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The service life of repair plasters is affected by many factors. Salt crystallization is one of the most important, especially in case of plasters intended for repair of salt laden masonry. To predict the durability of plasters, the accelerated laboratory salt crystallization tests are usually used. However, there is still no standard commonly accepted methodology for evaluating the durability of plasters with regard to salt damage. In this paper, the investigation of sodium chloride (NaCl) crystallization in three lightweight repair plasters is presented. Plasters were subjected to an accelerated laboratory salt crystallization test, which consisted of cyclic drying and wetting with using of NaCl solution. Studied materials were two cement-lime plasters and one gypsum-lime plaster, all lightened by the addition of expanded perlite in order to enhance their thermal insulation parameters. The characterization of plasters before drying-wetting cycles included measurement of specific density, bulk density, total open porosity, compressive strength, flexural strength, and dynamic modulus of elasticity. The evaluation of salt crystallization resistance was determined by means of scanning electron microscopy (SEM) investigation and compressive strength ratio before and after salt crystallization test. Based on the results obtained, the developed plasters can be recommended for use as a material in the repair of the salt laden masonry. [ABSTRACT FROM AUTHOR]

The selected ashes were tested to analyse the possibility using them as admixtures that can improve the durability of lime plasters with respect to salt crystallization and freeze/thaw resistance. Coal fly ashes and biomass-based ashes were characterized by their chemical and physical properties. Pozzolana activity was also determined using Frattini and Chapelle methods. The samples were different from each other by specific surface, particle size distribution, and chemical composition. All tested ashes can find use as pozzolana active admixtures with power to enhance durability of lime-based plasters that might be used in repair of historical masonry, rendering and plastering materials. [ABSTRACT FROM AUTHOR]

This paper focuses on the experimental testing of hydrated lime-, natural hydraulic lime-, and lime-cement-based mortars with improved salt accumulation capacity. Moreover, the effect of varying content of non-hydrophobised expanded perlite (EP) in the mortars on their durability was investigated. The substation of silica sand by expanded perlite was 25%, 50%, 75% and 100% by volume. A modified method based on the adsorption of free salt ions from solution was used to measure the chloride binding isotherms. The salt concentration was analyzed using an apparatus working on liquid chromatography technique. The data acquired were compared with reference mortars with natural silica sand as an only aggregate. The use of expanded perlite significantly increased the chloride binding capacity of the tested mortars, while no deterioration was observed for samples contaminated with salts. The results obtained thus validated the applicability of most of the mortars tested for the repair of masonry structures including the restoration of renders and plasters. When repairing historic masonry, compatibility issues must be considered, in this case with respect to the type of binder used. [ABSTRACT FROM AUTHOR]

Unsatisfactory environmental impact on old building operation leads to an effort to amend renovation and restoration process pointing to the reduction of energy consumption caused by heating and cooling. Large part of historical building envelope is represented by valuable highly decorative facades with insignificant thermal insulation function. The necessity to reduce heat transfer via building envelopes while maintaining aesthetic values of historical decorative facades is enables application of renders with improved thermal insulation performance. However, the newly developed materials for facade repairing must be compatible with the old ones, originally used in the past. In this study, natural hydraulic lime-based plastering mortars were tested. Natural silica sand (SA) used in the reference samples was replaced by an expanded glass granulate (EG) in the selected volume ratio. The basic structural properties and thermal properties in dependence on moisture content were studied. The results show considerable drop of thermal conductivity values with the increasing share of EG aggregate. The developed materials were categorized in accordance with the thermal insulation plasters standards as the thermal insulation mortars of T2 type. [ABSTRACT FROM AUTHOR]

