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Archaeometrical investigation of some Seljuk plasters

Caner, Evin
The aim of the study was to investigate Seljuk Plasters used in some of their royal administrative or residential buildings from a viewpoint of their raw materials and technological characteristics. Some Byzantine Plasters of the same period were also investigated to make comparison. Plasters from some historic structures in the archaeological sites namely; Alanya Castle, Kubadabad Palaces, Syedra Archaeological Site, Aspendos Amphitheatre, Selinus Archaeological Site-Sekerhane Kösk and Hasbahçe were examined. In a series of examination basic physical properties of the plasters as bulk density, porosity, water absorption capacity and water vapour permeability were obtained. The results indicated that plasters are low dense and high porous materials and having good breathing property. Mechanical properties of the plasters were expressed by the modulus of elasticity (Emod) values which were obtained from ultrasonic pulse velocity measurements. The Emod of the plasters being in the range of 1.0 to 5.6 Gpa show that they have enough mechanical strength comparable to historic mortars and bricks. Raw material composition and mineralogical properties of plasters were determined by combined interpretation of several types of analyses such as chemical analyses, particle size distribution of aggregates, petrographic analyses of thin sections by optical microscopy, scanning electron microscopic analyses of cross sections coupled with EDX for image analyses and semiquantitative elemental analyses, X-ray powder diffraction analyses for the determination of mineral phases, thermogravimetric analyses and FTIR analyses. Binder used in all plasters was found to be lime with amount in the range of 53.8-96.8% as CaCO3. The main minerals of aggregates are quartz, calcite (limestone), dolomite and opal-A. Regarding particle size distribution of aggregates it was possible to classify