In this paper, the process of design and evaluation of compatible materials to partially or completely substitute damaged interior walls and ceilings coatings made of gypsum-based plasters is ...presented and the results obtained are discussed.
The methodology used comprised the definition of quantitative requirements to be accomplished by the new materials, based on previous works of the authors with characterization of an extensive set of samples of historic buildings. It was concluded that there is need to develop three different restoration materials, one for each family of plaster elements: thin-layer finishing plasters (L), elements moulded on site (M) and precast decorative elements (P).
The physical and mechanical properties of seven mixes based on gypsum and lime, with addition of other components, were determined and allowed concluding that the binder proportions (gypsum: lime) is the most influential factor. Higher gypsum content leads to stiffer materials, less shrinkage and higher absorption coefficients than in lime-based mixes. The formation of micro cracks was pointed out as a possible cause for the decrease of flexural strength and water vapour permeability values of the M mixes.
The comparison of the results obtained with the compatibility requirements allowed finding well-suited restoration materials for thin-layer coatings and precast elements. The mixes for moulded on site elements revealed to be the less balanced, and some adjustments are advised.
•Adequate methodology allowed the development of compatible restoration materials.•Solutions for thin-layers (L), moulded on site (M) and precast (P) plasters are proposed.•Gypsum and gypsum-lime based repair mixes are defined and characterized.•The binders proportions greatly influence the physical and mechanical properties.•Compatible materials were found for L and P elements; M mixes need further settings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Animal glue increases weathering resistance of lime-based materials.•Animal glue reduces crack formation upon drying of plasters and improves adherence.•Formation of an organic/inorganic hybrid ...material in the presence of animal glue.
In order to optimize lime plasters for conservation purposes, the influence of animal glue on the mineralogical evolution, mechanical properties, and weathering resistance was studied. The organic additive caused a decrease in carbonation rate and affected mechanical properties negatively, facilitating the formation of large air bubbles in the plaster matrix. However, the weathering resistance (water spraying/SO2 exposure) improved significantly. The organic additive also reduced crack formation and formed a physical barrier around the calcite crystals, which delayed sulfation. Lime-based composite materials are a valuable alternative to conventional lime plasters, showing improved adherence to the substrate and no significant color changes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Quality of Lime plaster floors improved at Holmul during Late Preclassic period.•SEM-EDS and pXRF utilized to identify barite in fine-plaster layer of plaster floors.•Discussion regarding whether ...barite found in floor samples was intentional or unintentional decision.
This article investigates lime plaster composition and floor construction at the ancient Maya center of Holmul in northern Guatemala during the Late Preclassic period (400 BCE – 250 CE). The mineralogical and chemical composition of these lime plaster floor samples were obtained through the analysis of thin sections via Polarizing and Optical Microscopy, SEM-EDS, and portable XRF. Examination of these archaeological plasters determined that significant improvements were made to the lime plaster technology at Holmul during the Late Preclassic period and were accompanied by the incorporation of barite into the lime plaster. This research also revealed the early utilization of alternative materials for floors in civic-ceremonial centers, as one floor sample was composed of clay plaster and another of a compacted sascab. Finally, by building upon prior plaster studies conducted at neighboring centers, this article provides a better understanding of plaster production in the Cival region. It also offers insight into a potential local tradition involving the addition of barite to the lime plaster at the sites of Cival, Holmul, and San Bartolo.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Determination of temperatures of calcination in lime pit-kilns.•Setting up a heating temperature calibration curve by FTIR-ATR.•Definition of lime or limestone in the manufacture of Mayan ...floors.•Archaeological evidence of lime production in the Mayan area.
A controlled heating experiment has been carried out on selected geological limestone samples obtained from the Yucatan peninsula to establish a heating temperature calibration curve for the determination of heating temperatures through Fourier Transform Infrared Spectroscopy (FTIR-ATR) ratios of υ2/υ4 peak intensities. This curve – the first produced in the Mayan area – will greatly benefit the study of the lime calcination technology employed by the ancient Maya society. This model was then applied to the study of an archaeological pit-kiln located on the northern Maya lowlands, allowing us to describe the temperature distribution at which the limestones were exposed within the structure, and consequently providing insights on the lime manufacturing process and the control of fire achieved by this culture.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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.
