Lime Plaster Research Articles

Traditional Building Knowledge in Indian Lime and Earthen Plasters

India's traditional building systems and knowledge involving natural materials provide fine examples of low-carbon, place-adaptive architectural solutions as well as embodying simplicity and holistic sustainability. They utilize locally available materials prepared and applied so as to build structures and dwellings that are resilient to climate conditions and able to provide comfort and livability. Culturally, this knowledge is transferred orally from generation to generation and continuously recreated. Unfortunately these knowledge systems and practices have become endangered owing to a rupture in their continuity for reasons such as a preference for and incentivization of easier conventional solutions like cement and steel. With a focus on natural plasters used traditionally, this paper highlights some of these diverse plasters along with their natural additives.

Application of deep learning algorithms for identifying deterioration in the ushnisha (Head Bun) of the Leshan Giant Buddha

AbstractThe Leshan Giant Buddha’s ushnisha (Head Bun) has suffered from loss of lime plaster, cracks, and biological damage, compromising its structural integrity and reducing the effectiveness of the drainage system in the Buddha's head. The infiltration of moisture has led to water damage within the statue, significantly accelerating its weathering. This situation urgently requires protection and reinforcement measures. Detecting deterioration in the ushnisha is a crucial step in the preservation process. In this study, we utilized two deep learning models for pixel-level semantic segmentation of the damage. Due to the small size of the cracks, a weighted loss function was applied to improve both the training speed of the model and the efficiency of crack identification. This weighting strategy proved effective for both models. The weighted K-Net model achieved a mean accuracy (mAcc) of 90.23% and a mean intersection-over-union (mIoU) of 69.55%, with a damage segmentation speed of 7 images per second, which is 1309 times faster than manual segmentation. By applying the trained deep learning models to re-examine the ushnisha, we successfully identified damage that had been overlooked during manual annotation. Using the model’s enhanced results, we conducted a comprehensive quantification of the damage across all ushnisha and identified the most severely affected areas. Additionally, we performed a model interpretability analysis to explain the decision-making process and principles of the deep learning models. This research provides significant practical value for detecting and quantifying damage in the Leshan Giant Buddha.

Identifying construction technologies and environmental connections at the Iron Age IIA settlement of Kh. es-Suwweida, Israel: A microarchaeological study

The first season of excavations at Kh. es-Suwweida in northern Israel revealed strata from the late Iron Age IIA consisting of a series of massive fortification walls, rooms and internal compartments with potential floors. A microarchaeological investigation was undertaken to add high-resolution contextual and compositional data to the field evidence and characterize site formation processes, construction materials and technologies, and use of environmental resources. We applied a micro-archaeological approach to study sediments and archaeological materials via micromorphology, Fourier-transform infrared (FTIR) spectroscopy and micro-spectroscopy, and phytolith and pollen analysis. Two main construction technologies were identified: lime plasters produced from mixtures of pyrogenic lime and non-pyrogenic crushed chalk, and mudbricks prepared from sedimentary materials. An in situ lime constructed floor with multiple re-plastering and activity zones associated with the remains of a degraded mudbrick structure was reconstructed in one locality, and a collapsed burnt lime and mudbrick building with a wooden superstructure was reconstructed in another locality. The micro-archaeobotanical analyses identify domesticated barley, the cultural utilisation of grasses on-site, and a hinterland vegetation of open fields. The combined microarchaeological evidence enables a more detailed reconstruction of the variability in construction technologies and the sequence of collapse and degradation processes in an Iron Age settlement.

Application of colloidal calcium hydroxide nanoparticles for consolidation of damaged lime plaster in historical buildings

Application of colloidal calcium hydroxide nanoparticles for consolidation of damaged lime plaster in historical buildings

Degradation Mechanisms of Mortar and Plaster Layers.

This article presents a case of complex investigation of defects of lime mortar and plaster that have been developing over a period of 48 years in a house in Prague and are strongly influenced by thermal and salt crystallization cycles. The aim of this research was to describe the degradation phenomena of mortars and plasters observed on a narrowly limited part of the building, combining structural elements of different types and ages and to explain the mechanisms of their formation and development. The geometric characteristics of the defects were determined by non-destructive methods, especially optical interference moiré, laser profilometry, photogrammetry, and infrared thermography. Material data were determined on samples by electron microscopy, ion exchange chromatography, and direct moisture content measurements. The results supported the hypothesis of the increase in the deformation of large buckles of detached plasters by the mechanism of buckling caused by loading of the edges with compression generated by volume changes. Direct loading of the boundary surfaces causes the formation of bulges in the confined areas. This study shows the importance of failure analysis of real structures to gain knowledge about the behavior of structures and materials under long-term service conditions.

