21-41

Articles

• Bala’awi, Fadi
• Alshawabkeh, Yahya
• Alawneh, Firas
• al Masri, Eyed

The treasury is the icon monument of the world heritage site of ancient Petra city. Unfortunately, this important part of the world’s cultural heritage is gradually being diminished due to weathering and erosion problems. This give rise to the need to have a comprehensive study and full documentation of the monument in order to evaluate its status. In this research a comprehensive approach utilizing 2D-3D documentation of the structure using laser scanner and photogrammetry is carried parallel with a laboratory analysis and a correlation study of the salt content and the surface weathering forms. In addition, the research extends to evaluate a set of chemical and physical properties of the case study monument. Studies of stone texture and spatial distribution of soluble salts were carried out at the monument in order to explain the mechanism of the weathering problem. Then a series of field work investigations and laboratory work were undertaken to study the effect of relative humidity, temperature, and wind are the main factors in the salt damage process. The 3D modelling provides accurate geometric and radiometric properties of the damage shape. In order to support the visual quality of 3D surface details and cracks, a hybrid approach combining data from the laser scanner and the digital imagery was developed. Based on the findings, salt damage appears to be one of the main problems at this monument. Although, the total soluble salt content are quite low, but the salts contamination is all over the tested samples in all seasons, with higher concentrations at deep intervals. The thermodynamic calculations carried out by this research have also shown that salt damage could be minimised by controlling the surrounding relative humidity conditions. This measure is undoubtedly the most challenging of all, and its application, if deemed feasible, should be carried out in parallel with other conservation measures.

• History and Archaeology
• Physical sciences

• Αρχαιολογία

Petra, Physical and Mechanical Properties, Decay, 2D-3D documentation, Salt, Environmental, Monitoring Programs, Thermodynamic

