ABSTRACT: 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.

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ABSTRACT: Most monuments and buildings in the Maltese Islands are constructed of the local Globigerina Limestone. Today, this Globigerina Limestone shows considerable damage in many buildings, particularly through alveolar weathering, which is frequently very intense. Owing to Malta’s marine environment, salt crystallization in the stone's pore spaces has been recognizedasthemainweatheringprocessresponsibleforthedeteriorationofthecountry's monuments. In order to obtain more information on the fabric-dependent weathering processes of Globigerina Limestone, detailed analyses were carried out. Globigerina Limestone samples obtained from stone types with two different known qualities were characterized according to petrographical, geochemical and physical properties. These included porosity, pore radii distribution and tensile strength, as well as water and humidity transport properties. Investigations by means of salt crystallization tests on quarry samples of both stone types reinforced the idea that the extent of salt weathering depends on salt type and concentration and pore-space properties. Visible weathering damage was recorded and evaluated for a representative monument (the Church of Santa Marija Ta' Cwerra in Siggiewi) by means of a monument mapping method, which was carried out twice over a period of 9 years (1995 and 2004). The identified weathering forms were also correlated with a previously developed weathering model for Globigerina Limestone. According to the results of the mapping, salt analyses carried out on samples from the church and salt-loading tests on quarry samples, there exists a significant correlation between visible damage and salt load. The zoning of weathering damage is obviously related to different salt concentrations. The zone with severe weathering damage is characterized by a high concentration of halite. Consequently, salt weathering represents the main damage process for the Globigerina Limestone of Malta.

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ABSTRACT: Stone monuments represent an important part of our world's cultural heritage. The awareness of increasing stone damage has resulted in great efforts worldwide for sustainable monument preservation. A precise damage diagnosis with comprehensive characterization, interpretation and rating of stone damage is required as the basis for effective and economic monument preservation measures. The experienced methodological approach to the assessment of stone damage combines in situ investigation and laboratory studies. Modern investigation methods are presented in this book. Their application is demonstrated by international case studies.
The book is addressed to organizations and monument authorities involved in planning and decision making of monument preservation policies and strategies as well as to restorers, conservators, architects, scientists, engineers, consultants, project managers and companies involved in damage diagnosis and monument preservation activities.

TABLE OF CONTENTS:

KURZFASSUNG: Weltweit werden große Anstrengungen zur Erhaltung verwitterungsgeschädigter Natursteinbauwerke unternommen. Einhellig vertreten heute alle Bausachverständigen die Meinung, dass der Weg vom geschädigten zum dauerhaft und kostengünstig sanierten Bauwerk nur über eine gesicherte Material- und Schadensdiagnose führt. Die Bauwerkskartierung ist ein zerstörungsfreies, zeit- und kostengünstiges Diagnoseverfahren, das vielfältige Dokumentationsmöglichkeiten und eine quantitative Bewertung der Verwitterungsschäden an Natursteinbauwerken erlaubt. Sie empfiehlt sich für den routinemäßigen Einsatz in der Denkmalpflege. Methode und Anwendungsbeispiele der Bauwerkskartierung werden vorgestellt.

ABSTRACT: Stone monuments represent an important part of our world´s cultural heritage. The awareness of increasing weathering damage on the monuments and the danger of irretrievable loss of cultural heritage have resulted 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 economic 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 indicators 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.

SCHLÜSSELWORTE: Natursteinbauwerke, Verwitterungsschäden, Schadensdiagnose, Bauwerkskartierung, Verwitterungsformen, Verwitterungsfortschritt, Schadensbewertung, Schadensklassen, Schadensindizes.

KEYWORDS: stone monuments, weathering damage, damage diagnosis, monument mapping, weathering forms, weathering progression, rating of damage, damage categories, damage indices.

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ABSTRACT: Stone monuments represent an important part of our world´s cultural heritage. The awareness of increasing stone damage on monuments and the danger of irretrievable loss of cultural heritage have resulted in great efforts worldwide for sustainable monument preservation. A precise damage diagnosis with the comprehensive characterization, interpretation and rating of stone damage represents the basis for effective and economic monument preservation measures. The experienced methodological approach to the assessment of stone damage combines in situ investigation and laboratory studies. The monument mapping method is presented as an established non-destructive procedure for in situ studies on stone damage. It can be applied to all stone types and to all kinds of stone monuments. The use of weathering forms, damage categories and damage indices for the registration, documentation, quantitative evaluation and rating of stone damage is explained. Furthermore, complementary in situ measurements are discussed. A wide range of analytical procedures and weathering simulation tests contribute to modern damage diagnosis on stone monuments.

ABSTRACT: Stone monuments represent an important part of the world´s cultural heritage. All stone monuments are affected by weathering. The increasing stone damage on monuments and the danger of irretrievable loss of cultural heritage has resulted in great efforts for sustainable monument preservation. According to international directives and conventions, a comprehensive diagnosis is of vital importance for the understanding of weathering damage on stone monuments, and it represents the basis for effective and economic monument preservation measures.
The quantification and rating of weathering damage is a very important objective of diagnosis. The in-situ investigation of stone monuments means an important part of the methodological approach. The monument mapping method has been established as a non-destructive procedure for the registration, documentation and evaluation of weathering phenomena. It can be applied to all stone types and to all kinds of stone monuments. Maps and quantitative evaluation address type, intensity and distribution of the weathering phenomena, and in addition their dependencies on stone types and monument characteristics. They facilitate the deduction of quantitative information on weathering progression, which allows weathering prognosis. Damage categories and damage indices have been introduced for the rating of the weathering phenomena. They are used as indicators of the need and urgency of preservation measures.
In-situ measurements (e.g. ultrasonic measurements, drilling resistance measurements, rebound hardness measurements) are applied for additional quantitative information on weathering damage, including the detection of non-visible stone damage. The change of stone properties - comparing the unweathered and weathered stone - is considered for the quantification and rating of damage.
The combination of suitable measuring procedures and phenomenological methods such as monument mapping ensures the consistent assessment of stone damage from the microscale (mm to cm) to the macroscale (entire monuments or stone structures).
Reliable quantitative information on weathering damage is essential for the decision and implementation of proper intervention for the protection of stone monuments. It enhances the objective and reproducible long-term monitoring of a monument, the quality control of preservation measures and the maintenance of the monument.

KEYWORDS: stone monuments, weathering damage, damage diagnosis, monument mapping, in-situ measurements.

© 32nd International Geological Congress

ABSTRACT: Comprehensive documentation is of vital importance in the field of stone monument preservation. The approach to the protection of stone monuments can be subdivided into anamnesis, diagnosis and therapy. According to established international directives, documentation is a necessary part of all three worksteps.
The particular objectives and items of documentation within the scope of anamnesis, diagnosis and therapy are presented. Evaluation and graphic documentation of stone deterioration is presented by means of examples referring to in-situ investigation of stone monuments in the framework of diagnosis.

KEYWORDS: documentation, anamnesis, diagnosis, therapy, monument preservation.

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ABSTRACT: The prehistoric Bangudae Petroglyph in the Ulsan area represents an outstanding National Treasure of the Republic of Korea. Since the construction of the Sayeon dam, the petroglyph with about two hundred carvings is periodically submerged by the Sayeon reservoir. The danger of increasing damage has resulted in intensive efforts to protect this cultural heritage. Diagnosis and risk prognosis studies were carried out. Results of petrographical studies, monument mapping and in situ measurements are presented. Types, degree and zonation of damage are evaluated. The risk estimation derived from the studies confirms the necessity of preservation measures.

KEYWORDS: Petroglyph - Rock weathering - Damage diagnosis - Risk estimation - Republic of Korea - Ulsan Metropolitan City - Daegok-Ri.

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ABSTRACT: The rock-cut monuments in Petra / Jordan represent outstanding world cultural heritage. The monuments are threatened by weathering damage. Studies were carried out in order of a comprehensive damage diagnosis and the contribution to sustainable monument preservation. The assessment of weathering progression means an important part of damage diagnosis. Weathering forms provide essential information on weathering progression. Based on a classification scheme of weathering forms, many representative monuments were studied by means of monument mapping with respect to type, intensity and distribution of weathering forms. The quantitative evaluation of the weathering forms allowed to calculate average weathering rates and to deduce sequences of weathering forms. Weathering progression factors were introduced as basis for the determination of weathering progression curves which quantify realistically the recession of the stone surface in dependence upon time. The methodological approach to the characterization, quantification and prognosis of weathering progression is explained and results are presented for two lithotypes.

ABSTRACT: The famous monuments of the ancient city of Petra in Jordan represent outstanding world cultural heritage. More than 800 monuments were carved by the Nabataeans from Cambrian and Ordovician sedimentary bedrocks about 2000 years ago. In 1985 the UNESCO inscribed Petra on the World Heritage List. The rock-cut monuments are threatened by weathering damage. In 1998, 2000 and 2002 the World Monument Fund (WMF) inscribed Petra on the list of the one hundred most endangered monument assemblies of the world.
Studies were carried out for comprehensive damage diagnosis and contribution to sustainable monument preservation. The studies combined in-situ investigation and laboratory analysis. The survey of lithotypes and the analysis of their petrographical properties resulted in a new lithostratigraphic classification including sixteen main lithotypes and nine sublithotypes with considerable differences in their properties. A detailed classification scheme of weathering forms - representing the phenomenological results of the weathering processes - was established for the Petra monuments as basis for the precise and reproducible registration, documentation and evaluation of all apparent weathering forms according to type and intensity. Results of monument mapping - lithological mapping and mapping of weathering forms - provided the basis for a new approach to the assessment of weathering progression on the monuments.
The systematic characterization and quantitative evaluation of successions of weathering forms - considering all characteristical types and intensities regarding loss of stone material, deposits on the stone surface and current detachment of stone material - and the calculation of weathering rates and weathering progression factors were jointly used for the quantification of weathering progression on the rock-cut monuments in dependence upon lithotypes. The weathering progression curves obtained for the most important lithotypes show a continuous acceleration of weathering progression, approximating a linear weathering progression only in very advanced phases of weathering. The extrapolation of the results allowed quantitative weathering prognoses for the Petra monuments for the first time. The results contribute essentially to the thorough understanding of weathering damage on the Petra monuments. They enhance risk estimation and they represent an important basis for risk management.