The aim of the presented work was to develop and evaluate the novel thermal insulation plaster intended for repair and renovation application. The thermal parameters of the reference lime plaster were enhanced with the substitution of 50 vol. % of silica sand with expanded perlite. The hardened plasters were characterized by their specific density, bulk density, total open porosity, compressive strength, flexural strength, and dynamic modulus of elasticity. The thermal conductivity and the volumetric heat capacity were investigated as well. As the studied plasters should find use in repair of salt-laden masonry, the specific attention was paid to the assessment of their durability in terms of resistance to salt damage. Plasters were subjected to the accelerated laboratory salt crystallization test that consisted of ten wetting/drying cycles, where the used salt was sodium chloride. For comparison, the same process was performed with distilled water. The salt crystallization resistance was evaluated using the photographical observations and the measurement of the residual compressive strength. The results obtained showed that the use of expanded perlite allows the development of the lightweight repair plaster with sufficient mechanical parameters and improved thermal insulation properties. Moreover, the high porosity of lime-perlite plaster has contributed to its great durability against salt crystallization. [ABSTRACT FROM AUTHOR]

Natural zeolites having a structure with a large number of cavities allow design lightweight plasters with improved thermal insulation parameters. Focusing on the assessment of plasters’ durability, their resistance to salt damage should to be taken into consideration, especially in case of their application in repair of salt laden masonry. Although the crystallization of salts in plasters presents a serious problem, there is as yet no standard procedure for its evaluation. To predict salt damage of lime-based plasters in practice, they were subjected to accelerated laboratory salt crystallization test, where sodium chloride solution and cyclic drying and wetting were the observed degradation factors. Studied materials were lime plaster and lime-zeolite plaster, where zeolite was used as a full replacement of silica sand. A comprehensive characterization of both plasters performed before crystallization test cycles included specific density, bulk density, total open porosity, compressive strength, flexural strength, and dynamic modulus of elasticity tests. The assessment of salt damage was done based on the photographical observations, optical microscopy, and mass change after salt crystallization experiment. Obtained results of the plasters’ durability with respect to the salt resistance provided the necessary information for improvement of laboratory salt crystallization tests. [ABSTRACT FROM AUTHOR]

This paper deals with the properties of commonly used exterior plasters on thermal properties of construction. The surface spectral emissivity properties of acrylate, silicate, and silicon plasters and also the dependence on abrasiveness and the color were compared. [ABSTRACT FROM AUTHOR]

Bishop’s residence placed on hillock called Dómský pahorek, Litoměřice, Czech Republic, consists of a group of buildings of historical value. Today, some of the buildings are in bad technical conditions and require conservation and repair with respect to retain their cultural significance. It is situated on the hill where a historical settlement existed from 9 century. In baroque period the bishopric was founded in this area. Nowadays there is St. Stephen’s Cathedral, canon houses, consistory and provostery and the bishop´s residence with a group of farm buildings that shows excessive moisture and salt related problems demonstrated by degradations of plasters and masonry constituents. For the design and selection of effective repair techniques and treatments, detailed information on moisture and salt content in restored plasters and their substrate is necessary. Therefore, the hygric state and the rate of contamination with water soluble salts were examined in the paper in order to get relevant data for identification of possible moisture and salt sources and provide information for technical and historical condition survey of investigated historically valuable buildings. The obtained data will find use in the design and development of new types of repair mortars and plasters with improved resistance against coupled moisture and salt action. [ABSTRACT FROM AUTHOR]

Natural hydraulic lime-based plasters have been investigated with respect to the possibility of their use in the renovation of historical building facades. In order to increase porosity and thus improve some utility properties, expanded perlite was incorporated as a lightweight aggregate. To ensure that the parameters associated with liquid moisture transport did not deteriorate, the rate of NaCl solution penetration was measured and the moisture diffusivity for salt solution was calculated using the Boltzmann transformation method. It has been found that due to the increasing content of perlite in the material, the transport of salt solution was slightly accelerated what was in agreement with porosity and bulk density data. [ABSTRACT FROM AUTHOR]

