Andreas Rohatsch

A nano-silica consolidant and nano-titania modified tetraethyl-orthosilicate were applied on two building stones, a carbonate and a silicate, by brush, poultice or capillary absorption. Neutron radiography was used to monitor capillary water absorption, and to analyse changes in physical properties caused by heat treatment of specimens for the purposes of artificially ageing and different treatment applications with stone consolidants. Moreover, ultrasonic pulse velocity and gravimetrically determined water absorption were analysed to cross-validate neutron radiography. The results reveal that reactive systems like tetraethyl-orthosilicates need an unknown period for polymerisation, which makes nano-silica consolidants more favourable for construction follow-up work. While polymerisation is incomplete, hydrophobic behaviour, water trapping and pore clogging are evident. Within the tetraethyl-orthosilicate treatment, poultice and brushing are strongly influenced by the applicant, which results in wide ranging amounts of water absorbed and anomalous water distributions and kinetics. The carbonate lithotype displays polymerisation initiated in the core of the specimen, while the lateral surfaces are still mostly hydrophobic. Reaction time differences can be attributed to the different amounts of consolidants applied, which is a result of the chosen application settings. Artificial ageing of stone specimens is a prerequisite when mechanical strength gain is studied, as demonstrated by sound speed propagation.

This paper focuses on a series of ageing tests performed in the frame of a wider study on
the use of innovative consolidants for various architectural stone types. The tested
lithotypes can generally be broken down into two categories: silicate (quartz sandstone with
a clayey matrix) and carbonate (porous detrital limestone and marble). The predominant
deterioration phenomenon of all these stones on-site is loss of grain cohesion and the
formation of micro cracks. Thus, the emphasis lies on reproducing this key-deterioration
effect in every lithotype. An additional effect to be studied for porous limestone is the
formation of a gradient of compactness within the specimen, mimicking a crust on loose
substratum. The ageing progress was evaluated by the methods of determining changes in
ultrasound velocity and water absorption coefficient by capillarity. At critical stages the
micro defects created are analysed by polarizing light and scanning electron microscopy on
petrographic thin sections and mercury intrusion porosimetry. The methodologies for
artificial ageing are as following: 1.) The samples were treated thermally by temperatures
up to 600°C to induce various types of decay; 2.) All samples were additionally subjected
to acid attack, freeze-thaw cycles and salt crystallization alone or in combination with
thermal treatment. The approach of matching the ageing procedure for each lithotype to its
predominant sensitivity and methods used to assess the effect of the ageing treatments are
discussed in terms of relevance to the natural decay phenomena found in exterior
environments of buildings. Thermal treatment proves to be a cost and time efficient method
for assessing artificial ageing for testing of stone consolidants.

The interdisciplinary project Stone Monuments and Stone Quarrying in the Carnuntum – Vindobona Area aims to acquire new knowledge about Roman economic and settlement history, art, quarrying and infrastructure through the analysis of archaeological and geological data collections. Based on macroscopic examination of Roman stone objects as well as the analysis of historical maps and airborne laser scans, potential quarrying regions were selected and samples taken.
The main quarrying areas were located near Perchtoldsdorf (Lower Austria) and in Vienna. It seems that after the installation of the Roman legionary garrison, the building material was quarried from the eastern margin of the Eastern Alps, including the Vindobona vicinity. Additionally, it was possible to prove the origin of Neogene algal limestones from the Leitha Mountains, which played an important role in sculptured stone monuments.
All investigated lithotypes from the mentioned regions belong to the Austrian stratigraphic stages from Neogene sedimentary rock formations of the Central Paratethys.

Orders can currently be placed via email to verlagbeier@online.de.

Bestellungen sind zurzeit über E-Mail an verlagbeier@online.de möglich.

Chapter 20: Abstracts

Stadler Peter, Kotova Nadezhda

In Chapter 1 the new results of magnetic prospection are shown. Including all excavations and former prospection, we now have 125 – 135 houses constructed from about 5650 to 5050 BC. If we take all into account, there might be up to 150 houses, thus making Brunn am Gebirge Wolfholz by far the largest settlement of the LPC, beginning in the Formative phase.

Chapter 2 presents the triangulation map and aerial photos of site 3. Aerial photos were taken on a flight with a helicopter in the excavation year 1999.

In Chapter 3 Alexander Minnich presents statistics of all newly detected hearths and ovens, in which he interpreted the houses in the triangulation map with the exception of those already discussed in volume 1, mostly from site 2.

Chapter 4 investigates technological aspects and the shape of pottery from site 3.

In Chapter 5 the ornamentation of pottery from Brunn site 3 is shown and cast into a typology.

Chapter 6 shows the clay objects, which are amulets and bells, with their parallels in eastern Europe.

In Chapter 7 Beate Pomberger discusses further musical instruments from Brunn – vessel flutes and bells made from ceramics and their parallels in eastern Europe.

In Chapter 8 similarities between the features of the Formative phase of Brunn site 2 are compared with Brunn site 3.

Chapter 9 is the Bayesian approach to a house sequence, for about 27 houses. Only in these houses enough information – radiocarbon dates and ceramics – was available. The same radiocarbon data used in this way can be used for a sequencing of the phases.

In Chapter 10 is given the chronology of the Brunn Sites in the context of the Linear Pottery Culture.

In Chapter 11 Nadezhda Kotova tries to give a sequence of houses from site 3, by using different parameters, such as topography, orientation, climate, seriation, and radiocarbon data.

In Chapter 12 we give an overview of rock materials found at all sites of Brunn Wolfholz.

In Chapter 13 we present a typology of the macrolithic artefacts.

In Chapter 14 a complete dataset of macrolithic artefacts from Brunn Wolfholz is shown.

In Chapter 15 we present a stray find of a stone axe from a geological inspection.

Chapter 16 deals with the further investigation of petrographic and mineralogical analyses of additional selected pottery from the excavation Brunn am Gebirge (locality Wolfholz) from sites 1, 3 and 4 and a comparison with some reference samples.

Chapter 17 disproves our hope to identify Hungarian sites, from where we thought some imported ceramics of Brunn came from.

In Chapter 18 our student Yanik Hahnekamp investigates the topographical situation of LPC
Cemeteries and settlement burials in comparison with the distribution of Mesolithic and LPC settlements.