Performance and Risks of Salt-Accumulating Renders in Relation to Their Moisture Transport Properties

Salt-accumulating renders are usually applied in several layers with different specific properties of moisture transport. An extensive experimental programme was carried out to establish a relationship between those properties of individual layers and the performance of combined systems on a salt-laden substrate. Each of the 20 renders was characterized separately in absorption and drying tests, vacuum saturation tests, dry cup tests, mercury intrusion porosimetry, and ultrasound wave velocity measurements. Each of the 12 combined render systems was applied on a brick, which was then saturated with a concentrated NaCl solution by free capillary uptake. Subsequently the assembly was closed at the bottom and subjected to an accelerated drying test (50° C and 15% relative humidity). Moisture and salt profiles over the depth were taken regularly during 1 month. The results reveal very different degrees of effectiveness and levels of risk for the substrate, which are related to the moisture transport properties.     

Contributors' Addresses

The author presents a progress report on his computer‐based research on Hellenistic Greek texts and summarizes practical procedures he developed in the course of his study of the Pseudo‐Philonic De aetemitate mundi. He discusses word‐length as a chronological criterion, the formation of testable hypotheses concerning matters of style, and ways to display a text so as to expose its structure. He seeks to promote the use of quantitative methods in Greek philology and to encourage the use of computers in the study and teaching of Greek but is also at pains to point out limitations inherent in the techniques he advocates.     

Paper 2: Climatic Study of the Underground Archaeological Site Coudenberg

Abstract

The excavation and valorization of subterranean archaeological remains, and eventually opening a site to the public, required a proper management and conservation strategy. This strategy was based on the evaluation of the delicate balance between the requirements for public health and safety, and the protection of the archaeological remains from future degradation. Controlling the climate can be essential for a preventive conservation strategy, which can be defined as an indirect action to increase the life expectancy of the archaeological remains, and by doing so keeping them in a preferred state of conservation to mitigate damage and/or deterioration.

Potential risks and possible interventions are outlined to avoid climatic conditions which are in conflict with the requirements for the visitors’ comfort while preventing damage phenomena to the materials.     

Paper 4: Mechanical Properties of Bricks of the Coudenberg Archaeological Site in View of a Proper Conservation Strategy

Abstract

Archaeological sites are essentially submitted to decay phenomena inherent on their history as well as the environment to which they are exposed after excavation. The history of such archaeological sites is particularly related to their long-term underground conservation conditions during which they were subject to salt migration into the architectural remains. This paper describes the results of drill resistance measurements using a drill resistance measurement (DRMS) device to evaluate the mechanical damage resulting from salt crystallization pressures. Further tetraethoxysilane (TEOS) was applied on powdered bricks of often moist archaeological remains. It was noticed that TEOS serves as potential nutrient for present moulds. The mechanical consolidation effect was evaluated by comparing the hardness profiles after treatment with the reference ones. Bricks used for the construction of the Aula Magna, situated underneath the Royal Square, are characterized by severe patterns of fissures for which the damage diagnosis was built up.     

Paper 5: Historic Mortars from the Coudenberg Archaeological Site: Characterization and Source of Raw Materials

Abstract

The characterization of historic mortars by means of a concise methodology of material analyses can provide crucial information with regard to the origin of the raw materials and the ancient mortar technology. For the analysis of the historic mortars of the Coudenberg archaeological site, the methodology consists of optical and scanning electron microscopy, simultaneous thermal analysis, and an acidic treatment. These analyses were carried out on a total of seventeen samples lifted from various areas in the site, in function of the building chronology resulting from a historic built investigation. The type of binder and aggregate as well as their volumetric ratio were determined.

Both binder and aggregate present distinctive features, which made it possible to identify the probable geological provenance of the raw materials. The observations are verified with available historical records regarding the construction of the main banqueting hall — the Aula Magna — and the use of raw materials such as limestone and sand for the production of lime and construction purposes.     