KEYWORDS: damage diagnosis, monument mapping, weathering progression, weathering prognosis.

© 32nd International Geological Congress

ABSTRACT: More than six hundred Islamic monuments are concentrated in the centre of Cairo / Egypt. In 1979 Islamic Cairo was inscribed by UNESCO on the World Heritage List. Tertiary porous limestones from local quarries were used for the construction of the monuments. Many of the Islamic monuments in Cairo are threatened by damage due to stone weathering.
Studies on properties and weathering behaviour of the limestones were carried out for damage diagnosis. The laboratory analyses revealed a wide range of limestone varieties with considerable differences in their properties. The limestone weathering was assessed with respect to weathering forms, weathering products and weathering profiles, which in combination characterize the weathering state. The monument mapping method was applied for the detailed registration, documentation and quantitative evaluation of weathering forms and as the basis for the rating of stone damage by means of damage categories and damage indices. In-situ measurements such as rebound hardness measurements and drilling resistance measurements were carried out for complementary information on the weathering state of the limestones.
A great variety of weathering forms was found on the Islamic monuments, characterizing loss of stone material, deposits on the stone surface, current detachment of stone material and structural discontinuities. Results for lower parts of the monuments showed that all kinds of stone detachment and subsequent loss of stone material are linked to salt loading of the limestones. The significance of salts (halite, gypsum) became obvious in all results on weathering forms, weathering products and weathering profiles. The weathering profiles provided important information on the development of stone damage on the limestone monuments. A clear correlation could be stated between extent of salt loading and degree of damage, which revealed salt weathering as a significant process harming the Islamic monuments in Cairo. Natural contents of salts in the limestones, but especially salt formation as the result of air pollution and rising damp causes the salt loading of the limestones.
The results indicate the need of preservation measures - remedial and preventive measures. Control of capillary rise, desalination, cleaning, stone repair, fixation or consolidation of loose stone material, surface protection, structural reinforcement, stone replacement and environmental management are in discussion.

KEYWORDS: Limestone monuments, weathering damage, damage diagnosis, salt weathering, monument preservation.

© 32nd International Geological Congress

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.

KEYWORDS: Pharaonic monuments, Karnak Temple, Gebel el-Silsila sandstones, Weathering forms, Monument mapping, Damage index.

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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 for the Middle Eocene limestones considerable petrographical variations. 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 exhibit the need and urgency of monument preservation measures.

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ABSTRACT: Mineralogical-petrographical studies along with mineral mapping of the building facades made or decorated with natural stone and of the art monuments in St. Petersburg are the necessary parts of the restoration works. These studies are as well means of the monitoring of the natural stone´s state condition in urban environment.

ABSTRACT: Stone monuments represent an important part of our world´s cultural heritage. The alarming increase of weathering damage on natural stone monuments and the danger of irretrievable loss of cultural heritage have resulted in great efforts worldwide for sustainable monument preservation. Knowledge of the properties and the weathering behaviour of the natural stones is required, as well as knowledge of the weathering factors and weathering processes which initiate and control the weathering behaviour. The precise damage diagnosis with comprehensive characterization, interpretation and rating of stone damage in dependence on stone properties, environmental conditions, monument characteristics and time represents an important basis for effective and economic monument preservation measures.
The experienced methodological approach to meaningful damage diagnosis on stone monuments applied by the Aachen working group "Natural stones and weathering" at numerous stone monuments worldwide combines the complementary diagnostical steps of in-situ investigation, laboratory analysis and weathering simulation. With respect to in-situ investigation, monument mapping and measurements are presented. The monument mapping method has been developed as a non-destructive procedure for the exact registration, documentation and evaluation of weathering phenomena. Monument mapping still represents the only method, which allows to describe and evaluate entire stone surfaces precisely and reproducibly according to stone types and apparent type, intensity and distribution of weathering phenomena. The consequent use of weathering forms, damage categories and damage indices for registration, documentation, quantitative evaluation and rating of stone damage and as basis for planning, execution, certification and control of monument preservation measures, long-term survey and maintenance of stone monuments is explained. Examples of suitable in-situ measurements are shown, which provide important complementary quantitative information on stone materials and their weathering characteristics.
The long and complex geological history has resulted in a great variety of natural stones with remarkable variation of their properties. Modern laboratory procedures for the analysis of stone properties and their modifications due to weathering are presented. Emphasize is given to the analysis of porosity characteristics, which decisively condition the durability and the weathering behaviour of natural stones. Finally, weathering simulation tests are presented as tools for the elucidation of weathering mechanisms and processes, the quantification of weathering progression, the appraisal of stone quality and the rating of the effectiveness of stone treatment.
Practical applications of the different diagnostical steps are demonstrated by means of case studies carried out in the frame of international research projects.

ABSTRACT: Stone monuments represent an important part of our world´s cultural heritage. The awareness of increasing stone damage on monuments coupled with the danger of irretrievable loss of cultural heritage has resulted in great efforts worldwide for monument preservation.
Meaningful damage diagnosis is required for comprehensive characterization, interpretation and rating of stone damage. In situ investigation of monuments makes an important contribution to damage diagnosis on stone monuments. The monument mapping method is presented as an established non-destructive procedure for in situ studies on stone damage. It can be applied objectively and reproducibly to all stone types and to all kinds of stone monuments. The consequent use of weathering forms, damage categories and damage indices for precise registration, documentation, quantitative evaluation and rating of stone damage is explained.
Furthermore, in situ measurements and well-directed sampling are discussed. Additionally, a wide range of analytical procedures in the laboratory and different types of weathering simulation tests contribute to modern damage diagnosis on stone monuments.

KEYWORDS: Natural stones, stone monuments, damage diagnosis, in situ investigation, monument mapping, weathering forms, rating of stone damage, damage categories, damage indices, in situ measurements, sampling, laboratory analysis, stone properties, weathering simulation.

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ABSTRACT: Stone monuments represent an important part of our world´s cultural heritage. The awareness of increasing stone damage on monuments coupled with the danger of irretrievable loss of cultural heritage has resulted in great efforts worldwide for monument preservation. Meaningful damage diagnosis is required for comprehensive characterization, interpretation and rating of the stone damage. In situ investigation of monuments makes an important contribution to damage diagnosis on stone monuments. The monument mapping method is presented as an established non-destructive procedure for in situ studies on stone damage. It can be applied objectively and reproducibly to all stone types and to all kinds of stone monuments. The consequent use of weathering forms, damage categories and damage indices for precise registration, documentation, quantitative evaluation and rating of stone damages is explained. It provides a modern contribution to improvement of scientific knowledge in the field of stone deterioration and it facilitates important information on the need, urgency and appropriate types of economic and sustainable monument preservation measures. Furthermore, it is very suitable for certification and control of preservation measures and for long-term survey and maintenance of stone monuments. The innovative evaluation strategy ‘weathering forms – damage categories – damage indices’ is based on a detailed classification scheme of weathering forms, that has been developed on the basis of investigation at numerous monuments worldwide considering different stone types and different environments. The methodological approach to systematic evaluation of stone damage -based on monument mapping - is described and practical applications are demonstrated by means of some case studies.

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ABSTRACT: Precise diagnosis is required for characterisation, interpretation, rating and prediction of the weathering damages at stone monuments and is vital for remedy of stone damages and sustainable monument preservation. Quantitative rating of damages represents an important scientific contribution to reliable damage diagnosis at stone monuments. Damage indices are introduced as new tool for scientific quantification and rating of stone damages. Application of damage indices improves stone damage diagnosis and is very suitable for evaluation and certification of preservation measures and for long-term survey and maintenance of stone monuments. Importance and use of damage indices are presented for monuments in Germany, Malta, Jordan, Egypt and Brazil.

RESUMEN: La caracterización, interpretación, valoración y predicción de los daños de alteración en monumentos de piedra requieren un diagnóstico preciso de los mismos. Este tipo de diagnóstico es fundamental para remediar los daños en la piedra y para una conservación adecuada de los monumentos. La valoración cuantitativa de los daños representa una contribución científica importante para un diagnóstico de alteración adecuado en monumentos pétreos. Los índices de daños se introducen como una nueva herramienta para la cuantificación y valoración científica de los daños en piedra. El uso de los índices de daños supone un paso hacia adelante en el diagnóstico de alteración de la piedra y es muy adecuado para la evaluación y control de las medidas de conservación, así como para estudios a largo plazo y el mantenimiento de monumentos hechos en piedra. La importancia y el uso de índices de daños se presentan para diferentes monumentos en Alemania, Malta, Jordania, Egipto y Brasil.

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Stone monuments represent an important part of our world cultural heritage. All stone monuments are affected by weathering. At many monuments weathering damages are alarming. Precise damage diagnosis is required for characterization, interpretation and rating of weathering damages and for sustainable monument preservation. Quantification and prediction of weathering damages have become important concerns of modern scientific approach. In situ investigation of monuments means an essential contribution to damage diagnosis. The monument mapping has been established as a non-destructive procedure for precise registration, documentation and evaluation of weathering damages. The mapping method can be applied to all stone types and to all kinds of stone monuments ranging from sculptures to facades or entire monuments. The method meets great international acceptance. Evaluation and quantification of weathering damages by means of monument mapping is based on systematic investigation on weathering forms.
Weathering forms represent the visible result of weathering processes which are initiated and controlled by weathering factors. By means of monument mapping, all weathering forms are registered systematically according to type, intensity and distribution. A detailed classification scheme of weathering forms has been developed in order to guarantee objective and reproducible registration. Computer programmes have been tailored to optimal processing, illustration and quantitative evaluation of mapping information. Illustration and quantitative evaluation of weathering forms ensure information on

• characteristical spectrum of weathering forms,
• interrelations between weathering forms,
• distribution / zonation of weathering forms,
• chronological sequences of weathering forms,
• weathering progression, weathering rates,
• stone quality, susceptibility to weathering,
• weathering factors and weathering processes

in dependence on lithotypes, environment and monument characteristics like location, geometry or orientation. The evaluation of weathering forms provides first information on suitable types of interventions in order of monument preservation. Based on monument mapping, complementary in situ measurements and sampling can be well-directed.
Damage categories have been established for subsequent rating of individual weathering damages. Six damage categories have been defined: 0 – no visible damage, I – very slight damages, II – slight damages , III – moderate damages, IV – severe damages, V – very severe damages.
All weathering forms are related to damage categories according to a defined correlation scheme. This correlation scheme "weathering forms – damage categories" considers all weathering forms and their intensities as well as function and historical and artistical value of the stone elements. This requires cooperation of scientists, monument preservation authorities, architects, engineers and restorers.
Damage indices are introduced as consequent tool for conclusive quantification and rating of stone damages. Determination of damage indices is based on quantitative evaluation of damage categories. Damage indices complete a consistent and convincing approach to characterization, evaluation, quantification and rating of visible stone damages. Objectives of damage categories and damage indices are:

• quantification and rating of stone damages for entire stone monuments or individual stone structures,
• comparison and ranking of different monuments regarding their state of damage,
• comparison and ranking of different structures of a monument regarding their state of damage considering age, lithotypes, exposition characteristics, zonation of damages,
• contribution to assessment of weathering factors and weathering processes,
• contribution to comparison and rating of stone quality / stone durability,
• damage prognosis,
• contribution to risk management, judgement of need and urgency of preservation measures,
• judgement / certification and long-term control of monument preservation measures,
• contribution to long-term survey and maintenance of monuments.

