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Evidence of amorphous Ca-phosphate precipitate caused by bio mineralisation in 4-5th CE lime plasters of the previously submerged east coastal monument of Salvankuppam

Singh Manager R., Kumar S. Vinodh, Ganaraj Kuntikana

Mineralogia

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2021

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Vol. 52, iss. 1

19--30

EN

The lime plasters of the excavated monument of Salvankuppam, previously submerged and exposed by the Tsunami occurred in the Indian Ocean on 26th December 2004 was studied with different analytical techniques. The temple is dated 4-5th century CE. The XRF, XRD, FTIR, NMR, SEM-EDX analysis of the lime plasters evidenced particular occurrence of phosphatised bacterial remains in saline conditions. The formation of amorphous Ca-phosphate by bio mineralization was identified in the plasters by the analyses. The plasters are made of air-lime with coarse aggregates and seashells inclusion as confirmed by the thermal and chemical analysis. The microstructure and morphological investigations of mineralized microbial structures by SEM-EDX indicated the formation of amorphous Ca-phosphate. The unordered and fibrous spherulites have hardened and reduced porosity of the plaster by bio mineralization as observed through MIP analysis. The 16S rRNA sequencing has identified the Pseudomonas strains mainly responsible for the clustering of amorphous Ca-phosphate particles around the bacterial colony.

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Metody badań zapraw historycznych – problematyka konserwatorska

Klimek B.

Budownictwo i Architektura

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2015

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Vol. 14, nr 2

63--69

PL

Historyczne zaprawy są cennym źródłem informacji o technikach budowlanych stosowanych w przeszłości. Są one interesujące dla architektów, technologów i archeologów, którzy wykorzystują zaprawy jako dodatkowe kryterium dla ustalenia chronologii budowy muru w zabytkowych budynkach. Zgodnie z celem badań, stosowane są określone metody analityczne w zależności od wybranego programu badań i prac. Podstawowym problemem jest niewielki zasób opracowanych materiałów mogących służyć do porównań, drugi problem wynika z braku właściwej oceny materiałów stosowanych do napraw i konserwacji w przeszłości. Obecnie w praktyce dla prowadzonych prac badawczych przyjęte i mierzone parametry określane są indywidualnie dla obiektu, lub wynikają ze specyfiki badań prowadzonych przez architektów, archeologów, konserwatorów. Niestety przy braku określonego schematu postępowania uzyskanych wyników nie można porównać

EN

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. Plaster used in former time are a valuable source of information of building techniques used in the past. They are of interest to technologists and archaeologists, who use plasters as an additional criterion for establishing the chronology of the construction of walling in historic buildings. In accordance with the purpose of the investigations, appropriate analytical methods of a defined precision and specially chosen program are applied. 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. The necessity has been emphasized for the introduction of investigation standards to be universally binding, which would make it possible to compare the results of investigations carried out in different laboratories. The practice has been for analytical programs adopted and parameters measured to be individually chosen by the particular investigators and cannot be compare.

3

Investigation of lime mortars and plasters from archaeological excavations in Hippos (Israel) using Electron Paramagnetic Resonance

Kabacińska Z., Krzyminiewski R., Michalska D., Dobosz B.

Geochronometria

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2014

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Vol. 41, no. 2

112--120

EN

This study presents the preliminary results of investigation of the lime mortars and plasters from archaeological excavations in Hippos (Israel), using Electron Paramagnetic Resonance (EPR) spectroscopy. The research was conducted in order to characterize the building material and its reaction to ionizing radiation. The ancient settlement Hippos, situated on the east shore of the Sea of Galilee, functioned from the 3rd cent. BC until it was destroyed by the earthquake in 749 AD. Lime mortars and plasters show carbonate and locally gypsum character of binder and different kind of aggregate. Samples were γ-irradiated and measured using X-band EPR spectrometer. Computer Resolution Enhancement Method was applied to the complex spectra. Some of the γ-induced EPR signals were attributed to CO 2 and CO 3 3- paramagnetic centres. Exponential growth of the dose response curve above 1 kGy and saturation for doses above 20 kGy was observed. For doses lower than 1 kGy the dose response curve has a linear character. The presence of γ-sensitive carbonate paramagnetic centres could indicate that, after further studies, well-chosen samples of mortars and plasters might be suitable for EPR dating, assuming the centres have been sufficiently bleached during the manufacturing process.