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Talks and Poster Presentations (without Proceedings-Entry):

F. Hameed, B. Schillinger, A. Rohatsch, M. Zawisky, H. Rauch:
"Investigations of stone consolidants by neutron imaging";
Talk: 6th International Topical Meeting on Neutron Radiography, Kobe, Japan; 2008-09-14 - 2008-09-18.



English abstract:
The restoration of memorials and historical buildings is very challenging and expensive. One of the widely practiced methods of restoration is the use of stone consolidants. The chemical preservation of natural stones used in historical buildings is carried out by the use of stone strengthener agents. As these agents contain hydrogen, they offer good properties for neutron imaging. The main interest in the restoration process is the development of a suitable stone consolidant. In cooperation with the St. Stephans Cathedral and the geologists at Vienna University of Technology, we are investigating the penetration depth and distribution of different stone consolidants. These studies are being carried out with different stone samples, mostly porous natural building stones, limestones and sandstones. The two strengtheners used in this study are ethyl silicate and acrylic resin. Different techniques of neutron imaging have been used: Neutron radiography (NR), neutron tomography (NT) and time-resolved neutron imaging. Neutrons are particularly suitable to visualize water and conservation products inside porous materials like stones because of their strong attenuation by hydrogen. Neutron radiography and neutron tomography can be used successfully to visualize the distribution of consolidants both in two and three dimensions. Three dimensional investigations are necessary in order to discriminate surface effects from volume distribution of the consolidants. By comparison with conventional destructive techniques like SEM and optical microscopy non-destructive neutron imaging showed a clear advantage. It has been found that the distribution of the two consolidants investigated is completely different. Ethyl silicate is quite homogeneously distributed whereas the acrylic resind had a higher concentration on the outer surface. This suggested that the concentration of acrylic resin used was very high. Subsequently several experiments were performed with lower concentrations. Our results are very useful for geologists and conservators who can decide which consolidant and concentration is best suited.

Keywords:
Neutron imaging; building stones; consolidants; non-destructive testing

Created from the Publication Database of the Vienna University of Technology.