ABSTRACT: The rock monuments of the ancient Nabatean city of Petra in Southwest Jordan represent outstanding world cultural heritage. Many hundred monuments were carved from sedimentary bedrocks about 2000 years ago. At many monuments weathering damages are alarming. The World Monument Fund has inscribed Petra into the list of the one hundred most endangered monument assemblies in the world. Precise monument diagnosis is required for characterization, interpretation, rating and prediction of damages and for remedy and sustainable prevention. Systematic studies have been executed at Petra monuments, targeted to comprehensive damage diagnosis. The methodological approach has been tailored to monuments carved from bedrocks. Monument mapping has contributed essentially to damage diagnosis, supplemented by in situ measurements and laboratory tests. Detailed qualitative and quantitative results on weathering state and weathering progression in dependence on stone materials, monument characteristics and environmental influences have been obtained. Damage categories and damage indices have been established for improved rating of weathering damages. They facilitate risk estimation and enhance effective and economic risk management. They indicate urgency of preservation measures and locate those parts of monuments where intervention has to focus on.

KEYWORDS: Weathering, Damage diagnosis, Monument mapping, Damage index

ABSTRACT: At the rock-carved monuments of Petra, damages of different types and intensities can be attributed to weathering. Systematic studies concerning damage diagnosis have been carried out. An important contribution to the damage diagnosis is a detailed lithological survey that has been made. All lithotypes have been studied with respect to their petrographical properties. A new lithostratigraphic classification and the first results of the petrographical analyses are presented.

All natural stone monuments are affected by weathering. At many historical monuments weathering damages are alarming. Worldwide great efforts are undertaken for monument preservation. Precise damage diagnosis is required for characterization, rating, interpretation and prediction of damages and is vital for remedy and sustainable prevention. Quantification of damages has become an important concern of modern scientific approach. In situ investigation of monuments contributes essentially to damage diagnosis. The monument mapping method has been developed as a non-destructive procedure for precise registration, documentation and evaluation of weathering damages. The mapping method can be applied to all stone types and to all stone monuments. This method is focussed on mesoscale of stone weathering (cm to m). This scale of weathering is visible and most applicable for diagnosis at stone monuments. The method meets great international acceptance and is approved as well-tried procedure contributing essentially to improvement of scientific knowledge of stone degradation, to well-founded diagnosis, quantification and rating of damages at monuments and for economic and effective monument preservation.

The evaluation and quantification of weathering damages by means of monument mapping is based on investigation on weathering forms. Weathering forms represent the visible result of weathering processes initiated and controled by interacting weathering factors. By means of monument mapping all weathering forms of monument surfaces are registered according to type, intensity and distribution. Objective and reproducible registration and documentation require a classification scheme of weathering forms. A standard classification scheme has been established, based on investigation at numerous monuments worldwide considering different stone types and environments. Suitable parameters are proposed for classification and quantification of intensities of weathering forms. A computer-programme has been tailored to optimal processing, illustration and quantitative evaluation of mapping information. By means of maps, all weathering forms get exactly located. Zonations of weathering forms can be evaluated as indicators for type and intensity of weathering processes and environmental impacts. Evaluation of weathering forms contributes to assessment of weathering progression and calculation of weathering rates. The influence of lithotypes and monument characteristics such as location, orientation and geometry on susceptibility of monument surfaces to weathering can be stated.

Damage categories have been established for subsequent rating of individual damages. All weathering forms – considering different intensities - get related to damage categories according to defined scheme. Six damage categories have been defined: 0 – no visible damages, I – very slight damages, II – slight damages, III – moderate damages, IV – severe damages, V – very severe damages. Damage categories facilitate risk estimation and risk management. They indicate urgency of intervention. Maps locate those parts of monuments which interventions have to focus on. Quantitative evaluation of damage categories facilitates calculation of extent and costs of interventions, it means an important tool for managing and executing monument preservation works.

In addition to weathering forms and damage categories, damage indices are introduced for conclusive quantification and rating of damages. Application of damage indices further enhances quantitative damage diagnosis at stone monuments. Linear and progressive damage index are defined, both of which are calculated from proportion of damage categories. The linear damage index corresponds to average damage category, whereas the progressive damage index emphasizes proportion of higher damage categories. Both damage indices range from 0 to 5.0 and should always be considered in combination. Damage indices allow ranking of monuments or parts of them with respect to degree of damage, susceptibility to deterioration and urgency of preservation measures. Increasing damage indices correspond to increasing urgency of intervention.

The consequent application of weathering forms – damage categories – damage indices can be considered as an advanced approach to reliable damage diagnosis at stone monuments. It can be recommended for scientific monument studies and as contribution to appropriate monument preservation. Furthermore, it can be applied for long-term survey of monuments and for certification of preservation measures.

The approach to determination of damage indices via weathering forms and damage categories is presented by recent monument studies. Special emphasize is given to significance of damage indices for:

• ranking of different monuments,
• ranking of different parts of an individual monument,
• evaluation of vertical damage profiles,
• certification of preservation measures.

ABSTRACT: Effective and economic preservation measures at natural stone monuments affected by weathering damages require precise damage diagnosis. Systematic studies have been carried out on monuments carved from bedrocks in Petra / Jordan for interpretation of weathering damages and for planning and execution of appropriate preservation measures. Monument mapping is one important method which contributes essentially to the evaluation of weathering damages. Mapping results for Petra monuments are presented.

ABSTRACT: The rock-cut monuments of ancient Petra in Jordan represent an outstanding world cultural heritage. On many of the monuments, damages due to weathering are alarming. Precise diagnosis is needed for the comprehensive characterization, understanding, rating and prediction of damages, and, for remedy and sustainable prevention. Identification, registration, documentation and evaluation of weathering forms are an important contribution to damage diagnosis. Monument mapping has been internationally established as an expert method. Systematic monument mapping has been executed at numerous rock monuments in Petra. The methodological approach and results are presented.

RESUMEN: Muchos monumentos históricos y modernos hechos de piedras naturales, muestran daños por alteración. La planificación y ejecución de medidas de conservación requieren cooperación por parte del propietario del monumento, del restaurador, del arquitecto o ingeniero y de los cientificos. Una diagnosis precisa del daño, representa el fundamento para caracterizar, interpretar y evaluar los daños de alteración y para tomar medidas efectivas económicas de la conservación. La evaluación "in situ" de los daños de alteración significa una contribución importante para una diagnosis fiable de los daños. La cartografia de monumentos es el método único que permite describir, documentar y evaluar superficies completas de piedras con alta precisión según el tipo, intensidad y distribución de los daños. El método fenomenológico nom-destructivo está basado en un esquema de clasificación detallada de formas de alteración. Los métodos de cartografia y esquema de clasificación han sido hechos según la aplicación internacional. Programas especiales de ordenador han sido desarrollados para proceder, illustrar y evaluar cuantitativamente las informaciones de cartografia. La evaluación de los resultados de la cartografia permite indicar la urgencia, tipo y extensión de medidas de conservación y calculo de gastos.Tanbién se puede dirigir mejor los estudios de laboratorios suplementarios y medidas adicionales a tomar "in situ".El método de cartografia se puede recomendar también para la certificación de medidas de preservación y para la observación a lo largo del tiempo de monumentos de piedra natural.

ABSTRACT: The monument mapping method represents a reliable, non-destructive procedure for quantitative characterisation of the weathering state of natural stones at monuments. A detailed classification scheme of weathering forms was developed as basis for this method. The evaluation of the mapping results allows to improve scientific knowledge in the field of stone weathering and can also be applied successfully for the purpose of monument preservation.

KEYWORDS: Natural stone monuments, weathering state, monument mapping, damage categories, monument preservation.

ABSTRACT: Severe weathering damage can be noted on monuments carved from bedrock in ancient Petra / Jordan. Interventions for preservation of this important cultural heritage are necessary. Precise damage diagnosis is required for effective and economic monument preservation. Within the framework of a research project (1996 - 1999) systematic studies are executed in Petra for better understanding of stone weathering and damages of the monuments. Aims of the project and preliminary results are described.

SUCHBEGRIFFE: Zeitzer Sandstein, Kartierung der Verwitterungsformen, Schadensklassen, Salzverwitterung, Modalbestand, Porositätskennwerte, Gesteinsaustausch

ZUSAMMENFASSUNG: Die am ehemaligen Dom St. Peter und Paul zu Zeitz (Sachsen-Anhalt) verwendeten Gesteine, bisher unter der Bezeichnung "Zeitzer Sandsteine" zusammengefaßt, zeigen vielfach erhebliche verwitterungsbedingte Schäden. Auf der Grundlage der Kartierung von Verwitterungsformen an repräsentativen Bauwerksbereichen wird der Verwitterungszustand charakterisiert und bewertet. Anhand der Laborergebnisse zu den petrographischen Eigenschaften wird die Bandbreite der verwendeten Gesteine erläutert. Die Ergebnisse aus Bauwerkskartierung und petrographischer Untersuchung werden gegenübergestellt. Da aufgrund des hohen Schädigungsgrades zahlreicher Werksteine ein Gesteinsaustausch im Rahmen eines Erhaltungskonzeptes in Betracht gezogen werden muß, werden Empfehlungen für Ersatzgesteine vorgestellt.