Blended lime plasters with biomass ash and natural fibres reinforcement

Abstract The possibility to valorise biomass combustion ash in air lime based plaster was evaluated by means of mechanical properties. The possible effect of vegetable fibres (hemp, flax) was examined as well. The biomass ash improved significantly the mechanical properties of plaster. On the other hand, the vegetable fibres are limiting the compressive strength due to lower wettability between fibres and lime. However the fibres had positive effect on bending strength, as it is expected. The surface modification of fibres seems to be necessary in order to improve their performance in the lime system.

Analyzing the environmental impact of conventional wooden and modern reinforced concrete construction systems

Abstract Anatolia is a homeland for many traditional construction techniques due to its rich historical background. One such technique is the hımış system, which involves filling a wooden frame with masonry material (brick, stone, and adobe). This construction method, commonly found in Anatolia, represents one of the most prevalent types of traditional houses. However, with the increasing adoption of reinforced concrete systems in modern construction, Anatolia’s buildings are now being constructed with concrete systems. This paper aims at comparing the embody energy use and carbon emissions of the traditional hımış system, compared to modern reinforced concrete systems. The findings of the study suggest that the total embodied energy per m2 of wall space in modern structures spans from 3000 to 1700 MJ/m2, in contrast to traditional structures where it ranges between 1200 and 300 MJ/m2. Furthermore, the range of total embodied carbon emissions in modern buildings is observed to be between 320 and 120 CO2kg-eq/m2, while in modern structure systems, it varies from 150 to 20 CO2kg-eq/m2. This inconsistency underscores the environmental advantages of traditional building techniques over their modern counterparts in terms of both embodied energy and carbon emissions. The relative share of concrete significantly affected the results for modern systems, while the presence of lime plaster increased the environmental impacts of the hımış systems.

Valorization of waste wood fly ash in environmentally friendly lime-based plasters with enhanced strengths for renovation purposes

Waste wood fly ash (WWFA) generated during wood chips combustion in a power plant does not have any application nowadays and is commonly disposed of or landfilled. Nevertheless, considering its composition and reactivity in the presence of calcium hydroxide, it is one of the promising materials that could be used as an active admixture for modification and partial replacement of lime in lime plasters. This solution seems to be a suitable step to both improve the properties of the traditional lime plaster and reduce carbon dioxide emissions. Therefore, this comprehensive study describes a wide range of properties of lime plaster with WWFA (up to 50 wt% lime replacement) as an active admixture. Compositions of studied plasters were firstly analyzed with the help of XRD, DSC, and SEM, and then the effect of WWFA on the physical, mechanical, hygric, and thermal properties was investigated. The obtained results showed that the application of WWFA led to lower total porosity, highly improved mechanical properties, higher thermal conductivity, and lower water transport capability, which could be attributed to its pozzolanic activity. The performed experiments fundamentally broadened the existing insufficient knowledge about the utilization of WWFA for lime-based plasters improvement. All tested lime-based plasters (with 10, 20, 30 and 50% lime replacement by WWFA) have a high potential for common use in practice, especially in the historical buildings renovation. The originality of this paper lies, among others, in using a specific type of fly ash (originating from waste wood, not coal) and in testing a wider range of characteristics and properties of designed lime-based plasters with WWFA with respect to their changes over time, which enables prediction of plasters' durability.

Functionalization of lime mortars and plasters: A biomimetic approach

Lime mortars and plasters have been used as building materials since the origins of pyrotechnology in the Levant ca. 12,000-14,000 years ago, and currently are experiencing a revival as compatible and sustainable materials in heritage conservation and modern construction. Extensive research has recently explored ways to improve their properties, particularly using Nature as an inspiration. Such a biomimetic approach is enabling the functionalization of lime mortars and plasters via different strategies that are reviewed here and include accelerated setting via enzymatic-like catalyzed carbonation, increased toughness via inter- and intracrystalline additive incorporation, modification of surface wettability and enhanced self-cleaning ability via surface microtexturing and photoactive nanoparticle incorporation, anti-biofouling capacity, increased radiative cooling, or self-healing properties.

