Kurt Heinrichs

Weathering damage on Pharaonic sandstone monuments in Luxor-Egypt

Abstract The Pharaonic stone monuments in Upper Egypt represent cultural heritage of outstanding universal value. All monuments have suffered weathering damage. In the year 2000 an Egyptian–German research co-operation was started aiming at the systematic investigation of stone weathering on the historical monuments in Upper Egypt as a contribution to monument preservation. Pilot studies were carried out on the Karnak Temple and on the Luxor Temple, composed of sandstones originating from the Gebel el-Silsila region. First results on the petrographical properties of these sandstones and their state of weathering damage on the Pharaonic temples in Luxor are presented.

Limestone weathering of historical monuments in Cairo, Egypt

Abstract Since pharaonic times local limestones have been used in Cairo for monument construction. Weathering damage on many historical stone monuments in Cairo is alarming. Studies on properties and weathering behaviour of the limestones were carried out by means of laboratory tests and in situ investigation of many historical monuments. The laboratory studies reveal considerable petrographical variations for the Middle Eocene limestones. The limestone weathering was assessed with respect to weathering forms, weathering products and weathering profiles. A classification scheme of weathering forms and their intensities was tailored to optimal applicability for all Cairo historical monuments constructed from limestones. Monument mapping has been applied for the detailed registration of weathering forms and as a basis for the quantitative rating of stone damage by means of damage categories and damage indices. For the historical monuments in the centre of Cairo the combined evaluation of weathering forms, weathering products and weathering profiles shows clear correlations between the development of weathering damage and salt loading of the limestones as a consequence of air pollution and rising humidity. They demonstrate the need and urgency for monument preservation measures.

Stone monuments of the Nemrud Dag sanctuary/Turkey – petrographical investigation and diagnosis of weathering damage [Steinmonumente des Nemrud Dag Heiligtums/Türkei – petrographische Untersuchung und Diagnose der Verwitterungsschäden]

The sanctuary of the Nemrud Dag in Eastern Turkey represents outstanding world cultural heritage. It was built by King Antiochos I of Commagene in the first century B.C. It is composed of a tumulus and three terraces. The west and east terrace are famous for their colossal limestone statues and sandstone stelae. These stone monuments have suffered weathering damage. The awareness of increasing damage and the danger of further irretrievable loss of cultural heritage have resulted in international efforts for sustainable monument preservation. Studies have been carried out, targeted to damage diagnosis as a fundamental contribution to appropriate monument preservation. The investigation has so far focused on the sandstone monuments and combines laboratory analysis of representative stone samples and in-situ investigation of the weathering damage by means of monument mapping and ultrasonic measurements. Field work was conducted in 1988 and 2002. Results are presented for the sandstone monuments regarding petrographical properties, state of weathering, rating of weathering damage and weathering progression. In addition, preliminary results are presented for the limestone monuments. The findings reveal a considerable petrographical range of the sandstones. The extent of damage on the sandstone monuments and weathering prognoses derived from evaluation of weathering damage indicate the need and urgency of monument preservation measures. Kurzfassung: Die Kultstätte des Nemrud Dag in der Osttürkei gehört zum Weltkulturerbe. Sie wurde von König Antiochos I. von Kommagene im ersten Jahrhundert vor Christus errichtet. Die Anlage besteht aus einem Tumulus (Grabhügel) und drei Terrassen. Auf der Westterrasse und der Ostterrasse befinden sich mächtige Kalksteinstatuen und Reliefstelen aus Sandstein. Diese Steinmonumente haben erhebliche Verwitterungsschäden erlitten. Die Zunahme der Schäden und die daraus erwachsende Gefahr weiteren Verlustes von kulturellem Erbe haben internationale Bemühungen um dauerhaft wirksame Erhaltungsmaßnahmen ausgelöst. An den Steinmonumenten wurden Untersuchungen zur Schadensdiagnose als Grundlage für die Planung und Durchführung geeigneter Schutzmaßnahmen durchgeführt. Die Untersuchungen konzentrierten sich bisher auf die Monumente aus Sandstein. Sie umfassten petrographische Laboruntersuchungen an repräsentativen Gesteinsproben sowie Vor-Ort-Untersuchungen der Verwitterungsschäden mit Hilfe der Bauwerkskartierung und Ultraschallmessungen. Geländekampagnen wurden in den Jahren 1988 und 2002 durchgeführt. Petrographische Eigenschaften, Verwitterungszustand, Schadensbewertung und Verwitterungsfortschritt werden für die Sandsteinmonumente ausführlich beschrieben und diskutiert. Zusätzlich werden erste Ergebnisse für die Kalksteinstatuen vorgestellt. Die Ergebnisse zeigen eine erhebliche petrographische Bandbreite der Sandsteine. Die Sandsteinmonumente sind insbesondere von Gesteinsverlust und Gesteinsablösungen unterschiedlicher Art und oft hoher Intensität betroffen. Schadensklassen und Schadensindizes haben sich als aussagekräftige Parameter für die Schadensbewertung erwiesen. Hohe Anteile starker bis sehr starker Schäden und hohe Schadensindizes weisen auf einen Besorgnis erregenden Zustand der meisten Sandsteinmonumente hin. Die Ergebnisse zur Verwitterungsprogression – abgeleitet aus den vergleichenden Studien in den Jahren 1988 und 2002 und Auswertungen von fotografischem Archivmaterial – lassen eine beachtliche Zunahme der Verwitterungsschäden innerhalb der letzten einhundert Jahre erkennen. Dies führt zu alarmierenden Schadensprognosen. Die Untersuchungsergebnisse verdeutlichen die Notwendigkeit und Dringlichkeit von Erhaltungsmaßnahmen. * Addresses of the authors: Dr. Kurt Heinrichs, Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstraße 4–20, D-52064 Aachen, Germany (heinrichs@lih.rwth-aachen.de); Dr. Bernd Fitzner, Geological Institute, RWTH Aachen University, Working group “Natural stones and weathering”, Wuellnerstraße 2, D-52062 Aachen, Germany (fitzner@geol.rwth-aachen.de). eschweizerbartxxx 520 Kurt Heinrichs & Bernd Fitzner 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