KEYWORDS: Zeitz sandstone, mapping of weathering forms, damage categories, salt weathering, mineral content, porosity properties, stone replacement

ABSTRACT: The natural stones used at the former Cathedral St. Peter and Paul at Zeitz in Middle Germany today show weathering damages of partly extreme intensity. On the basis of the mapping of weathering forms at representative parts of the monument the state of deterioration is precisely characterized and valuated. The petrographical range of the natural stones – usually called "Zeitz sandstone" – as determined by laboratory investigations is presented. The results obtained from the mapping and from the petrographical investigations are correlated. Due to the high extent of damages at many building stones, stone replacement has to be considered for a restoration concept. Therefore, appropriate natural stones for the replacement of the highly-damaged building stones are recommended.

ABSTRACT: In order to execute appropriate preservation at natural stone monuments it is necessary to know in detail the weathering state of the natural stones used. The mapping of weathering forms is a method, which allows detailed registration and evaluation of type, extent and distribution of apparant damages. A precise classification scheme of weathering forms was developed as basis for the mapping method. The classification scheme is described and the methodology of mapping is explained. Furthermore, examples of mapping results are presented.

KEYWORDS: Natural stone, state of weathering, weathering forms, mapping, damage categories.

VERWITTERUNGSFORMEN AN NATURSTEINBAUWERKEN – KLASSIFIZIERUNG, KARTIERUNG UND AUSWERTUNG

ZUAMMENFASSUNG: Voraussetzung für denkmalgerechte Erhaltungsmaßnahmen an Natursteinbauwerken sind Kenntnisse über den Verwitterungszustand der verwendeten Natursteine. Die Kartierung der Verwitterungsformen stellt eine Untersuchungsmethode dar, mit der Art, Umfang und Verteilung von auftretenden Schäden detailliert registriert und ausgewertet werden können. Als Grundlage für die Kartiermethode wurde ein präzises Klassifikationsschema der Verwitterungsformen entwickelt. Das Klassifikationsschema und die Methodik der Kartierung werden erläutert. Beispielhaft werden Kartierergebnisse dargestellt.

STICHWÖRTER: Naturstein, Verwitterungszustand, Verwitterungsformen, Kartierung, Schadensklassen.

ZUSAMMENFASSUNG: Die Kartierung der Verwitterungsformen stellt in der Bauwerksdiagnostik ein eigenständiges Verfahren dar, mit dem der Verwitterungszustand von Natursteinbauwerken detailliert aufgenommen werden kann. Auf der Grundlage jahrelanger Erfahrungen bei der Entwicklung, Optimierung und Anwendung der Bauwerkskartierung werden Kartier-, Darstellungs- und Auswertetechniken beschrieben. Die Ergebnisse der Verwitterungsformenkartierung können in Hinblick auf denkmalpflegerische, bautechnische und wissenschaftliche Fragestellungen interpretiert werden.

EXPERIENCES WITH MAPPING OF WEATHERING FORMS AT NATURAL STONE BUILDINGS

ABSTRACT: The mapping of weathering forms represents a reliable method for the precise damage diagnosis of natural stone buildings. Techniques of mapping, illustration and evaluation are described on the basis of experiences made in the course of development, optimization and application of monument mapping. The mapping results can be applied successfully for the purpose of monument preservation and they improve scientific knowledge in the field of stone weathering.

ABSTRACT: These four historical monuments of the Mediterranean basin are mainly built up of calcareous rocks, different in age, texture, mineralogy and genesis. Except for the Church of Sta. Marija Ta´Cwerra, more than one lithotype was used, but taking in mind those stones more damaged, a lithotype selection was done for this investigation. Samples from the building, and from quarries in the case Of Malta and Cádiz, were petrographically characterized, and two groups of stones can be considered: a) marbles, b) biolimestones. Marbles and limestones from Eleusis have been mainly degraded by industrial pollution and secondary by marine spray, forming black crusts (in holes and carved blocks) composed of calcite, quartz, mica and gypsum, pink pittings (goethite), and efflorescences (thenardite, halite). The stone from Malta is a very high porosity biosparitic limestone composed of calcite, and glauconite, quartz and iron oxides as accessories, which has been degraded in the building showing less mechanical resistance than that from the quarry stone, and many efflorescences rich in halite with minor nitrate. Also halite was found in quarry stone. Marine spray action is evidenced as the main decay factor for this monument. In Bari Cathedral stones used were low-medium porosity biosparitic/biomicritic limestones, and biomicritic/oomicritic calcarenites. Inside the Building, efflorescences on the cupola contain gypsum, syngenite and nitrates, which can be the result of marine spray and urban pollution. Finally in Cádiz Cathedral, the Estepa limestone, a technically good construction stone according to its physical properties, presents inside the building many occurrences of efflorescences and crusts with calcite, natron, trona and occasional halite indicating the degradating effect of the close marine environment (marine spray, aerosols, percolation waters and saline rising damp). The knowledge of building stones (mineralogy, petrography, physical properties) and the characterization of their alteration products are the first step in the research for understanding stone decay phenomena and their causes.

KEYWORDS: Limestone, marble, petrography, physical properties, alteration products.

ZUSAMMENFASSUNG: Die Gesteinsoberflächen von Baudenkmälern zeigen verwitterungsbedingt Zerstörungen, die in Art und Ausmaß deutlich variieren. Genaue Kenntnisse des Verwitterungszustands sind Voraussetzung, um das Verwitterungsgeschehen an einem Natursteinbauwerk zu verstehen und wirksame Erhaltungsmaßnahmen zu konzipieren. Eine zerstörungsfreie Untersuchung des Verwitterungszustands von Natursteinbauwerken ist mit phänomenologischen und verschiedenen meßtechnischen Verfahren möglich. Phänomenologische Verfahren beruhen auf der visuellen Untersuchung der Gesteinsoberfläche und beinhalten die Registrierung der Verwitterungsformen. Die Kartierung der Verwitterungsformen liefert dabei umfangreiche Zustandsdaten. Diese können flächenbezogen verwaltet, quantitativ ausgewertet sowie in Hinblick auf verschiedene Fragestellungen umgesetzt und dargestellt werden. Basis einer objektiven und reproduzierbaren Registrierung der Verwitterungsformen ist eine Klassifikation, in der alle Verwitterungsformen enthalten und beschrieben sind. Eine solche Klassifikation, die für alle Gesteine nutzbar ist, wird detailliert vorgestellt. An zahlreichen Bauwerken aus Sandstein wurden Kartierungen der Verwitterungsformen durchgeführt und die petrographischen Kennwerte der verbauten Gesteine bestimmt. Anhand des Verwitterungsverhaltens können diese Sandsteine in Gruppen unterschiedlicher Verwitterungsbeständigkeit aufgeteilt werden. Das Verwitterungsverhalten der untersuchten Sandsteine wird dabei hauptsächlich von deren Bindemittel und Porengrößenverteilung bestimmt. Aus der Kombination unterschiedlicher Gesteins- und Expositionstypen ergeben sich verschiedene Bildungsbereiche für Verwitterungsformen. Anhand derer wurde ein Modell zur Entstehung von Verwitterungsformen abgeleitet.

ABSTRACT: Maltese monuments made from Globigerina limestones today show damages of alarming intensity. Salt weathering can be recognized as an important process evoking the stone deterioration. At representative monuments the occurring damages were registered and documented. Laboratory analyses were executed for the determination of characteristical stone properties. Correlations between stone properties and weathering behaviour were deduced and, furthermore, statements with regard to monument preservation works.

ABSTRACT: Main structural stones of Cartuja of Seville are calcarenites from Puerto de Santa Maria (Cádiz) and biomicrosparitic limestones from Pantano Torre del Aguila (Sevilla). The weathering forms usually observed in the monument were loss of material, grain disaggregation, fissuring, crusts and efflorescences. Stones from monument original quarries, altered under accelerated ageing tests (wetting-drying and salt crystallization) showed similar weathering forms to those of the monument. Two preservative products (Tegovakón, ethyl silicate, and Tegosivin, silicone) were applied to quarry stones to check their efficacy. The most effective treatment was Tegosivin, because there was no modification in stones after the alteration tests carried out in the lab.

KEYWORDS: Limestone, calcarenite, weathering forms, treatment efficacy, Cartuja of Seville.

SUMMARY: The consolidation of weathered tuff material is problematical in most cases due to their unusual pore size distribution. For the case of the Rano Raraku tuff of Easter Island under study, the distribution shows trimodal pattern. The problem arises because the smallest capillary pores are not reached by the liquid, gel-forming consolidants, such as silicate esters, which mainly fills the larger capillary pores. Thus, the weakened area around the smallest capillary pores is not reinforced. Furthermore, the enormous rates of hygric swelling observed for this material contribute to curtail the durability of this type of consolidation treatment.
This study tested commercially available and modified silicate esters, as well as newly developed anti-swelling agents on Rano Raraku tuff samples taken from the quarry and from broken moai (statues). Treated and untreated specimens were studied by SEM and their pore size distribution and specific surfaces determined. Their hygroscopicity, hygric dilation and their drill resistance were also measured. Both treated and untreated specimens were then subjected to artificial weathering, simulating an exaggerated Easter Island sub-tropical climate, and the studies and aforementioned measurements repeated. The results obtained are discussed and the possible durability of the treatments assessed.

KEYWORDS: Natural stone building, mapping, natural stone, weathering state, weathering form, classification scheme of weathering forms, mapping methodology presentation of mapping results, damage category

ABSTRACT: In order to execute preservation measures at natural stone buildings it is necessary to know in detail the weathering state of the stones used. The mapping of weathering forms is a method, which allows the registration of type, extent and distribution of apparent weathering damages. It requires a classification scheme of weathering forms. The classification scheme and its application is explained. Furthermore, the methodology of mapping is described. Mapping results are presented by means of examples.

