rather limited use of lime plaster may be related to craft specialization and/or environmental impact. Future research should focus on systematic studies in other monumental structures in order to allow understanding of technology transfer and interconnectedness in the ancient Near East.

Castle of Kirkuk قلعة کرکوک

Castle of Kirkuk قلعة کرکوک

PCM-enhanced Lime Plasters for Vernacular and Contemporary Architecture

Phase Change Materials (PCMs) have the ability to absorb and release thermal energy, in the form of latent heat, during the melting or solidifying processes respectively. Thus, they may be used as additives in the production of thermally efficient composite building materials, such as plasters. This paper focuses on the design and production of PCM-enhanced lime plasters with significantly low thermal conductivity and increased specific heat capacity. The aforementioned plasters are appropriate for application in southern European climatic conditions. Due to their compatibility with traditional substrate materials, they may also be used for the renovation and retrofitting of existing structures.

The ancient pozzolanic mortars and concretes of Heliocaminus baths in Hadrian’s Villa (Tivoli, Italy)

The aim of this work is the physical and mineralogical-petrographic characterization of the mortars from the Baths with Heliocaminus, a special and unique architectural building in the complex of the Hadrian’s Villa in Tivoli. Thirty samples were investigated for composition and physical properties (density, porosity, water absorption, mechanical strength, particle size distribution of aggregate, etc.), representative of eight mortar groups: cubilia bedding mortar, brick bedding mortars, floor-coating and wall-coating bedding mortars, floor (rudus) and wall conglomerates (trullisatio), vault concretes, and lime plasters (arriccio). Physical parameters, together with the microscopic analysis and binder/aggregate ratio determined in three ways using image analysis (on thin sections and on specimens) and weight-data from dissolution of binder, have shown an interesting relationship between the physical-compositional characteristics and the function of mortars within the structure of the Heliocaminus baths. To identify the minerals and the reactant phases between binder and aggregate, as well as the hydraulic degree, selected samples were analyzed with x-ray powder diffraction, thermogravimetry, and differential scanning calorimetry techniques. The obtained results provide a close relation between pozzolanic characteristics and physical-mechanical properties of the mortars (i.e., punching strength index).

Application of Ceramic Powder as Supplementary Cementitious Material in Lime Plasters

In this paper, the properties of plasters based on lime – brick powder binder of varying composition (ceramics content from 0 to 80 %) are studied. The plasters are prepared with a constant water amount. The pore size distribution is thus influenced in a positive way; the total porosity increases with the ceramics content but the volume of capillary pores is reduced. It results in lower water vapor diffusion resistance factor while the apparent moisture diffusivity coefficient increases just moderately. The influence of ceramic on strength of plasters is not found very important. The thermal conductivity of plasters containing ceramics is lower than those with the pure lime what is again in agreement with the pore size distribution. It can be concluded that fine brick powder can be used as pozzolanic admixture in lime based plasters with a positive influence on its functional parameters.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7433

Identifying a technological style in the making of lime plasters at Teopancazco (Teotihuacan, México)

The aim of this article is to focus on the technology of archeological plasters at Teotihuacan (Central Mexico), from the Classic Period (200–650 A.D.), focusing in the study of Teopancazco, a neighborhood center in the city. Petrographic and chemical analyses by OM, SEM-EDS, and LA-ICP-MS were conducted to characterize samples from different constructive phases and sectors of the neighborhood center, to determine the provenance of the raw materials employed in the manufacturing (e.g., volcanic glass shards) and to assess whether a shift occurred in the manufacturing of plasters and in the procurement strategies of raw materials during the different phases. The results of the analyses show that almost no changes occurred in the making of the plaster during more than four centuries and allow us to consider the presence of a technological style in their manufacture, which is characterized by the making of plaster by mixing lime with volcanic glass shards, which in the case of Teopancazco were derived from the Altotonga (Veracruz) magmatic system. The data at our disposal suggest that this style was developed in Teopancazco and later introduced throughout the city of Teotihuacan in the Early Xolalpan phase (A.D. 350), although we still do not know whether the provenance of the raw materials is the same. The wide distribution of this technological tradition could be due to the technological properties of the materials and/or the influence of the intermediate elite who ruled over Teopancazco. The paper confirms that the study of material culture and technology sheds light on broader cultural aspects of ancient societies.

Valuation Supports Green University: Case Action at Mediterranea Campus in Reggio Calabria

Civil society, economies, governments are asking to Universities to find a solution for Global Warming problems. Since they are mainly due to human settlement and continuous development and construction, research strategy has singled out Architecture Passivation or Building Greening as a first solution; thereby establishing as its main goal the start-up of real world prototype works, experimental chantiers or building sites, as well as their implementations and monitoring. Geomatic Valuation University Laboratory (GeVaUL) is carrying out a direct experience in real-world implementation of sustainability, designing a strategy for the Mediterranea University campus greening and “passivation” (= energy efficiency). It is done through careful climatic calculation of academic building thermal behavior, and the consequent economic and physical cost-effectiveness valuation of interventions for passivation, i.e. for radical enhancement of energy efficiency. Knowledge of cost-effectiveness valuation has been applied to architectures i.e. buildings or facilities of University Campus in Reggio Calabria. GeVaUL designed greening and building insulation obtained by using ecological cork and bio-ecological lime plaster with impressive well-being regulatory power. Technical Bodies of Central State (Ministry of Industry) and Regional Governments found this approach innovative and appropriate. They are investing in passivation of some University buildings using bio-ecological cork and natural lime plaster, and providing investment capital. Furthermore real world bio - ecological sustainable retrofitting sites have been set up for selected University buildings. Evidence gained thanks to the above experimentation has been applied to simulate passivation of the entire Latin Quarter area (surrounding the University), producing relevant impact with potential influence on local and regional economy.

