Studies in ancient gypsum based plasters towards their repair: Physical and mechanical properties (original) (raw)
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In order to achieve the issues of compatibility for the design of new repair products a complete characterization of the original materials is of extreme importance. Gypsum plaster materials are not an exception to that rule. The characterization work of the Portuguese historical gypsum plasters has never been done as well as the study of efficient solutions for their preservation. In this paper the results of the characterization of gypsum plaster samples from the second half of the XIX century belonging to the Arabian Room of the Bolsa Palace, located in Oporto, North of Portugal, are presented and discussed. XRD, TGA-DTA, optical microscopy and FESEM-EDS observations were used for the chemical and microstructural characterization. Some physical properties, such as dynamic modulus of elasticity and capillary absorption were also determined. A relationship between the results obtained, namely composition and characteristics observed in the samples, and the technology associated to their use and application on site is established.
Methodology for the rehabilitation of ancient gypsum plasterwork
Journal of Building …, 2007
Hélder Cotrim is an Architect MSc in Construction from IST. His research is related with inspection, diagnosis and rehabilitation of ancient gypsum plasters. Maria do Rosário Veiga, Civil Engineer IST, received her Doctoral degree in civil engineering from Faculdade de Engenharia da Universidade do Porto (FEUP), and is a senior researcher in LNEC. She is the Portuguese expert in the European Normalization Committee for rendering and plastering mortars and in the EOTA Working Group for preparation of an Approval Guide for External Thermal insulation Composite Systems. She is also a member of the RILEM Committee for Repair Mortars for Historic Masonry (RHM). She collaborates in several Master Courses in Civil Engineering and Architecture Universities of Lisbon, Coimbra and Porto. Her research work is related with the performance of wall covering systems, durability and rehabilitation of wall coverings and conservation of historic mortars. Jorge de Brito graduated in Civil Engineering and received his Masters and Doctoral degrees at IST -Technical University of Lisbon, Portugal, where he is an associate professor. He is a member of IABSE, FIB, CIB and IABMAS, as well as of several reputed national engineering societies. He is a member of the following working groups: CIB W80 / RILEM 100-TSL -Service Life Prediction of Building Materials and Compo-Methodology for the rehabilitation of ancient gypsum plasterwork nents; CIB W86 -Building Pathology; CIB TG39 -Deconstruction; several national committees under CEN. His research work deals with deterioration, rehabilitation and management of concrete structures. He has coauthored the "Handbook of Concrete Bridge Management", published by ASCE Press in 2004.
Modified gypsum compounds: An ecological–economical choice to improve traditional plasters
Construction and Building Materials, 2012
h i g h l i g h t s " We studied hemihydrate-slag-pozzolanas pastes with improved performance than plasters. " The main hydration products are gypsum, ettringite and C-S-H. " Density is slightly higher than pure plasters but strength is almost triplicate. " Silica fume additions translate in excellent dimensional stability after 180 days.
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.
This thesis aims at contributing to promote the preservation of the Portuguese ancient gypsum-based plaster coatings. A literature review showed that there is little information about this heritage and no products in the market especially designed for its preservation. A systematic study of the composition of the interior plaster coatings belonging to several periods of the Portuguese history was conducted. More than 100 samples were collected from north to south of the country, representing different types of constructions (dwellings, palaces, churches, etc.) and epochs: Roman and Late Roman, Islamic, Low Middle-Age and Renaissance, Baroque and Post Baroque. A mineralogical survey was made, showing that the use of gypsum-based plasters in Portugal was significant only from the mid 1800’s to the first decades of the 20th century, mainly as wall and ceilings’ decorative programmes. A detailed mineralogical, physical and mechanical characterization was performed on the later period samples. Three main compositional patterns, directly related with the type of plastered elements and their application, were revealed: smooth surface, moulded on site and pre-moulded. Compatibility requirements for the restoration products were established, which, together with experimental application tests, allowed defining seven mixes. They were then submitted to physical and mechanical characterization tests and three mixes that best fulfilled the requirements established were selected.
Plasters : Gypsum or Calcite? A Preliminary Case Study of Syrian Plasters
Une série ďéchantillons d'enduits en provenance de sites des vallées de Balikh et de Khabour ont été soumis à analyse pour étude de leur composition. Les fragments ont été prélevés sur des éléments architecturaux divers (murs, fosses, sols, etc.) représentant des périodes différentes. L'analyse par diffractométrie montre que les échantillons en provenance de contextes néolithiques se composent principalement d'enduits, tandis que les échantillons datant de périodes ultérieures contiennent de la chaux, des enduits, ou un mélange des deux. Il est suggéré que cette differentiation peut s'expliquer par la proximité relative des matières premières aussi bien que par des considérations fonctionnelles.
Gypsum coatings in ancient buildings
Construction and Building Materials, 2007
Gypsum plasters from old buildings are a legacy of the building techniques of our ancestors. These coatings, frequently gifted with a high artistic value, are part of the historical building heritage of each country that needs to be well known and preserved.
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.
Production of Plaster from Gypsum Deposits in South Jordan: Improvement of the Setting Time
In this work, the improvement of the setting time (S.T.) of the Plaster of Paris produced from gypsum deposits of Jabal Mulaih, in Tafila, south Jordan, was investigated. The setting time of the reference sample was about 10 min and the final setting time reaches 20 min. Two approaches were investigated. The first one provided the application of some additives as potential retarders, while the second one required the control of the size of calcined gypsum materials produced in the crusher. Tens of samples were prepared and the setting time was measured by the Vicat methods, electrical conductance measurements, and temperature change. The morphology, bending breaking and burning resistance were studied, too. The influence of the water to plaster ratio, gypsum powder size, water tem - perature, water quality, admixtures, and aging time on the setting time was investigated. It was found that the setting time was delayed with increasing the water amount, the powder size, the admixture a...