SUCHBEGRIFFE: Natursteinbauwerk, Bauwerkskartierung, Naturstein, Verwitterungszustand, Verwitterungsform, Klassifikationsschema der Verwitterungsformen, Kartierungsmethodik, Darstellung der Kartierergebnisse, Schadensklasse

ZUSAMMENFASSUNG: Für die Durchführung denkmalgerechter Erhaltungsmaßnahmen an Natursteinbauwerken sind Kenntnisse über den Verwitterungszustand der verwendeten Gesteine erforderlich. Die Kartierung der Verwitterungsformen stellt eine Untersuchungsmethode dar, mit der Art, Umfang und Verteilung der auftretenden Schäden registriert werden können. Voraussetzung ist ein Klassifikationsschema der Verwitterungsformen. Das Klassifikationsschema wird in seiner Anwendung erläutert und die Methodik der Kartierung beschrieben. Beispielhaft werden Katierergebnisse dargestellt.

ZUSAMMENFASSUNG: Das Verwitterungsverhalten der am Belvedere auf dem Pfingstberg in Potsdam verbauten Rüdersdorfer Schaumkalke wurde untersucht. Die eingesetzten Untersuchungsverfahren werden beschrieben sowie exemplarisch Untersuchungsergebnisse dargestellt und erläutert. Ein erster Teil umfaßt die Kartierung der auftretenden Verwitterungsformen auf der Grundlage eines entwickelten Klassifikationsschemas. Die Kartierergebnisse dokumentieren dabei Art, Intensität und Verteilung der Verwitterungsschäden und belegen eine bisher gute Verwitterungsbeständigkeit der Kalksteine. Der zweite Teil beinhaltet die petrographische Charakterisierung ausgewählter Bauwerksproben sowie die Bestimmung verwitterungsrelevanter Gesteinskennwerte. Den Schwerpunkt der Untersuchungen bildet die Porenraumanalyse. Durch Anwendung direkter und indirekter Verfahren ist eine realitätsnahe Beschreibung des Porengefüges möglich. Die Porositätskennwerte erlauben eine Differenzierung der Rüdersdorfer Schaumkalke und liefern Hinweise auf ein porositätsspezifisches Verwitterungsverhalten.

RUEDERSDORF "SCHAUMKALK" AS CONSTRUCTION MATERIAL - POROSITY CHARACTERISTICS AND WEATHERING BEHAVIOUR OF BUILDING STONES IN THE BELVEDERE ON THE PFINGSTBERG, POTSDAM

ABSTRACT: Ruedersdorf limestone was used for the construction of the Belvedere on Pfingstberg in Potsdam, fragment of a small castle built in mid-19th century. The weathering behaviour of the limestone was studied. The methods of investigation applied are described. Results are discussed and presented by means of examples. The first part of this report is concerned with the mapping of weathering forms using a new classification scheme. The resulting maps illustrate type, intensity and distribution of the weathering damages observed and indicate a rather good weathering resistance of the limestone. In a second part the petrographical classification of the limestone is given and other stone characteristics relevant to weathering. The data obtained from porosity analyses are of special importance. The realistic characterization of stone porosity was achieved by combining results from direct and indirect measuring procedures. On the basis of the porosity data varieties of the Ruedersdorf Schaumkalk were recognized and the respective weathering behaviour was deduced.

ZUSAMMENFASSUNG: An der Grabkapelle des Heiligen Grabes in Görlitz erfolgte eine Kartierung und Bewertung von Verwitterungsschäden des Schlesischen Kreidesandsteins, der aus Vorkommen der unmittelbaren Umgebung von Görlitz stammt. Untersuchungen zu Petrographie und Porositätsverhältnissen erbrachten erstmalig Daten zu diesem regional bedeutsamen Baugestein und im Vergleich von Steinbruch- und Objektmaterial eine Klärung der Herkunft der Bausteine. Die Bestimmung hygrischer Kennwerte als Voraussetzung für Konservierungsmaßnahmen erfolgte an Bohrkernmaterial und zerstörungsfrei am Objekt. Die vorliegenden Ergebnisse bilden die Grundlage für die Optimierung von Restaurierungsmaterialien und –techniken.

SUCHBEGRIFFE: Schlesischer Kreidesandstein, Steinbrüche, Kartierung der Verwitterungsformen, Schadensbewertung, Modalbestand, Porositätskennwerte, hygrische Kennwerte.

ABSTRACT: At the Chapel of the Holy Tomb in Görlitz a mapping and evaluation of the weathering damages were made for the Cretaceous Silesian Sandstone coming from quarries in the surroundings of Görlitz. Investigations on petrography and porosity characteristics for the first time supplied data on this regionally important building material. Furthermore, the comparison between stone material from the quarries and from the Chapel proved the origin of the building stones. The determination of hygric properties as a basic requirement for conservation measures was made at drill cores as well as in an non-destructive way at the monument.The available results provide the basis for optimizing restoration materials and techniques for the monument.

KEYWORDS: Cretaceous sandstone from Silesia / Poland, quarries, mapping of weathering forms, evaluation of damages, mineral content, porosity properties, hygric properties.

ABSTRACT: The Demeter Sanctuary in Eleusis, in the greater Athens area in Greece, constructed between the late Helladic and the classic (Periclean) period demonstrates a variety of building stones characteristic of the different lithological formations which comprise the complicated geological structure of Attica. In the present work analysis and classification of lithotypes is taking place by employing mineropetrographic studies, physical, mechanical and microstructural analysis of the porous system of the various lithotypes, in order to assess and evaluate their susceptibility to weathering in the intense marine and polluted atmosphere of Eleusis. Grey micritic limestone, yellow limestone, grey biomicritic limestone, yellow brown limestone and yellow-brown fossiliferous dolomite with origin from the subpelagitian unit of Eleusis area and white (Pentelic) and white-grey marble from the autochthonous Attico-Cycladic crystalline complex have been identified. The building stones present in general low porosity, mainly of interparticle type as well as good physical and mechanical properties matching their textural and structural characteristics, the marble group attaining the highest apparent density and the lowest water absorption, in comparison with the limestone group. The wave velocity, depending on the homogeneity of the stone mass, appears to be higher for the relevant low porous and fine-grained limestone, that presents no microstructural networks, while on the contrary the most porous limestone presents lower values. Different values of physical and mechanical properties measured for the same rock type indicate its alteration due to anisotropy and/or weathering. The texture of the building stones matches the structure of the pore spaces demonstrating the preferential routes for weathering.

COMPENDIO: Il santuario di Demetra in Eleusi, in Grecia, nella Regione di Atene, costruito tra il periodo Tardo-Elladico e quello Classico (di Pericle), mostra una grande diversità di pietre da costruzione, caratteristiche delle diverse formazioni litologiche della complicata struttura dell´Attica. In questo lavoro è stata eseguita l´analisi e la classificazione die litotipi, impiegando studi mineralogico-petrografici ed analisi fisiche, meccaniche e microstrutturali die sistemi porosi die diversi litotipi, allo scopo di mettere in evidenza e valutare la loro suscettibilità all`azione del tempo meteorologico, nell`aria marina fortemente inquinata di Eleusi. Valori differenti delle proprietà fisiche e meccaniche misurati per lo stesso tipo di roccia ne mettono in evidenza l´alterazione dovuta all´anisotropia e/o all´azione del tempo. La tessitura delle pietre da costruzione si accorda con la struttura degli spazi, dimostrando cosi i percorsi preferenziali dell´azione del tempo,

ABSTRACT: Natural stones are characterized by a "chaotic" pore structure. This pore space is the area where weathering processes mainly take place. Classification models allow a grouping of the pore space in genetic and geometric aspects. It is very difficult to measure the pore space due to different porosity properties and to varying pore sizes. Only the combination of direct and indirect measurement methods permits to establish quite realistic pore space models. The results of porosity investigations at different sandstones are presented. So a distinction can be made between different porosity types of stones. Furthermore the weathering behaviour of these stones at the building and in various laboratory tests is evaluated. The weathering behaviour of the stones is controlled by porosity properties.

RÉSUMÉ: Les roches naturelles sont caractérisées par une porosité interconnectée chaotique. Cette porosité interconnectée est l'endroit dans lequel des procès de désagrégations par des intempéries se déroulent de manière favorable. Des schémas de classifications permettent un classement de la porosité d'après des aspects génétiques et géométriques. La mesure de la porosité interconnectée est trés difficile en raison des différents caractères de porosités et des grandeurs variés de pores. La représentation de modèles réalistes de porosités interconnectés n'est possible que par l'utilisation de méthodes directes et indirectes de mesurages. Les résultats d'analyses de porosités seront présentés pour différents grès. Ils permettent le classement des pierres en groupes de porosité. Désormais, l'évaluation du comportement d'altération de ces pierres dans des bâtiments et dans différents tests en laboratoires sera faité. Le comportement d'altération des pierres sera controlé par les caractères de porosités.

SUCHBEGRIFFE: Porosität, Porositätskennwerte, Porositätsklassifikation, Porenmodell, Porengröße, Porentypen, Porositätsgruppen (in)direkte Meßmethoden, Methodenvergleich, Verwitterungsverhalten, Kristallisationsdruck, Salzsprengung

ZUSAMMENFASSUNG: Gesteine zeichnen sich durch eine "chaotische" Porenraumstruktur aus. Diese beeinflußt und steuert die im Gestein ablaufenden Verwitterungsprozesse. Der Einsatz unterschiedlicher Klassifikationsschemata ermöglicht das Ordnen und Beschreiben des komplex aufgebauten Porensystems nach geometrischen und genetischen Gesichtspunkten. Die Messung der Porenkennwerte erfordert die kombinierte Anwendung von direkten und indirekten Verfahren. Die zur Porenraumcharakterisierung von Natursteinen am häufigsten angewendeten Verfahren Lichtmikroskopie und Elektronenmikroskopie in Kombination mit der Bildanalyse sowie Quecksilberporosimetrie und Stickstoffsorption werden vorgestellt. Am Beispiel von Sandsteinen wird ein Abgleich der Meßergebnisse unterschiedlicher Verfahren durchgeführt. Sandsteine können aufgrund ihrer Poreneigenschaften in Gruppen eingeteilt werden, die ein vergleichbares Verwitterungsverhalten bei Frost-Tau-Wechsel und Salzbelastung aufweisen. Die bei Salzverwitterungsprozessen im Porenraum auftretenden Kristallisationsdrucke werden berechnet. Das Verhalten von ausgewählten Sandsteinen durch diese Beanspruchung wird diskutiert.