Development of lime injection grouts for the stabilisation of detached lime plasters with wall paintings in the unique Romanesque round church in Slovenia

This paper presents the design of lime grouts to stabilise wall paintings from the 13th and 14th centuries in the Romanesque church of St. Nicholas in Selo, Slovenia. Most of the paintings were executed using the secco technique on a single layer of lime plaster made of slaked lime and quartz sand, which was applied to a clay brick masonry base. The thickness of the detached pockets was generally 2 mm to 1 cm, in a few places up to 5 cm, especially in the vault area. Consolidation of detached plaster layers is an irreversible treatment to restore the adhesion between the detached plaster layers. It was therefore important that the grouts met certain criteria in terms of composition and properties in the fresh and hardened state. We developed three grouts that meet general criteria and two specific key requirements, such as low density and sufficient injectability without pre-wetting to prevent new damage and/or the plaster falling off the wall or ceiling during or after the consolidation treatment. The grouts consist of hydrated lime, fillers, polycarboxylate ether superplasticizer (PCE) and water. During the design process, various quartz fillers were tested in different proportions. The reduced density of the grout was achieved by using expanded glass granules as a partial filler substitute. The appropriate injectability of the grout was achieved through the combination of reduced water content and superplasticizer PCE.

Assessment of reinforced overlay for masonry retrofitting: Lime vs cementitious plaster

Reinforced overlay is a very common retrofitting technique adopted in existing masonry buildings to improve their performance under seismic action, both in-plane and out-of-plane. The most traditional and widespread approach considers the use of cementitious mortar as plaster with steel meshes as reinforcement. However, cementitious materials may raise compatibility problems with the base material and sustainability issues, thus the use of lime mortar should be preferred. This paper presents the results of an experimental program aimed at assessing the contribution of the reinforced plaster strengthening system in increasing the load carrying capacity of masonry walls, comparing the performance of cementitious and lime mortar plaster. Cyclic diagonal compression tests were performed under displacement control. Unreinforced specimens were also tested as reference for the improvement evaluation. The results showed an improved performance with respect to the unreinforced ones for both the materials (cementitious and lime mortar), in terms of both strength and deformation capacity. The peak load seemed to be not significantly affected by the type of plaster, while higher displacement at the ultimate load was observed in case of lime mortar. Finally, an analytical method formulated to predict the strength of walls retrofitted with cementitious reinforced plaster was applied to check its validity also in case of lime-based plaster.

РЕОЛОГИЧЕСКИЕ СВОЙСТВА ИЗВЕСТКОВЫХ СОСТАВОВ С ДОБАВКАМИ ПОЛИСАХАРИДОВ

Lime compositions with polysaccharide additives are being studied. The results are aimed at creating a new lime plaster composition with improved performance properties. Materials and methods. Standard methods for studying rheological and technological properties were used. Results. The influence of polysaccharides on changes in the rheological properties of lime compositions has been established. It has been established that the introduction of a polysaccharide additive (hydroxyethylcellulose) helps to accelerate the development of plastic strength. The results of infrared spectroscopy indicate a higher content of calcite in the sample with the addition of polysaccharide. The absence of chemical interaction between lime and polysaccharides has been established. Conclusions. The introduction of polysaccharide additives promotes the formation of a structure that improves the performance properties of the lime composite.

Material Characteristics of Lime Plaster in Goguryeo Mural Tombs (I): Focusing on Lime Plaster Excavated from Anak Tomb No.3

Physical and chemical investigations were conducted on lime sample from Anak Tomb No.3 to determine the properties of the plaster material. The morphological and physical characteristics of the specimens were analyzed using both a microscope and a polarizing microscope. The constituent materials were identified through X-ray diffraction and scanning electron microscope-energy dispersive spectrometer, and the qualities of the mixed material were established through thermal analysis. Additionally, micro-computed tomography was used to non-destructively confirm the internal structure and density characteristics. The lime sample was recognized as a lime plaster material with two unique layers. Each layer shows variations in material properties. It is speculated that this lime specimen was used to finish the edges of the authentic wall within Anak Tomb No.3. Through the synthesis of various morphological attributes and physical properties; the whiteness, durability, thinness, and repetition of the layers, as well as smoothness of the lime plaster used for Anak Tomb No. 3 indicate that a high level of lime wall plastering technique was used in Goguryeo Tomb. It was possible to evaluate the refined level of lime wall manufacturing technology in the Goguryeo era.