THE CONSERVATION OF AN EGYPTIAN POLYCHROME WOOD COFFIN FROM LATE PERIOD

This paper describes the treatment and conservation of the polychrome wooden coffin for theunknown mummy of the late period that was in Saqqara stepped pyramids` stores. It sufferedfrom aspects of damage represented in damaging into large fragments, infecting by microorganism,accumulation of dusts and cracks that are varied in shapes and sizes in thedifferent layers of painting. The components of the polychrome wooden coffin were studiedthrough investigation and using various analysis methods such as X-Ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR), light Optical microscope (LOM) and Scanningelectron microscopy with energy-dispersive analysis of elements (SEM-EDX). The resultsindicated that the type of the coffin wood is Cypress (Cupressussempervirens), and there arefive types of fungi that had been grown on it. They are Aspergillusniger, Aspergilusflavus,Alternaria alternate, Emericella nidulans and Penicillium steckii. The ground layers consistedof two layers; coarse layer (clay plaster) and finer coat (lime plaster).The black, pink, andyellow pigments consisted of Pyrolusite, Hematite mixed with Gypsum and Goethiteconsecutively. The medium color was animal glue. Therefore, the current study includedmaking conservation and maintenance of the coffin, mechanical and chemical cleaning,fixation of the paint layer flakes, facing (surface protection), sterilization, reinforcement...etc.

Fiber-Reinforced Polymer Nets for Strengthening Lava Stone Masonries in Historical Buildings

The strengthening of masonries is a crucial step in building restoration works because of its relevance, mostly with regard to the improvement of building seismic behavior. Current building technologies are based on the use of steel nets which are incorporated into cement plasters. The use of steel has a number of contraindications that can be solved by using composite materials such as glass fiber nets, which have high mechanical characteristics and lightness, elasticity, corrosion resistance, and compatibility with lime plaster. Building interventions, that take into account the application of glass fiber nets, are very sustainable from several points of view, e.g., material production, in situ works, economic cost and durability. In Italy, several experiments have been carried out in situ with the aim of testing the mechanical characteristics of masonries which have been treated with fiber-reinforced polymer (FRP) nets. This paper deals with a series of in situ tests carried out during the restoration works of an important historical building located in Catania (Sicily, Italy). The results achieved are largely positive.

Materiality, regimes of value, and the politics of craft production, exchange, and consumption: A case of lime plaster at Teotihuacan, Mexico

Political economy has provided a broad framework for the study of power relations in early complex societies, but its top-down approaches have limitations for understanding the simultaneous formation of unequal and equal social relations. Through the conception of power as heterogeneous, contradictory, and multidimensional, this study addresses how inequality and equality are constituted through production, exchange, and consumption of material objects. Recent material culture studies grounded in practice theories highlight material objects as both medium and consequence of social practice and negotiation. Such a conception of material culture leads us to explore consumption as a key theoretical and methodological concept to understand the relationship between material culture patterns and social reproduction and transformation. This study explores how consumer demand is created by examining the process of the creation and transformation of the regimes of value, which allows to address the entanglement of material properties, multiple agencies, and the acts of production, exchange, and consumption. A case study from Teotihuacan documents archaeological evidence of changing distribution, direct evidence of production, and material characterization of lime plaster and demonstrates how changing social relations were embodied by production, exchange, and consumption of lime plaster.

Aragonite–vaterite–calcite: Polymorphs of CaCO3 in 7th century CE lime plasters of Alampur group of temples, India

This paper study the occurrence of aragonite–vaterite–calcite: Polymorphs of CaCO3 in the ancient lime plaster works of south India’s Alampur group of temples that was under submerged condition due to past construction of Srisailam hydroelectric dam on Tungabhadra river just nearby the temples. For the proper examination of the Alampur plaster, we used analytical methods such as onsite observation, petrological thin section, XRF, XRD, FTIR, SEM – EDX and Raman Spectroscopy. The presence of polymorphs of CaCO3 was confirmed through XRD, FTIR, SEM – EDX and Raman Spectra of the plaster. The occurrence of CaCO3 polymorphs may be due to the action of invertebrates on initial submergence, self healing of the lime due to wet and dry cycle in the presence of Mg that promoted the formation of polymorphs. Microscopic mineralogical analysis showed mixing of sub-angular to sub-rounded, medium to low maturity sand and coarse silt character aggregates of silica rich lithology. The identification of phthalocyanine blue dye in the plaster by Raman spectroscopy may be part of present day rituals. This work is a holistic approach to find out the composition of ancient lime towards protecting the sand stone masonry of the temple by applying compatible lime plasters to arrest the deterioration.