KEYWORDS: Porosity, porosity characteristics, porosity classification, pore model, pore size, pore types, porosity groups, (in)direct measuring methods, combined evaluation, weathering behaviour, crystallization pressure, salt stress

ABSTRACT: Rocks are characterized by a "chaotic" pore structure. This structure influences and controls the weathering processes taking place in the rocks. Classification schemes allow the description of the complex pore system according to geometric and genetic aspects. The measurement of the pore characteristics requires the combination of direct and indirect procedures. In this paper those procedures are presented which are most frequently used to characterize the pore space of natural stones, such as microscopy and electron microscopy in combination with image analysis, mercury porosimetry and nitrogen sorption. Sandstones are taken as examples for a combined evaluation of the measuring results of different methods. Owing to their pore characteristics sandstones can be devided in groups showing comparable weathering behaviour at frost-thaw-cycles and salt stress. The crystallization pressures occurring with salt weathering processes are calculated. The behaviour of selected sandstones under salt stress is discussed.

ABSTRACT: A preliminary approach to the case of the Demeter Sanctuary of Eleusis demonstrates the interdisciplinary methodology under development, according to the R & D Programme in the field of "environment"(Contract No. EV5V-CT92-0102 between EEC and CUM), for the analysis of marine spray and polluted atmosphere as factors of damage to monuments in the Mediterranean Coastal Environment. Analysis and classification of lithotypes and weathering patterns, in relation to the environmental and microenvironmental factors under monitoring, is taking place by employing minero-petrographic studies, physical, mechanical and microstructural analysis of the porous stone system on the various stone materials, computerised weathering analysis as well as scanning electron microscopy and microanalysis on the crust profiles along with chemical wet analysis.
The obtained results of the first work-phase allow for a preliminary approach to the problems. Five different carbonate rocks, grey-micritic limestone, white marble, white-grey marble, yellow limestone and biomicritic grey limestone are identified as building materials presenting in general low porosity, mainly of interparticle type, and physical and mechanical properties matching their textural and structural characteristics. Decay patterns evolve in selective relation to the intrinsic factors of the building stones, disaggregation and biological attack evolving preferentially at the interparticle pore spaces.
For a given substrate, and specifically for the white marble, the influence of the heavily polluted atmosphere in a marine environment is varying, resulting in several weathering patterns, mainly in the form of crusts, according to both extrinsic (microenvironment) and intrinsic factors.
However, a further development is urged to register weathering on a spatial, general and detailed mapping as well as to correlate the under monitoring environmental factors to the stone decay patterns and damage level and to develop the proper conservation interventions.

ABSTRACT: The destructive impact of biodeterioration processes on the structural substance of historical monuments, and distinct individual objects of art made of various kinds of materials, means that conservation and restoration practice requires adaquate and non-hazardous methods for their sterilisation and preservation. The studies presented here will show how highly microbially contaminated carbonate rocks and different quartzitic sandstones, mainly originating from archaeological diggings of Roman settlements in Trier (Germany), were completely sterilised by ethylene oxide without any measurable changes to the mineralogical structure and physical characteristics. In view of the fact that several biocides have recently been banned, and that ethylene oxide is regarded as highly toxic, this commercial procedure is under the close control of health authorities. However, it seems to be one of the few methods with some future in the decontamination of objects of the cultural heritage. The application of the documented results for a successful anti-microbial treatment of other objects of art is discussed.

KEYWORDS: Biodeterioration, carbonate rock, sandstone, arcose, conservation, anti-microbial treatment, ethylene oxide (ETO).

ZUSAMMENFASSUNG: Bauwerkskartierungen wurden an einem Teilbereich der Nordfassade der Kollegiale zu Thann durchgeführt. Art, Umfang und Verteilung der verwendeten Gesteine und ihre Verwitterungsformen konnten exakt dokumentiert werden. Hauptbaumaterial ist Karbonatgestein des Typs "Rouffach", das in mehrere Varietäten differenziert wurde. Die Kartierung der Verwitterungsformen wurde auf der Grundlage eines detaillierten Klassifikationssystems vorgenommen. Hierbei handelt es sich um ein selbstentwickeltes Untersuchungsverfahren zur präzisen, reproduzierbaren Schadensregistrierung. Mit Hilfe von Laboruntersuchungen konnte die große Bandbreite der petrographischen Eigenschaften der "Rouffac"-Karbonatgesteine erfaßt werden. Eine genaue Charakterisierung des Porenraumes wurde durch die Kombination verschiedener Meßverfahren erreicht.

ÉTAT D´ALTÉRATION ET CARACTÉRISTIQUES PÉTROGRAPHIQUES DES PIERRES DE LA COLLÉGIALE DE THANN EN FRANCE

RÉSUMÉ: A l´aide d´une cartographie du monument relative à une partie de la facade nord de la Collégiale de Thann, il a été possible de documenter précisément le type, la quantité et la répartition des pierres utilisées ainsi que le type d´altération. Le matériau principal de construction est la pierre de carbonate du type "Rouffach" qu´on peut classer en plusieurs variétés. Au moyen d´une cartographie des formes d´altération basée sur une système de classification détaillée, on a appliqué notre propre méthode d´investigation pour l´enregistrement précis et reproductible des dégâts. Des analyses en laboratoire ont permis d´enregistrer les différentes caractéristiques pétrographiques des pierres de carbonate du type "Rouffach". Quant aux caractéristiques de porosité, on a montré qu´il est possible d´obtenir une caractérisation exacte du volume des pores en utilisant la combinaison de différentes méthodes de mesure.

WEATHERING STATE AND PETROGRAPHIC PROPERTIES OF STONES AT THE THANN COLLEGIATE CHURCH IN FRANCE

ABSTRACT: By means of monument mapping at a part of the northern facade of the Thann Collegiate Church, the type, quantity and distribution of the stones used and its weathering forms could be precisely documentated. Main building material is carbonate rock of the "Rouffach" type, which could be differentiated in several varieties. The mapping of weathering forms on the basis of a detailed classification scheme was applied as a selfly-developed investigation method for precise and reproducible damage assessment. By means of laboratory tests the large range of the petrographical properties of the "Rouffach" carbonate rocks could be recorded. Referring to the porosity properties it was clearly shown that only the combination of various measuring procedures allows a relatively precise characterization of the pore space.

ZUSAMMENFASSUNG: Das Verwitterungsverhalten von Buntsandsteinen, Schilfsandsteinen und Rhätsandsteinen wurde an zwölf historischen Natursteinbauwerken untersucht. Die an den Bauwerken auftretenden Verwitterungsformen werden beschrieben. Für jede Sandsteingruppe wird eine Bauwerkskartierung vorgestellt und quantitativ ausgewertet. Die typischen Verwitterungsmerkmale jeder Sandsteingruppe werden charakterisiert. Mineralzusammensetzung und Porositätskennwerte der Bauwerksgesteine werden bestimmt. Typische petrographische Eigenschaften der drei Sandsteingruppen werden anhand von Einzelproben erkäutert. Die Ergebnisse der Bauwerkskartierungen und der petrographischen Untersuchungen werden gegenübergestellt und bewertet.

SUCHBEGRIFFE: Sandsteinbauwerke, Buntsandsteine, Schilfsandsteine, Rhätsandsteine, Verwitterungsverhalten, Kartierung der Verwitterungsformen, Modalbestand, Porositätskennwerte.

ABSTRACT: The weathering behaviour of Bunter sandstones, Schilf-sandstones and Rhaetic sandstones was studied at twelve historical monuments made from natural stone. The weathering forms occurring at the monuments are described. For each sandstone group a monument mapping is presented and quantitatively evaluated. The typical weathering characteristics of each sandstone group are pointed out. Mineral composition and porosity data of all three sandstone groups are explained by means of individual samples. The results of the monument mappings and the petrographic investigations are compared and evaluated.

KEYWORDS: Sandstone buildings, Bunter sandstones, Schilf-sandstones, Rhaetic sandstones, weathering behaviour, mapping of weathering forms, mineral content, porosity properties.

ZUSAMMENFASSUNG: Historische Natursteinbauwerke erfordern Erhaltungsmaßnahmen, die auf die jeweiligen Baumaterialien und deren Schadenszustand abgestimmt sind. Die dazu notwendigen Informationen liefern die Bestands- und Zustandsaufnahme, die man mit verschiedenen Verfahren am Bauwerk und im Labor vornehmen kann. Dabei müssen Art und Umfang der verwendeten Natursteine und Mörtel sowie Typ und Verteilung der auftretenden Schäden ermittelt werden. Weiterhin sind die Materialkennwerte zu bestimmen und deren verwitterungsbedingte Veränderungen zu erfassen. In der vorliegenden Arbeit werden wichtige Verfahren zur Bestands- und Zustandsaufnahme vorgestellt. Als aussagekräftiges Untersuchungsverfahren kann die Bauwerkskartierung angesehen werden, mit der auch in großen Fassadenbereichen sowohl die verwendeten Natursteine als auch Mörtel aufgenommen und die Schadensformen dokumentiert werden können. Die Kartierergebnisse sind Grundlage für die Schadensbewertung und für die Interpretation der mit anderen Verfahren ermittelten Untersuchungsergebnisse. Sie sind Voraussetzung für denkmalgerechte Erhaltungsmaßnahmen.

ABSTRACT: The weathering state and material properties of the famous soapstone sculptures in Congonhas and the quartzite masonry of two important baroque monuments in Ouro Preto were investigated. The weathering forms occurring were registered and mapped by means of a classification scheme. The characteristic weathering forms are described. Mapping results are presented as an example for each investigated object. Samples from the monuments and comparable material from quarries were studied in the laboratory. the data obtained enabled the characterization of the stones. Correlations between laboratory results and weathering behaviour of the stones are also shown.

KEYWORDS: Soapstone, quartzite, weathering forms, mapping, mineral composition, porosity.