Super adsorbent bio-polymer additive to improve hygroscopic and acoustic properties of a conventional lime plaster

The paper introduces a new lime plaster composition, with a Super Bio-Polymeric Adsorbent (SABP), for interior applications to improve hygrothermal and acoustic comfort. Alginate SABP is added to a conventional lime plaster to improve hygroscopic and acoustic performance. The hygrothermal and acoustic properties of the modified plaster are compared with the ones of the original plaster with a preliminary moisture uptake test, the evaluation of the sorption isotherm, the moisture buffering value (MBV), and the acoustic absorption. The results show a significant increase in the equilibrium moisture contents and the MBV (from 0.7 to 6.2 g/(m2⋅%RH)). At the same time, the sound absorption coefficient is slightly improved, increasing 0.1-0.2 at frequencies higher than 500 Hz compared to the reference conventional lime plaster. The paper describes the material characterization: the sorption isotherm and the MBV are obtained using a dynamic vapor sorption (DVS) analyzer. The acoustic absorption is measured using the impedance tube method.

Decoding of lime-based binder materials of ancient vernacular Chettinad constructions in Southern India through microanalytical characterization

Vernacular Chettinad lime binder is widely popular in Southern India because of its quality in terms of durability over centuries and the fine glossy finishes attainable. However, its manufacturing technique concerning raw materials, the application process, and resultant characteristics are not explored or documented. The present study attempts to explore the mix compositions and application strategies of Chettinad lime plaster and mortar by characterizing samples collected from two ancient structures approximately 100 years old and in intact condition. Like any Chettinad constructions, the plaster in both buildings constitutes a base coat (coarser as observed) and a superior smooth glossy appearance finishing layer. The plaster samples collected from various locations from the two sites were thoroughly characterized for their physicochemical properties, microstructural characteristics, surface properties, mineralogical compositions, porosity, and pore size distribution. Analyses of the plaster samples suggest that the air lime and locally available, river-based siliceous aggregates were utilized as binder and aggregate, respectively, in ratios ranging from 1:1.51 and 1:2.57 in each of the buildings studied and correlated the ratio to their durability performance as well. Shell lime and organics such as curd and egg white were utilized to obtain the glossy plaster finish. The art of manufacturing and application of such a durable indigenous binder system is lost, not continued, and undocumented. The present study would act as (i) documentation that aids the continuation of the technique of the traditional binder production, as well as (ii) decoding the compositional differences of the plaster and mortar at various locations/applications, which would help in properly maintaining and restoring degraded portions of building structures by reproducing similar and compatible material.

Development of a Single-Sided Magnetic Resonance Surface Scanner: Towards Non-Destructive Quantification of Moisture in Slaked Lime Plaster for Maintenance and Remediation of Heritage Architecture

Single-sided time-domain proton magnetic resonance (MR) surface scanners are useful for non-destructive measurements of moisture. A mobile single-sided MR sensor unit employing two concentric ring magnets was constructed for the in situ quantification of moisture in slaked lime plaster used in the outer walls and roofs of heritage architecture. This sensor unit allows for non-destructive measurements of water proton relaxation 1.5 to 13.5 mm beneath the surfaces of walls and roofs. The following laboratory experiments on water-saturated porous slaked lime plaster samples were performed. (i) The porosity (water volume fraction) was measured in approximately eight minutes with a root mean square error of 1.9 vol%. (ii) The fundamental MR-related property (i.e. proton surface relaxivity) needed for the estimation of the pore size distribution was also measured successfully. (iii) The pore volume expansion due to frost damage was successfully detected as a significant change in the transverse relaxation time distribution. These results demonstrate that the portable MR surface scanner is a promising non-destructive testing tool for the maintenance and remediation of heritage architecture made of plaster.

Semantics of the Tsyrt-Obelisk of the Sacred Mihdau Reserve

The proposed article is devoted to the study of the semantics of tsyrts – vertical slabs dug into the ground-steles, of varying degrees of processing, or obelisks built of stone, which collectively date from the Late Middle Ages to the beginning of the XX century. Until recently, it was believed that all of them are funerary or memorial in nature, but recent studies have shown another purpose of these monuments. Part of the tsyrts-steles was erected to delimit the territory - both sacred spaces and farmlands. The conclusions made are confirmed by folklore materials and linguistics data. Of particular interest is a small group of early tsyrts-obelisks, the semantics of which has not yet been studied. Almost all of them are laid out of treated stone on lime mortar and covered with lime plaster or coating. They are located in cemeteries, near temples or in an open area. The analysis of these monuments allows us to conclude that their semantics are in the paradigm of the three-level Indo-Iranian worldview, characteristic of the Scythian-Alanian tradition. The examination of one of the most striking monuments of this type, the tsyrt-obelisk of the sacred reserve of Mikhdau (Ursdon village, Alagirsky district of the RNO-Alania), showed that in the hierotopia of this religious complex, this tsyrt symbolizes the heavenly gatekeeper, located on the border between the human and celestial spheres, on the way of worshippers to the temple. The reserve itself is marked with a three-stage rock, symbolizing the World Mountain.

