A preliminary study for the characterization of Kültepe's adobe soils with the purpose of providing data for conservation and archaeology

Kültepe (Kayseri) became an important trade and cultural center between Anatolia, Northern Syria and Mesopotamia starting with the end of the third millennium B.C. Kültepe structures, consisting of mud-brick walls on stone foundations and wood pillars to carry the roof, formed the basis of the typical Hittite architecture. The area excavated in Kültepe so far is only a part of this grand settlement; however, it is quite a large area compared to many other sites covered by protective constructions. So, it is very important to develop active conservation methods for Kültepe's unsheltered adobe ruins that are under thread of erosion. In this study, a laboratory characterization was made for future experimental preservation studies, in which the physical, mineralogical and chemical properties of the in situ soil remains from a collapsed structure in Kültepe were measured. Initially, color classification, grain specific gravity and specific surface area were identified. Grain size distribution, consistency limits, volumetric and linear shrinkage ratios of the material were determined by mechanical analyses, and the soil was classified based on its granulometry and plasticity characteristics. Clay minerals were identified by X-ray diffraction (XRD) and scanning electron microscope (SEM-EDS) analyses, and sand grains were studied under binocular microscope and polarization microscope for mineralogical analyses. As for the chemicals analyses, soil pH was measured, soluble salt content was examined by simple spot tests and conductivity measurements, and organic matter, calcium carbonate contents were approximately determined according to weight loss on ignition.