ZUSAMMENFASSUNG: Am Naumburger Dom wurden während der verschiedenen Bauperioden fast ausschließlich Kalksteine aus der näheren Umgebung Naumburgs verwendet. Das Gestein zeigt heute eine Vielzahl verschiedener Verwitterungsformen, die teilweise direkt den Einfluß der hohen Schadstoffbelastung der Luft in der Region erkennen lassen. Der Verwitterungszustand wurde photographisch und mit Hilfe von Kartierungen der Verwitterungsformen dokumentiert. In weiteren Arbeitsschritten wurden bauwerksklimatische Messungen sowie Ultraschallmessungen an bruchfrischen Werksteinen und im Vergleich hierzu an verwitterten Bauwerksteilen vorgenommen. Die Ultraschallmessungen ermöglichen die Quantifizierung des Schadenszustandes. An Proben von bruchfrischen Werksteinen und an Bauwerksproben wurden im Labor die verwitterungsrelevanten petrographischen Kennwerte bestimmt. Der exakten Analyse des Porenraums, als Wirkungsort der Verwitterungsprozesse, wurde besondere Beachtung geschenkt.

SUCHBEGRIFFE: Kalkstein, Verwitterungsformen, Kartierung, Gesteinsoberflächentemperaturen, Ultraschallmessung, Porositätskennwerte.

ABSTRACT: For the construction of the Naumburg cathedral nearly exclusively limestones from the surrounding were used during all different construction periods. Today the stone shows numerous different weathering forms which prove the influence of the noxious air pollution in this region. The weathering state was documented by means of photos and mapping of the weathering forms. Furthermore, measurements of the building climate as well as ultrasonic measurements at unweathered and weathered building stones were executed. The ultrasonic measurements allow a quantification of the state of damage of the building parts. At the building samples and at the samples of unweathered stones petrographic characteristics – being relevant for weathering – could be obtained. The exact analysis of the pore space where weathering processes mainly take place has been considered in particular.

KEYWORDS: Limestone, weathering forms, mapping, stone surface temperature, ultrsonic measurements, porosity characteristics.

ABSTRACT: Calcarenite from Puerto de Santa Maria, a stone widely used in historic monuments of Western Andalucia, does not show important porosity variations after five hundred years of weathering in the Cartuja of Seville. However, its macroporosity (10-300µm) falls from 14% to 10% after a treatment with Tegovakon, an ethyl silicate harder, because of amorphous silica is deposited into the big pores, and also the surface area of micropores increases due to the silica gel presence, but the porosity of the stone treated with Tegosivin, a water repellent, does not vary. Nevertheless, both treatments lead to an abruptly decreasing of water absorption. In order to improve the technical characteristics of the Puerto stone as building material, a previous protection treatment with a harder followed by a water repellent is suggested.

KEYWORDS: Stone decay, calcarenite, porosity, protection treatments.

ZUSAMMENFASSUNG: Standardisierte Untersuchungsverfahren dienen der Bestimmung des Verwitterungsverhaltens von Natursteinen bei isolierten Beanspruchungsarten. Für 22 Gesteinsvarietäten wird das Verhalten bei einem Frost-Tau-Wechsel- und bei einem Salzversuch untersucht. Die Ergebnisse werden zusammenfassend dargestellt und eine Rangfolge der Verwitterungsbeständigkeit der Gesteinsvarietäten gegenüber den getesteten Beanspruchungsarten aufgestellt. Die kombinierte Frost-Tau-Wechsel- und Salzverwitterung stellt einen sehr wichtigen Typ der Natursteinverwitterung in unseren geographischen Breiten dar. Mit dem Ziel, eine möglichst gute Anpassung an natürliche Gegebenheiten zu erreichen, ist ein Programm mit einem Zeitverkürzungsfaktor 1:6 zur Simulation dieses Verwitterungstyps auf der Grundlage meteorologischer Daten entwickelt worden. In vier Programmabschnitten werden die jahreszeitlichen Schwankungen von Klimaelementen und ihre Abfolge berücksichtigt. Der Salzeintrag erfolgt über die kapillare Aufnahme einer 0,25 m NaCl-Lösung. Der Simulationsversuch ist beispielhaft am Sander Schilfsandstein und am Obernkirchener Sandstein durchgeführt worden. Die Verwitterungsformen werden phänomenologisch beschrieben. Die im Versuch entstandenen Verwitterungsformen sind mit Verwitterungsformen am Bauwerk vergleichbar. Simulationsversuche stellen somit ein wichtiges ergänzendes Hilfsmittel zur Bestimmung des Materialverhaltens dar.

SUCHBEGRIFFE: Natursteine, Verwitterungsverhalten, Verwitterungsformen, Frost-Tau-Wechsel- und Salzverwitterung, Verwitterungssimulation.

ABSTRACT: Standardised test methods serve to determine the weathering behaviour of natural stones in terms of isolated types of stress. The weathering behaviour of 22 stone varieties is investigated using frost-thaw cycle and salt tests. The results from both are presented together, and a table is drawn up ordering the resistance of the stone varieties to weathering induced by the types of stress under investigation. The combined effect of the frost-thaw cycle and salt weathering constitutes a very important type of natural stone weathering in our part of the world. In order to attain as close a parity as possible to natural conditions, a programme for simulating this type of weathering has been developed on the basis of meteorologicalfactors, the time reduction factor being 1:6. Variations in seasonal climatic elements and sequences are considered under the four respective sections of the programme. The salt content results from the capillary absorption of a 0.25 m NaCl solution. The simulation experiment is exemplified by work carried out on Sand Schilf-Sandstone and Obernkirchen Sandstone. The weathering forms are described phenomenologically. The weathering forms resulting from the work are comparable with those encountered at the building. Simulation experiments therefore represent an additional aid in determining material behaviour.

KEYWORDS: Natural stone, weathering behaviour, weathering forms, frost-thaw cycle test, combined frost-thaw cycle and salt weathering, crystallization test, weathering simulation.

ABSTRACT: In order to provide nature-adapted simulation tests meteorological data as well as information on the building climate are essential. Measuring schemes which have been tested on different buildings are presented. Results of long-term measurements on buildings are exemplarily shown by means of the Cathedral of aachen. They are compared with meteorological data. To further explore the frost-thaw cycle and salt-resistance in terms of isolated types of stress, a methodology was developed to check the combined stress of the frost-thaw cycle and salt because building stones in our part of the world are approached by combined weathering processes. In order to attain a good correspondence with natural factors, a programme for the simulation of these weathering types was devised on the basis of meteorological data. The programme comprised four sections in which seasonal climatic elements and sequences were considered. Climatic values at the building were also used when drawing up the programme. The time shortening factor used is 1:6. As well as frost-thaw cycle, soaking and drying out were also incorporated into the simulation programme. The salt content resulted from the capillary adsorption of salt solution. Illustrative results of the different kinds of simulation experiments are presented for several stone varieties. The weathering forms are described phenomenologically. Those arising from the experiment simulating the combination of frost-thaw cycle and salt weathering are comparable to those found on buildings. The weathering profiles of test and building samples are analysed using mercury porosimetry and image analysis. Also these results show especially for the experiment simulating the combined frost-thaw- and salt weathering a good correlation with the weathering profiles found on buildings. Simulation experiments on combined frost-thaw and salt weathering, therefore, provide an important additional aid for determining material behaviour.

KEYWORDS: Natural stones, weathering forms, frost-thaw cycle test, salt crystallization test, building climate, combined frost-thaw cycle and salt weathering.

RÉSUMÉ: Pour établir des essais de simulation adaptés à la nature des informations sur le climat des monument – à part des dates metéorologiques – sont indispensables. On peut obtenir ces informations par de différents modèles de mesure. Des mesures déjà examinées à de différents monuments sont présentées et des résultats des mesures à longue termes à un monument sont exposés comme exemple à la Cathédral d´Aix-la-Chapelle. Ces mesures sont comparées avec des dates meteorologiques. Pour compléter les essais standardisés de l´action des cycles de gel et de dégel et la résistance au sel aux différent efforts, une méthode fut developpé pour examiner la combinaison de l´action des cycles de gel et de dégel et l´altérationau sel, parce que les roches naturelles employées comme matériel de construction sont attaquées par des processus d´altération combinés dans nos regions geographiques. Avec le but d´obtenir une bonne adaptation à des données naturelles on a developpé une programme de simulation de ces types d´altération basant sur des dates metéorologiques. En quatre sections de programme les oscillations saisonales des élements de climat on été considérées. Même des charactéristiques du climat du bâtiment ont été utilisées pour établir le programme. Le facteur pour réduire le temps est 1:6. Dans le programme de simulation on ne considère pas seulement l´action de cycles de gel et de dégel et altération au sel, mais aussi l´humidification et le séchage. La pénétration du sel s´effectue par l´absorption capillaire des solutions du sel. Les résultats de différents essais de simulations sont présentés pour quelques roches exemplaires. Les formes d´altération sont décrit phénomenologiquement. Les formes d´altération obtenues dans l´essai de combinaison l´action des cycles de gel et de dégel cycle et altération au sel sont comparables à des formes d´altération au bâtiment. Enplus, on établit une classification selon le degré de l´altération. Les profiles d´altération des échantillons du test et du bâtiment sont analysées à l´aide de la porosimétrie au mercure et de la microscopie avec analyse de l´image selon les charactéristiques de structure. Aussi ici les résultats de l´action des cycles de gel et de dégel et altération au sel sont plus pareils à des profiles d´altérationproduites par un traitement isolé. Des essais de au sel présentent ainsi un moyen important pour déterminer le comportement du matériel.

KURZFASSUNG: Sandsteine stellen in Mitteleuropa die am häufigsten verwendeten Naturwerksteine dar. Die aus ihnen errichteten, kulturhistorisch wertvollen Bauwerke zeigen Verwitterungsschäden, die dringend Restaurierungsmaßnahmen erfordern. Dazu sind Kenntnisse der Verwitterungsprozesse notwendig. Der Porenraum der Gesteine steuert dabei maßgeblich das Verwitterungsverhalten. Sandsteine besitzen ein breites Spektrum unterschiedlicher Porositätseigenschaften, die schwierig zu messen sind. Für die Messung der Porenstrukturen müssen verschiedene Verfahren kombiniert eingesetzt werden. Dies erlaubt die Erstellung von Porenmodellen, die eine porositätsbezogene Klassifizierung der Gesteine ermöglichen. Es werden die Ergebnisse von Porositätsuntersuchungen an unterschiedlichen Sandsteinen vorgestellt und diskutiert. Weiterhin wird das Verwitterungsverhalten dieser Gesteine am Bauwerk und in verschiedenen Labortests eingeschätzt. Es wird gezeigt, daß es Zusammenhänge zwischen den Porositätsklassen der Gesteine und ihrem Verwitterungsverhalten gibt.