Enhancement of the hygroscopic and acoustic properties of indoor plasters with a Super Adsorbent Calcium Alginate BioPolymer

The present study introduces a novel-composition lime plaster that contains a Super Adsorbent BioPolymer (SABP) based on Calcium Alginate (CaAlg) for indoor applications, to improve hygrothermal and acoustic comfort. The sorption isotherm of the plaster, the moisture buffering value (MBV), the acoustic absorption, and the thermal conductivity have been assessed. The hygrothermal and acoustic properties of the modified plaster have been compared with those of the original composition to evaluate its performance under different concentrations of CaAlg (between 10 and 30% wt). Adding the CaAlg SABP to a conventional lime plaster consistently enhanced its hygroscopic properties. The results show a substantial increase in the equilibrium moisture uptake (between 10 and 23 fold) and MBV, from 0.9 to 9.3 g/(m2⋅%RH). The sound absorption coefficient improved by 0.1–0.2 at higher frequencies than 500 Hz. This paper provides detailed information on the characterization of the material. It includes details about using a dynamic vapor sorption (DVS) analyzer to evaluate the sorption isotherm and MBV. It also contains information on the impedance tube method used to measure the acoustic absorption of the material.

Petrographic and Chemical Characterization of the Frescoes by Saturnino Gatti (Central Italy, 15th Century)

This study presents the petrographic and chemical characterization of the frescoes in the Church of San Panfilo in Tornimparte (AQ, Italy) by Saturnino Gatti, a prominent painter of the late 15th–early 16th century, known for his exquisite technique, composition, and use of color. The characterization of the frescoes is essential for understanding the materials and techniques used by Gatti, as well as for identifying the stratigraphy and painting phases. Eighteen samples were collected from the original paint layers, later additions (17th century), and restored surfaces, and analyzed by optical microscopy, cathodoluminescence microscopy, scanning electron microscopy (SEM-EDS), μ-Raman, and electron paramagnetic resonance (EPR). The analyses revealed a microstratigraphy often made of three main layers: (1) preparation, consisting of lime plaster and sand; (2) pigmented lime, applied by the fresco technique; and (3) additional pigmented layer on the surface. The most often recurring pigments are black, red, yellow (all generally linked with the fresco technique), and blue (applied “a secco”). The presence of two painting phases was also noted in one sample, probably resulting from a rethinking or restoration. These findings contribute to the understanding of the history and past restoration works of this cultural heritage site, providing important insights not only for conservators and restorers, but also for a broader understanding of Italian fresco painting and art history of the late 15th and early 16th centuries.

DESTRUCTION OF POLYMERCEMENT PLASTER COATING DURING OPERATION OF WALL STRUCTURE

The disadvantage of limesand, limecement and cementlime plaster mortars is the intensive formation of cracks during hardening and operation, which leads to rapid destruction of the plaster coating, its detachment from the masonry, which causes increased humidity and loss of heat through it, as well as reducing the service life of the wall structure.The main reason for this is choosing the components of the mixture and their quantity without taking into account the processes occurring during curing of the coating and its "work" as part of the wall structure during operation.To solve the problem, the wall structure should be considered as a system that includes a plaster coating associated with the masonry through the contact area. The composition of the soluble mixture must be prescribed taking into account the processes occurring during its hardening and operation of the wall structure, the stresses that occur in it. It is necessary to choose the components of the mixture and their quantity, so as to ensure the reduction of stresses in the plaster coating and its contact zone with the masonry, to values, less than destructive. This will increase the service life of the coating and wall construction.Since the properties of polymercement plaster mortar are determined by its composition and structure, to achieve these goals, the possibility of managing them by purposeful selection of components of the soluble mixture was analyzed. For this purpose, redispersible polymer powders (RPP), polymer fiber, cellulose esters, and a fine filler with a low modulus of elasticity were used.Studies have shown that their use has changed the nature of the destruction, reduced the number of cracks formed during the hardening of the plaster mortar, slowed down their development and increased the service life of plaster mortar and the wall structure.