Durability Properties of Innovative Plasters for Renovation of Historical Buildings (original) (raw)
Related papers
Construction and Building Materials, 2012
An extensive set of parameters of several lime-metakaolin plasters, including basic material characteristics, mechanical and fracture-mechanical properties, durability characteristics, hydric parameters and thermal properties, is presented. In a comparison with the reference lime plaster without any additives, the experimental results show three-to five-fold increase in strength, about 25% decrease of water vapor diffusion coefficient, 20% decrease of water absorption coefficient and a very high increase of freeze/thaw resistance. Using the lime of very high purity in lime-metakaolin plasters (98.0% of CaO + MgO) is found preferable to lower-purity limes; the main differences are observed in the freeze/thaw resistance, mechanical and fracture-mechanical parameters. A comparison with two commercial renovation plasters shows that the only notable advantage of the best commercial plaster studied over the best lime-metakaolin plaster is in its lower moisture diffusivity but it can be matched relatively easily by using hydrophobization admixtures. Therefore, it can be concluded that the lime-metakaolin plasters can find a wider application range in the renovation of historical buildings in the future and may at least partially replace the current renovation plasters as a cheaper and equally effective solution.
Historical plasterwork techniques inspire new formulations
Construction and Building Materials, 2013
Lime putty, gypsum, rabbit skin glue, sand, limestone fines and marble dust were used. 100% Substitution of sand by limestone fines of an ''Escaiola'' is studied for the first time. Marble cut waste in mortar increases the strength and durability.
Turkey is quite rich with historical buildings. Depending on various factors like time, increasing air pollution due to technological improvements of the present era together with insufficiency of inspection leads to the formation of damages on these buildings which are part of our historical heritage. Conservation of such buildings which are as important as historical documents should be the first and foremost target of any project. Where maintenance is insufficient, conservation and restoration attempts should replace it. What is necessary in restoration is the use of material which resembles the original material to the closest degree or, producing appropriate material which is compatible with the properties of the original material. The first dimension of the current problem is the insufficiency of resources while the second dimension stems from the lack of proper evaluation of the material to be used in conservation and restoration. This study defines the importance of mortars and plasters along with their history and the reasons of deterioration. In addition, it sets up the information flow of mortar and plaster within a systematic decision making process. The necessary experimental methods for the production of new repair mortar or plaster that can be used in determining the character analysis of original mortar and deterioration morphology are also analyzed. Thus, a method that can be used in the conservation and restoration studies is determined with this paper. r
Sustainability, 2021
Coatings and plasters are an integral part of masonry cladding, having a fundamental protective and aesthetic function. They are exposed to numerous aggressive actions, which produce their degradation over time. The utilization of lime, as a binder in masonry lining mortars, plays an important role in their durability and conservation. The objective of this work is to analyze the fresh and durability properties of lime-based mortars for their application in the restoration of old buildings. Four different kinds of mortars were studied with similar workability, using as binders lime putty, aerial lime, and hydraulic lime. The aggregates used consisted of sand and crushed rock powder. As fresh properties, the consistency (by using the flow table) and water retentivity were determined. With respect to durability-related properties, water absorption by capillarity and by immersion, drying kinetics, and carbonation depth were studied. Bulk density and porosity of the mortars were also ob...
International Journal of Architectural Heritage, 2019
In a previous study, a layer of limewash was detected over the gypsum plasterworks used to decorate different spaces of the Real Alcázar of Seville such as interior rooms, patios and outdoor galleries. In this paper its use is analysed, namely whether it improves the properties of the plasterworks and provides a protective effect, through accelerated weathering tests designed specifically to reproduce real environmental conditions. Plaster specimens with similar composition and physical characteristics to those of the original plasterworks were prepared. After the cure of the specimens, the application of a layer of limewash was made. Samples were subjected to weathering tests that consist of water absorption cycles (by capillarity and immersion) and drying. The results showed that the application of limewash did not improve the durability of the plaster significantly, although seemed to have a more protective effect against weathering by capillarity tests in the specimens prepared with a higher water/plaster ratio. In fact, after the immersion tests a great part of the limewash layer became detached, while in the plasterworks of the Real Alcázar this behaviour has not been observed. So, capillarity tests seem to be more adequate to reproduce the real weathering conditions of these ornamental elements.
The study of the composition of mortars used in the protection of walls and ceilings in the past is extremely important to define sustainable strategies of intervention, concerning the preservation of these construction elements. These strategies should follow the modern theories of conservation and restoration , where authenticity and chemical, physical and aesthetic compatibility can only be achieved if based on the knowledge of the original materials and techniques of application. In Portugal, the presence of gypsum plasters was particularly significant between the second half of the XVIII century and the first half of the XX, representing two centuries of important heritage never studied before. This paper describes and discusses a methodology to establish compatibility criteria for the development of gypsum plaster restoration products and presents some requirements they should comply with based on the results of characterization of the old samples collected, from several case studies.