WEATHERING FORMS AND ROCK CHARACTERISTICS OF HISTORICAL MONUMENTS CARVED FROM BEDROCKS IN PETRA/JORDAN

Summary Weathering damage of varying intensity occurs at the monuments in the ancient town of Petra. These monuments are carved out of bedrock. As a result of fieldwork, the rocks were differentiated according to lithology. Furthermore, the weathering forms at the monuments were classified and mapped. From these results models of the development of weathering forms could be constructed. Additionally, microclimatic data were registered. Petrographie characteristic values relevant to weathering were determined through laboratory experiments on rock samples.

Kartierung und Bewertung von Verwitterungsschäden an Natursteinbauwerken

Kurzfassung: Weltweit werden grose Anstrengungen zur Erhaltung verwitterungsgeschadigter Natursteinbau- werke unternommen. Einhellig vertreten heute alle Bausachverstandigen die Meinung, dass der Weg vom gescha- digten zum dauerhaft und kostengunstig sanierten Bauwerk nur uber eine gesicherte Material- und Schadensdiag- nose fuhrt. Die Bauwerkskartierung ist ein zerstorungsfreies, zeit- und kostengunstiges Diagnoseverfahren, das vielfaltige Dokumentationsmoglichkeiten und eine quantitative Bewertung der Verwitterungsschaden an Natur- steinbauwerken erlaubt. Sie empfiehlt sich fur den routinemasigen Einsatz in der Denkmalpflege. Methode und Anwendungsbeispiele der Bauwerkskartierung werden vorgestellt. Abstract: Stone monuments represent an important part of our worlds cultural heritage. The awareness of in- creasing weathering damage on the monuments and the danger of irretrievable loss of cultural heritage have re- sulted in great efforts worldwide for sustainable monument preservation. A comprehensive damage diagnosis with precise characterization, interpretation and rating of stone damage is of vital importance for effective and eco- nomic monument preservation measures. The monument mapping method is presented as an experienced non- destructive procedure for in situ investigation and evaluation of stone damage. It can be applied to all stone types and to all kind of stone monuments. The evaluation of weathering damage is based on lithological mapping and mapping of weathering forms. Weathering forms represent the visible results of weathering processes which are initiated and controlled by interacting weathering factors. A detailed classification scheme of weathering forms has been developed for objective and reproducible mapping. The results of monument mapping ensure the precise documentation and quantitative evaluation of weathering damage in dependence on stone types, environmental conditions and monument exposure characteristics. They provide information on weathering factors and processes, and they allow characterization and quantification of weathering progression including weathering prognosis. Damage categories and damage indices have been established for the rating of damage. They are very suitable in- dicators of need and urgency of preservation measures. The monument mapping method can also be recommended for the control of preservation measures and for reevaluation of weathering damage in the framework of long-term monitoring and maintenance of monuments. Schlusselworte: Natursteinbauwerke, Verwitterungsschaden, Schadensdiagnose, Bauwerkskartierung, Verwitte- rungsformen, Verwitterungsfortschritt, Schadensbewertung, Schadensklassen, Schadensindizes

Quantitative Analysis of Salt Crystallization–Dissolution Processes on Rock-Cut Monuments in Petra/Jordan

Salt weathering represents a major cause of damage on stone monuments worldwide. However, processes of salt weathering still cannot be explained satisfactorily. Further systematic investigation of stone monuments is required for the improvement of knowledge on active salt weathering processes and controlling factors. Assessment of the dynamics of salt crystallization–dissolution processes is a focus of modern salt weathering research. The overall aim of the ‘petraSalt’ research project are real-time/real-scale weathering models that depict characteristic interdependencies between stone properties, monument exposure regimes, environmental influences, salt loading, salt crystallization–dissolution behaviour and salt weathering damage. The rock-cut monuments of ancient Petra in Jordan were selected for studies. A main part of the project is the joint evaluation of salt load and environmental conditions acting on it, allowing a differentiated, depth-dependent quantification of the complex salt crystallization–dissolution processes, considering diurnal and seasonal variation. The approach is exemplified.