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•Applicability of waste wood fly ash (WWFA) at the design of renovation plasters is analyzed.•WWFA greatly improves strengths and reduces CO2 emissions of lime plasters.•Carbonation and pozzolanic reactions are active for at least six months.•Thermal conductivity increases with the increasing share of WWFA.•WWFA significantly reduces water transport parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study characterizes the thermal, chemical, mineralogical, and microstructural properties of the materials in a historic building. The case walls, located in the historic hub of Karachi, ...Pakistan, are almost 100 years old and in danger of losing their originality due to the deterioration of the materials. Eleven locations are identified with the help of a thermograph analyzer, and samples consisting of stone, mortar, and plaster are collected for characterization. The analysis is carried out by employing X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Either calcite or calcium carbonate is found in large quantities in all samples, along with quartz, which is found in significant quantities in the mortar and plaster. The identification of quartz reveals the presence of aggregates in mortar and plaster binder. Moreover, the chemical characterization identifies samples as lime mortar and plaster with high and moderate hydraulicity. Similar results are reported through XRD and TGA, with additional findings of gypsum and portlandite. The appearance of the latter-mentioned minerals, along with calcite, dolomite, feldspar, brucite, and quartz, are verified through microstructural characterization. Moreover, using SEM images, the aggregate size is evaluated, with the presence of medium-to-coarse sand identified in the mortar, and fine-to-medium sand found in plaster. A binder to aggregates was estimated as 1:2.5 for mortar and 1:4.5 for plaster through CaCO3/ SiO2 ratio.
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Plasters containing lightweight aggregates are mostly characteristic by low bulk density and low thermal conductivity but these favorable properties are often achieved at the expense of mechanical ...strength. In this paper, lightweight lime-based plasters are designed which have good thermal and mechanical properties at the same time. As their supposed applications include the renovation of surface layers of historical buildings, burnt clay shale is used as pozzolanic admixture to lime. The volumetric ratio of silica sand and expanded clay aggregate (ECA) is varied over a wide range to analyze the effect of ECA on microstructure, texture, and mechanical, thermal and hygric parameters of investigated plasters. The microstructural studies show a more compact interfacial transition zone between the basic lime-pozzolan matrix and ECA, as compared with silica sand, which is the most important factor affecting the properties of studied plasters. Apparently, the surface roughness of ECA grains at first makes possible easier formation of hydration products and later it can support the growth of calcite crystals and CSH amorphous phases. The textural analysis together with the measurement of basic physical properties reveals, as the second principal factor, a substantial increase of open porosity with the increasing ECA dosage; the added pores are mostly within the range of 10 nm to 1 μm. The assessment of the wide range of engineering properties of designed plasters leads to the identification of the lime-pozzolan plaster with the volumetric ratio of 1: 1 between silica sand and ECA as the most appropriate solution. The thermal conductivity of this plaster is two times lower than of the lime-pozzolan plaster with silica aggregates, while the changes in compressive and bending strengths are only marginal. The favorable hygric properties can be considered as another asset. Faster water vapor transport, together with the higher water vapor adsorption capability, can decrease a risk of water condensation and moderate the effects of both exterior and interior climate, the relatively slow liquid water transport is a limiting factor for rainwater penetration. The economical parameters of the plaster with the best functional properties are also very good. According to the current situation on the Czech market, the price increase is only 3%, as compared with the reference mix.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Traditional buildings since many centuries have used lime as a binder and finishing material. However, in contemporary construction practices, lime mortar and lime plaster have been replaced by ...cement mortar and cement plaster. Lime is a sustainable and self-healing material whose strength increases with time. In addition to its pleasing appearance, lime has excellent moisture buffering properties. Buildings with lime mortar and lime plaster are also breathable due to moisture transfer across the envelope. The objective of this work is to compare the hygrothermal performance of lime and cement plaster. For this purpose, two identical test cells of 1 m3 volume were constructed with brick as masonry material. One of the test cells was built with cement mortar and cement plaster, while the other cell was made with lime mortar and lime plaster. Environmental variables such as indoor air temperature, indoor relative humidity, globe temperature, surface temperatures, surface moisture content were monitored for a period of 74 days. It was found that the lime test cell was cooler by 3–5 °C and the indoor conditions were comfortable for 40% more time. The moisture buffering capacity of lime also helped to moderate the indoor relative humidity. The above differences were observed when the test cells passively responded to the changing outdoor conditions without internal loads. Further investigation of real-sized spaces would be necessary to endorse the advantages of lime plaster found in this study.
•Lime and cement plastered test cells monitored for a period of 74 days.•Lime plaster reduces indoor temperature by 3–5 °C and moderates relative humidity.•Comfort hours in lime test cell higher by 40%.•Hygrothermal properties of lime and cement plaster have been reported.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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