POROSITY PROPERTIES AND WEATHERING BEHAVIOUR OF SEDIMENTARY NATURAL STONES

SUMMARY: Sandstones are the most frequent natural building stones in Middle Europe. The historically valuable monuments made from these stones show weathering damages which require urgent conservation measures. Knowledge of weathering processes is necessary. The pore space of stones is responsible for the weathering behaviour. Sandstones have a large variety of porosity properties, which are difficult to measure. In order to measure the pore structures a combination of various procedures has to be applied. This allows to establish pore models enabling us to classify the stones according to porosity. The results of porosity investigations at different sandstones are presented and discussed. Furthermore, the weathering behaviour of these stones at the building and in various laboratory tests is evaluated. The correlations between the porosity types of the stones and their weathering behaviour are shown.

ABSTRACT: For many centuries volcanic tuffs from western Germany have been used in the construction of important historic buildings. These have suffered severe weathering damage, calling for immediate preservation actions. The effectiveness of these actions depends on accurate knowledge of the causes and state of the damage. By mapping the building using a classification scheme of tuff weathering forms it is possible to make an objective and reproducible description of the damaged condition. The results of mapping a minster from the Middle Ages are given. Characteristic values relevant to weathering are also presented for Rhenish tuffs and an Easter Island tuff. The behaviour of tuffs according to laboratory tests is discussed. Pore space analysis constitutes an important method for recording the state of weathering.

ABSTRACT: Rhensish tuff is a widespread, weathering-susceptible natural stone which has been used for constructing important historical buildings in western Germany and neighbouring countries since Roman times. The poor condition of these tuff buildings requires immediate protection measures. The effectiveness of such measures depends upon an accurate knowledge of the causes and state of the damage. A method is presented which enables the exact recording of the state of damage and gives information on the exogenetic factors producing the deterioration of this natural stone. Selected results from building investigations and laboratory tests are explained.

LE TUF DE LA RHÉNANIE – UNE PIERRE NATURELLE TRÈS RÉPANDUE ET SENSIBLE À L´ALTÉRATION

RÉSUMÉ: Le tuf de la Rhénanie est une pierre naturelle très répandue et très sensible à l´altération. Elle a déjà été utilisée dès la période romaine pour la construction des bâtiments historiques importants. Le mauvais état de ces bâtiments en tuf exige à prendre des mesures de protection et d´assainissement immédiates. L´efficacité de telles mesures dépend de la connaissance parfaite de l´état et de la cause des dégâts. Une méthode sera présentée qui permet un enregistrement de l´état des dégâts des tufs et qui donne des renseignements sur les facteurs exogènes qui provoquent principalement l´altération des pierres. Quelques exemples choisis portant sur les études des bâtiments et sur le essais de laboratoire seront expliqués.

KURZFASSUNG: An 24 sedimentären Naturwerksteinen wurden neben Verwitterungsformbeschreibungen petrographische und gesteinsphysikalische Untersuchungen vorgenommen. Einen Schwerpunkt bildeten hierbei Mikrogefügeuntersuchungen mit Hilfe der Quecksilberporosimetrie und weiterer Vergleichsverfahren. Auf der Basis der aus diesen Untersuchungen resultierenden Ergebnisse wurden die Gesteine anhand ihrer Porositätsmerkmale klassifiziert. Weiterhin wurden an allen Gesteinen Wasseraufnahmeversuche und Wasserabgabeversuche sowie Simulationsversuche zur Frost-Tauwechselverwitterung und Salzverwitterung durchgeführt und die erzeugten Verwitterungsmerkmale registriert. Die durch die Verwitterungsprozesse hervorgerufenen Materialveränderungen wurden durch Porositätsuntersuchungen quantitativ erfaßt. Die hier vorgestellten Untersuchungsergebnisse zeigen, daß das Hohlraumgefüge der Gesteine einen entscheidenden prozeßsteuernden Materialfaktor bei der physikalischen Verwitterung darstellt.

ABSTRACT: On 24 natural building stones weathering forms were described as well as petrographical and rock physical studies conducted. This was accomplished with microfabric studies using mercury porosimetry and other comparative methods. Through the obtained results the rocks were classified according to their porosity characteristics. Furthermore, water absorption and evaporation, as well as freeze-thaw simulations and salt weathering tests were conducted on the rock samples and the resulting weathering characteristics were quantitatively registered by means of porosity studies. The presented data show that the open-space structure of the rock can be seen in the physical weathering as the decisive process-controlling material factor.

RÉSUMÉ: Une description de différentes formes d´altération a été faite pour 24 échantillons de roches sédimentaires. On a procédé à des essais pétrographiques et pétrophysiques. La microstructure a été analysée à l´aide de la porosimétrie au mercure. Les roches ont été classifiées en fonction des caractéristiques de la porosité. En plus on a effectué des essais d´absorption et d´évaporation d´eau ainsi que d´altération accélérée pourévaluer la résistance au gel et au sel. L´altération des matériaux a été suivie quantitativement par des essais de porosité. Les essais en question ont montré que la structure de la porosité constitue un facteur décisif du matériaux qui contrôle les processus de l´altération mécanique.

ZUSAMMENFASSUNG: Ziel der vorliegenden Arbeit war es, den Komplex, der unter den Begriffen Frostverwitterung und Gesteinsbeurteilung im Hinblick auf das Frostverwitterungsverhalten von Natursteinen bekannt ist, näher zu untersuchen.
Aus dem vorher Gesagten geht hervor, daß hierbei zwei Interessengebiete ineinandergreifen und sich teilweise überschneiden. Es handelt sich einmal um den Teilbereich der Allgemeinen Geologie, der sich mit den Problemen der physikalischen Verwitterung beschäftigt, zum anderen um Fragestellungen der technischen Materialprüfung, d. h. um eine Verhaltensbeurteilung von Naturbausteinen.
In den Kapiteln 1 bis 5 werden die einen Verwitterungsablauf bedingenden Voraussetzungen diskutiert. Hierbei wird unterschieden zwischen den Einflüssen des Klimas, den Eigenschaften des durch diese Klimagrößen aktivierten Wassers und den eine Rolle spielenden Materialfaktoren. Da bei der experimentellen Bearbeitung der Naturbausteine Salz-Verwitterungsversuche als Vergleichstest zur Frostverwitterung herangezogen wurden, war es nötig, die hierbei auftretenden Fragen ebenfalls zu untersuchen.
Die Kapitel 6 bis 11 beinhalten in erster Linie experimentelle Untersuchungen zur Verwitterung und damit zur Gesteinsbeurteilung. Hierbei wurden als Schwerpunkte das Hohlraumgefüge, das Wasseraufnahme- und Wasserabgabeverhalten, Frostbeständigkeitsprüfungen und Salzverwitterungsversuche der Gesteine bearbeitet.
Die Versuche wurden an 30 verschiedenen Gesteinen durchgeführt, die alle als Bausteine Verwendung finden. Die Vielzahl der gewonnenen Einzelergebnisse gestattet es, generelle Verhaltensweisen der Gesteine zu erkennen und Arbeitsrichtungen aufzuzeigen, die weitere detaillierte Erkenntnisse zu Fragen der Gesteinsverwitterung und Gesteinsbeurteilung liefern.

SUMMARY: The aim of the research work of this publication was to evaluate in detail the complex which is described by the expressions frost weathering and analysis of rocks in regard to their behaviour as natural building stones under conditions of frost weathering.
There are two different fields of interest which overlap and even interfer. The first one is part of the physical geology dealing with the problems of physical weathering and the second one is part of the materials sciences dealing with the properties of natural building stones.
In chapters 1 - 5 the conditions of the procedure of weathering are discussed. The influences of the climate and the characteristics of the water activated by these climate values and the factors of material which play a part are distinguished.
When working with building stones the salt weathering as a comparison to the tests of frost weathering should be considered and therefore it was necessary to study the questions posed.
The chapters 6 -11 contain mainly the experimental tests of weathering and analysis of stones.
As main points the structure of the pores, the behaviour of the stones in respect of water absorption and water emission, the tests of frost resistance and test of salt weathering of rocks were considered.
The tests were executed on 30 different rocks which are all used as building stones.
The multitude of the individual results allows to recognize the general behaviour of rocks under weathering conditions and to point out working methods which supply a better knowledge of stone weathering and analysis of stones.

RÉSUMÉ: Le but de la présente publication était d'élucider le complexe qui est connu sous les désignations de cryoclastie et d'essais de matériaux en vue de leur résistance à la gélification.
Il résulte de ce qui précède qu'il y a deux centres d'intérêt qui s'engrènent et se couvrent partiellement. Il s'agit d'un côté de cette partie de la géologie générale qui s'occupe de l'altération mécanique et d'autre part de certains aspects des essais des matériaux qui permettent de juger les états de réactions des roches naturelles.
Dans les chapitres 1 à 5 on discute les prémices des procès d'altération. On y différencie les influences climatiques, les caractéristiques de l'eau activée par ces facteurs climatiques et les paramètres des matériaux susceptibles d'influencer ces phénomènes.
Lors du traitement expérimental des roches naturelles on a recouru a l'altération provoquée par la cristallisation de sels à partir de saumures pour la comparer à la gélification.
Les problèmes qui se posent à ce sujet sont également examinés.
Les chapitres 6 à 11 contiennent en premier lieu des essais expérimentaux qui concernent l'altération et qui permettent d'évaluer la résistance des roches. On a examiné principalement l'architecture des cavités de la roche, la capacité d'absorber et d'expulser l'eau, la résistance a la gélification et l'altération par suite de cristallisation à partir de saumures.
Ces essais ont été exécutés sur trente types de roches différentes qui toutes servent comme pierres de construction. La multitude des résultats partiels permet de reconnaître des comportements généralisés des roches et d'indiquer des directions de recherches qui devraient fournir des connaissances plus détaillées sur les problèmes de l'altération des roches et des essais de résistance y relatifs.