Highly decorative facades are an essential part of old buildings, historical monuments respectively. Over time, these may be damaged by weathering or other harmful factors and thus must be retrofit or replaced. Facade, as an important component of building envelope, affects the overall energy demands necessary for heating and cooling of indoor space. In this context, this paper deals with the use of expanded glass granulate as a partial or full replacement of natural silica sand in composition of lime-based plasters and evaluation the effect of this alternative lightweight aggregate on final plaster properties. Researched parameters, such as basic structural properties and thermal properties in dependence on moisture content were determined for samples cured in the high relative humidity environment for 28 days. Conducted experimental tests revealed high thermal insulation ability of glass aggregate that also significantly helped to decrease unit weight of produced plasters. [ABSTRACT FROM AUTHOR]

Information on plasters hygrothermal performance is of the particular importance for their applicability, especially in such applications, where high moisture content of the substrate is anticipated. Among such applications belong above all historical and older buildings, where horizontal water-proof insulation is usually missing. Therefore, hygric and thermal properties of newly developed lime plasters modified with wood chips ash-based mineral admixture are studied in the paper. As wood chips ash is pozzolana active, in plasters composition, lime hydrate was partially substituted by wood chips ash coming from biomass incinerator for heat and electricity production. The replacement ratio was 5, 10, and 15 mass % respectively. The dosage of batch water was maintained similar for all tested plasters. For basic characterization of studied materials, their bulk density, specific density and total open porosity were measured. Among hygric properties, apparent moisture diffusivity, water absorption coefficient, saturation moisture content and water vapor transmission parameters were accessed. As heat transport and storage significantly affect plasters performance in a real environment, their thermal conductivity and volumetric heat capacity were measured. Since the total open porosity was almost similar for all tested plasters, and their hygric and thermal properties varied in dependence on lime hydrate substitution, additional pore size distribution measurement was performed for explanation of obtained data. Based on performed test and accessed data, wood chips ash was found to be an alternative eco-efficient mineral admixture applicable in plaster mix composition. [ABSTRACT FROM AUTHOR]

Biomass combustion represents a renewable energy source and helps to reduce carbon emission. As the amount of solid residuals from biomass combustion will increase in a near future, the newly designed lime-based plaster modified with pozzolana active biomass ash was studied in this paper. Reference lime plaster and plaster with 15% binder replacement by mass with wood chips ash (WCHA) were the subject of an extensive experimental campaign. As there was a reduction in mechanical parameters for plaster with incorporated biomass ash, a new plaster mix with reduced amount of batch water was designed and tested. To obtain detailed information on applied biomass ash, its chemical composition was measured by X-Ray fluorescence analysis (XRF), morphology was examined using scanning electron microscopy (SEM), and mapping was performed using energy dispersive spectroscopy (EDS) analyser. For the examined plasters, basic structural, mechanical, hygric, and thermal properties were accessed. As no deterioration neither in mechanical or in functional properties of the final newly designed plaster was observed, it can be concluded that biomass ash can find use in designing of plasters for renovation of historic facades. It is evident the use of biomass ash in the plaster designing brings both ecological and economic benefits as the incorporation of ash into the plaster mix composition reduces the cost of binder production, whereas also waste disposal finances are saved. [ABSTRACT FROM AUTHOR]

The building envelope is a principal responsible for buildings energy loses. Lime plasters as the most popular finishing materials of historical buildings and culture monuments influence the thermal behaviour as well as construction material of masonry. On this account, the effect of ageing on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime plaster is tested. The ageing is accelerated with controlled carbonation process to simulate the final plasters properties. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity are experimentally assessed using a transient impulse method. The obtained data revealed the significant changes of the both studied thermal parameters in the dependence on plasters composition and age. The assessed material parameters will be stored in a material database, where will find use as an input data for computational modelling of heat transport in this type of porous building materials and evaluation of energy-savings and sustainability issues. [ABSTRACT FROM AUTHOR]