Claus Bjørn and Carsten Due-Nielsen. Fra Helstat Til Nationalstat 1814-1914. Edited by C. Due-Nielsen,O. Feldbæk and N. Petersen. Vol. 3, Dansk Udenrigspolitiks Historie. (Copenhagen: Gyldendal Leksikon, 2003). 536 pp. ISBN 87-7789-091-4

This article focuses on the bishops in the Church of Sweden as an elite group in society. Using the conceptual apparatus of Pierre Bourdieu, including field, capital and habitus, the article gives a brief background to and describes the social characteristics of this elite group during the first half of the 20th century. It describes the double position of the Bishops as officials both of the state and the Church. In the 20th century, the church lost influence in society and as a consequence so did the Bishops. A discussion is held in the article how the Bishops acted to maintain and legitimate their position as an elite, for example by forming an informal network.     

Paper 6: Grouting Mortars for Fragmented Bricks and Repair Mortars for Tiles in the Archaeological Site Coudenberg

Abstract

Different grouting and repair mortars were developed and evaluated for the conservation and restoration of fragmented bricks in the walls and floors of the remaining cellars underneath the Aula Magna, the palace’s main banqueting hall, and to fill the lacunae and perform edge repairs of red and blue-grey ceramic floor tiles in the remaining cellars underneath the chapel of the former Palace of Coudenberg in Brussels, Belgium.

To prevent the deposition of lime bloom at the surface of the masonry and to achieve an acceptable colour match of the grout in harmony with the bricks of the Aula Magna, the effect of brick powder added to natural hydraulic lime was studied. The pozzolanic properties and colour match of several historic and modern powdered bricks were investigated. Surprisingly, ancient bricks do not seem to possess higher pozzolanic properties than the more modern ones, although it is supposed that they were fired at lower temperatures. Additional evidence for the pozzolanic reaction of the different brick powder materials was obtained from a simple visual observation of stored samples. After eight weeks all of the samples containing brick powders, fired at low and high temperatures, added to putty lime had hardened under water and were transformed into a remarkably tough material. These results are important, as modern bricks are readily available in large quantities and different colours, which are hence in favour of being used instead of historical material from the site.

For the repair of the ceramic floor tiles different mortars were investigated with mixtures containing talcum, stone or brick powder, pigments, and chalk added to an epoxy binder. The mortars were tested in the laboratory and in situ for their workability and resemblance with the historic floor tiles. The finished mortars showed excellent aesthetic properties with the tiles in situ and good properties to prevent further loss due to human interaction.     

Paper 3: Impact of the Indoor Climate on the Performance of Building Materials Contaminated with Salt Mixtures

Abstract

Archaeological sites are essentially submitted to decay phenomena inherent on their history as well as the environment to which they are exposed after excavation. The history of such archaeological sites is particularly related to their long-term underground conservation conditions during which they were subject to salt migration into the architectural remains.

It is well known that soluble salts present in building materials can cause damage, mainly by producing stresses in the substrate. A lot of research has been done in the past concerning the behaviour of salts in built constructions. However, most studies include single salts, of which the deliquescence points are well documented, while in situ one mostly finds complex salt mixtures, which makes the conservation strategy much more intricate.

The environmental conditions to minimize damage of salt-laden porous building materials can be modelled using a computer program ECOS capable of predicting the crystallization behaviour of salt mixtures. To use the model data of quantitative salt analyses are required as input. The program is then able to predict from a thermodynamic point of view which minerals will exist in the solid state under specified climatic conditions.

This paper deals with the results of a systematic investigation of the salt contamination of the building materials of the Coudenberg site and a prediction of the behaviour of the salt mixture related to the actual climate, as part of the environmental assessment.     

From “Spitsbergen” to “Svalbard”. Norwegianization in Norway and in the “Norwegian Sea”, 1820–1925

Abstract

The aim of the paper is to enhance our understanding of the Norwegian acquisition of Spitsbergen/Svalbard by using the concept of Norwegianization as a tool for analyzing the political and diplomatic background for the Spitsbergen treaty of 1920, and comparing the Norwegianization polar politics with the Norwegianization concept used to analyze the internal colonization in the Sami districts of northern Norway during the same period. The paper concludes that the politics of Norwegianization on the main islands in the North Ocean – renamed the Norwegian Sea by Norwegian oceanographers in the 1870s – was an offensive policy of expansionism, motivated by historical and geographical considerations and alleged rights to re-establish the Medieval Norse empire.