『Abstract
　The construction suitability of a dimension stone depends on its weathering properties along with the petrology and the petrophysical properties. The aim of this study was to evaluate the suitability of the dimension stones from the “Drei Gleichen” area for construction and replacement purposes. In total, six sandstones (Ingersleben, Wachsenburg, Hindfelden, Seeberg, Rohnberg（oの頭に¨）, Gleichenberg; Upper Triassic) as well as two carbonates (Wachsenburg sinter; Quaternary, Wandersleben dolomite; Middle Triassic) were analysed. The results from our laboratory and on-site studies of the dimension stones show that rocks from the same stratigraphic layer, like the sandstones from the upper Triassic, can show major differences in their petrophysical and weathering properties. These differences are attributed to their different diagenesis, resulting, e.g. in varying pore space, water balance and strength properties. The pore size distribution can be divided into four different groups based on their occurring maxima and micropore content. The determined water balance properties as well as moisture expansion and salt attack depend on these groups. Next to this, the mineralogical composition significantly influences the weathering resistance. Sandstones with a high content of altered lithoclasts show a high amount of moisture expansion, low strength and, in consequence, a low weathering resistance against salt attack. Based on the results of the present study, an evaluation of construction suitability could be accomplished. From the analysed sandstones, only the Seebergen sandstone is suitable for construction purposes due to its good availability, good strength properties (high compressive and tensile strength, low softening degree) as well as a low porosity. Furthermore, the Wachsenburg sandstone also shows good petrophysical and petrological properties, but exploitable deposits are too sparse to be of commercial interest. From the carbonates, the Wachsenburg sinter shows very suitable rock parameters, but only sparse outcrops occur, which are not appropriate for mining.

Keywords: Dimension stones; Sandstones; Carbonates; Weathering』

Introduction
Geological context and building stones of the Drei Gleichen area
　Deposits and depositional environments of the Drei Gleichen area
The castles of Drei Gleichen - construction history
On-site studies on dimension stones at Castle Gleichen: mapping of lithology and decay phenomena
　Categories of decay
　Mapping of lithology
　Mapping of decay phenomena
Dimension stones: petrology and fabrics
　Lower Keuper
　Middle Keuper
　Schilf sandstone
　Upper Keuper - Rat（aの頭に¨） sandstones
　Quaternary (Holocene)
　Microfabrics of the dimensional stones
Dimension stones: petrophysical properties
　Porosity, density and pore size distribution
　Water transport and retention properties
　Tensile and compressive strength
Laboratory weathering tests
　Thermal dilation
　Moisture expansion
　Salt attack test
Discussion and summary
　Relationship between petrology and pore space properties
　Relationship between pore space, water balance and strength
　Weathering properties
Conclusions - construction suitability
Acknowledgments
Open Access
References