Corresponding author: fadi.balaawi@hu.edu.jo

1. Alshawabkeh, Y. and Haala, N., and Dieter Fritsch, (2010) A New True Ortho-Photo Methodology for Complex Archaeological Application, Archaeometry, Volume 52, Issue 3, 517–530.Alshawabkeh, Y. & Haala N. (2005) Automatic Multi-Image Photo Texturing of Complex 3D Scenes. CIPA IAPRS Vol. 34-5/C34, 68-72.Arnold, A. and Zehnder, K., (1991) Monitoring wall paintings affected by soluble salts. In Cather, S., (ed.), 1991. the conservation of Wall Paintings. Proceedings of a Symposium organized by the Courtauld Institute of Art, University of London, and the Getty Conservation Institute, London. July 13-16, 1987. Los Angeles: Getty Conservation Institute, 103-135.Arnold, A. and Zehnder, K., (1990) Salt weathering on monuments. In Zezza, F., (ed.), (1990). 1st International symposium on the Conservation of Monuments in the Mediterranean Basin. Bresica: Garfo Publication, 31-38.Bala’awi, F., (2002) Conservation Work at Petra: A Critical review. Unpublished MA Dissertation. London: University College London, 105 p.Canny, J. (1986) A Computational Approach to Edge Detection, Ieee transactions on Pattern Analysis and Machine Intelligence, Vol. 8, No. 6, Nov.Clegg, S, L., (1993) PItZ93: a FORTRAN program for determining activity in electrolyte solutions available from S. L. Clegg or P. Brimblecombe at the School of Environmental Sciences of the University of East Anglia, Norwich, UK.Clegg, S, L. and Whitefield, M., (1991). Activity coefficient in natural waters. In Pitzer, K.S., (ed.), 1991. In Activity Coefficient in electrolyte solutions. Baca Raton: CRC Press, 279-434.Correns, C., (1949) Growth and dissolution of crystal under liner pressure. Discussion of the Faraday society. Vol. 5, 267-271.Doehne, E., (1994) In situ dynamic of sodium sulfate hydration and dehydration in stone pores: observation of high magnification using the environmental scanning electron microscope. In Fassina, V. and Zezza, F., (eds.), 1994. 3rd International symposium on the Conservation of Monuments in the Mediterranean Base, 143-150.Fitzner, B. and Heinrichs, K., (2002) Damage diagnosis on stone monuments -weathering forms, damage categories and damage indices. In Přikryl, R. and Viles, H., (eds.), 2002. understanding and Managing stone Decay: Proceeding of the International Conference stone Weathering and Atmospheric Pollution Network (sWAPNet 2001). Prague: Charles University and the Karolinum Press, 11-56.Fitzner, B., Heinrichs, K. and Kownataki, R., (1995) Weathering forms - classification and mapping. In Denkmalpflege und Naturwissenschaft, Natursteinkonservierung. I. Berlin: Ernst and Sohn, 41-88.Flatt, R., (2002) Hydration pressure: A bad case of crystallization pressure. SALteXPert salt Damage and Desalination - A Combined short Course/Workshop organized by the Getty Conservation Institute and ACrCCHIP, 2002, Prague- Czech Republic. (16p).Goudie, A. and Viles, H., (1997). salt Weathering Hazards. Chichester John Wiley & Sons Ltd. 241p.Khouri, R., (1986). Petra: A Guide to the Capital of Nabateans. London: Longman Publication. 160p.Kühlenthal, M. and Fisher, H., (eds.), (2000). Petra: the restoration of the rock Cut tomb Façades. Müchen: Bayerisches Landesamt für Denkmalpfleg Publication.Heinrichs, K., (2008). Diagnosis of Weathering Damage on Rock-Cut Monuments in Petra, Jordan. environmental Geology, 56(3), 643–75.Heinrichs, K. and Fitzner, B., (2000). Lithotypes of rock-carved monuments in Petra/ Jordan - classification and petrographical properties. ADAJ (Annual of the Department of Antiquities, Amman - Jordan). Vol. 44, 283-312.Heinrichs, K. and Fitzner, B., (1999). Comprehensive characterization and rating of the weathering state of the rock carved monuments in Petra/Jordan - weathering forms, damage categories and damage index. ADAJ (Annual of the Department of Antiquities, Amman - Jordan). Vol. 43, 321-351.ICOMOS, (1931), the Athens Charter for the restoration of Historic Monuments. Adopted at the First International Congress of Architects and Technicians of Historic Monuments, Athens, ICOMOS Publication. [On Line]. Available from:www.icomos.org/docs/athens_ charter.htm {Accessed on 15 October 2001}.Jasper, D. and Barjous, M., (1992). Geotechnical studies and geological mapping of ancient Petra city. town Mapping Project, Bulletin 1. Amman: Hashemite Kingdom of Jordan - Ministry of Energy and Mineral Resources - Natural Resources Authority - Geological Directorate - Geological Mapping Division. (60p).Nicholson, D., (2001). Pore properties as indicators of breakdown mechanisms in experimentally weathered limestone. earth surface Processes and Landforms. Vol. 26, 819-838.Palmer, P., Dabis, H. & Kittler, J. (1996). A performance measure for boundary detection algorithms. CVGIP: Image Understanding, 63(3), 476-494.Pender, R., (2000). the Behaviour of Moisture in the Porous support Materials of Wall Paintings: An Investigation of Some Environmental Parameters. Unpublished PhD Thesis, London: Courtauld Institute of Art, University of London. (328p).Pflüger, F., (1995). Archaeo-Geology in Petra Jordan. ADAJ (Annual of the Department of Antiquities, Amman - Jordan). Vol. 29, 281-295.Price, C.A., (ed.) (2000). An expert Chemical Model for Determining the environmental Conditions Needed to Prevent salt Damage in Porous Materials. European Commission Report 11, Protection and Conservation of European Cultural Heritage. London: Archetype Publications. (136p).Price, C.A. and Brimblecombe, P., (1994). Preventing salt damage in porous materials. In Roy, A. and Smith, P., (eds.), (1994). Preventive Conservation, Practice, theory and research. London: International Institute for Conservation of Historic and Artistic Works, 90-93.Rodriguez-Navarro, C. and Doehne, E., (1999a). Origins of honeycomb weathering: The role of salts and wind. Geological society of America Bulletin. Vol. 111, 1250-1255.Rodriguez-Navarro, C. and Doehne, E., (1999b). Salt weathering: influence of evaporation rate, supersaturation and crystallization pressure. earth surface Processes and Landforms. Vol. 24, 191-209.Rossi-Manaresi, R. and Tucci, A., (1991). Pore structure and the disruptive or cementing effect of salt crystallization in various types of stone. studies in Conservation. Vol. 36, 53-58.Sawdy, A., (2001). the Kinetics of salt Weathering of Porous Materials: stone Monuments and Wall Paintings. Unpublished PhD Thesis, University College London. (325p).Scherer, G., (2000). Stress from crystallization of salt in pores. In Fassina, V., (ed.), (2000). 9th International Congress on Deterioration and Conservation of stone. Venice June 19-24, 2000. Amsterdam: Elsevier, 187-194.Scherer, G., (1999). Crystallization in pores. Cement and Concrete research, Vol. 29. pp.: (1347-1358).Steiger, M. and Dannecker, W., (1995). Hygroskopishe eigenschaften und kristallisationsverhalten von salzgemischen. In Snethlage, R., (ed.), (1995). Jahresberichte Steinzerfall: Servierung 1993. Berlin: Ernst & Sohn Publication. pp.: (115-128).Steiger, M. and Zeunert, A., (1996). Crystallization properties of salt mixtures: comparison of experimental results and model calculation. In Riederer, J., (ed.), 1996. Proceedings of the 8th International Congress on the Deterioration and Conservation of stone. Berlin, 30 September - 4 October 1996. Berlin: Möller druck und verlag gmbh, 535-544.Ulama, M., (1997), All Petra: A Wonderland of the Past, Amman- Jordan: Al- Ulama Publishing Centre.Viles, H., et al. (1997). Group report. What is the state of our knowledge of the mechanisms of deterioration and how good are estimates of rates of deterioration? In Baer, N. and Snethlage, R., (eds.), (1997). saving our Architectural Heritage-the Conservation of Historic stone structure. Report of the Dahlem Workshop. Berlin, 3-8 March 1996: John Wiley & Sons Ltd, 95-112.Winkler, E., (1994). stone in Architecture: Properties, Durability. Third Edition. Berlin: Springer-Verlag Publications. (313p).Winkler, E. and Singer, P., (1972). Crystallization pressure of salts in stone and concrete. Geological society of America Bulletin. Vol. 83. pp.: (3509-3514).Zayadine, F., (1992). Petra and the Caravan Cities, Department of Antiquities Publications, Amman Jordan.