Indoor air temperature and relative humidity represent important parameters for health and working efficiency of buildings occupants. Beside the moderation of temperature, investigation of hygric properties of building materials with connection to indoor relative humidity variation became recognized as a relevant factor for energy efficient building maintenance. The moisture buffer value introduced in the Nordtest protocol can be used for estimation of moisture buffer capacity of building materials or their multi-layered systems. In this paper, both the ideal and real moisture buffer values are examined on the basis of simulation of diurnal relative humidity fluctuations in plasters with incorporated PCM admixture. Retrieved data points to a complex effect of the tested plasters on possible moderation of buildings interior climate. [ABSTRACT FROM AUTHOR]

The carbonation process of prepared lime plaster and lime based plaster with pozzolana active metakaolin is performed in an accelerated test arrangement. The depth of carbonation head is determined using colorimetric method and FTIR spectroscopy. Based on experimental data of carbonation head, time dependent k factor function is calculated that points to the decelerated and retarded propagation of the carbonation process due to metakaolin used in plaster composition. [ABSTRACT FROM AUTHOR]

Two types of commercially produced plasters exposed to the real environmental conditions are studied in terms of measurement moisture transport parameters in the conditions of one-sided water uptake. The Boltzmann transformation method is used to process the data from measured moisture content profiles and the liquid water diffusivity is determined. For researched materials, the basic physical properties as bulk density, matrix density and total open porosity are measured in respect to their age and climatic loading. The obtained results point to the coupled disruptive processes taking place within the material exposure to the real central Europe environment, whereas the climatic loading leads to the significant acceleration of liquid moisture transport what is highly negative finding from the point of view of materials functionality and service life. [ABSTRACT FROM AUTHOR]

In recent years many new block of flats with parking garages placed inside the buildings were constructed. This tendency brings beyond question benefits for residents and also for city planning, but it requires new design and structural approaches and advanced material and construction solutions. The analysis of plaster damage on partition wall in parking garage in one of these buildings is presented in the paper. The damage of studied plaster is caused by the salts which are transported together with snow on cars undercarriage into garage area during winter. The snow melts and water with dissolved salts is transported by the capillary suction from concrete floor into the rendered partition wall. Based on the interior temperature, adsorbed water with dissolved chlorides evaporates and from the over saturated pore solution are formed salt crystals that damages the surface plaster layers. This damage would not occur if the partition wall was correctly isolated from the floor finish layer in the parking garage. [ABSTRACT FROM AUTHOR]

Lime plasters are the most popular finishing materials in renewal of historical buildings and culture monuments. Because of their limited durability, new materials and design solutions are investigated in order to improve plasters performance in harmful environmental conditions. For the practical use, the plasters mechanical resistivity and the compatibility with substrate are the most decisive material parameters. However, also plasters hygric and thermal parameters affecting the overall hygrothermal function of the renovated structures are of the particular importance. On this account, the effect of moisture content on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime and cement-lime plasters are tested as well. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity in the broad range of moisture content are experimentally accessed using a transient impulse method. The obtained data reveals the significant increase of the both studied thermal parameters with increasing moisture content and gives information on plasters behaviour in a highly humid environment and/or in the case of their possible direct contact with liquid water. The accessed material parameters will be stored in a material database, where can find use as an input data for computational modelling of coupled heat and moisture transport in this type of porous building materials. [ABSTRACT FROM AUTHOR]

A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM. [ABSTRACT FROM AUTHOR]

Experimental research on the effectiveness of renovation plasters for application on wet masonry containing water soluble inorganic salts is presented in the paper. Within the laboratory tests, measurement of basic physical properties, mechanical properties, thermal properties, pore size distribution, sorption isotherms and chloride binding isotherms are done for four types of renovation plasters in original state as well as for materials exposed to saturated solution of NaCl. The obtained results show the applicability of studied materials for renovation of building structures having excessive moisture and salt content. [ABSTRACT FROM AUTHOR]