Archaeometric Investigation of the Construction Materials of Roman (Caracalla) Bath in Ankara


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Maden Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: ZEYNEP TANRIVERDİ

Danışman: MUSTAFA ÜMİT ATALAY

Özet:

In this study, the characteristics, technologies, provenance, compatibility, durability and deterioration problems of the original materials (stone, stone tessera, brick, mortar, and plaster) used in the construction of the Roman Bath in Ankara are identified through archaeometric methods, such as basic physical and physicomechanical tests (bulk density, effective porosity, water absorption capacity, ultrasonic pulse velocity, hardness tests), and compositional, mineralogical, and chemical analyses (binder aggregate ratio and particle size distribution analyses, gravimetric analysis, salt content tests – spot salt analysis and electrical resistivity – petrographical thin section optical microscopy analysis, Raman analysis, SEM-EDX analysis and, XRF analysis). Firstly, stones are classified into five groups as andesite, limestone, marble, sandstone, and tuff. The provenance of the stones is Hüseyingazi-Kale for andesite, Haymana for limestone, Afyon marble quarry (Antique Marble Quarry) for marble and, Memluk Yuva Village for sandstone and tuff. The durability is low for andesite, sandstone, and tuff while for marble is moderate and for limestone is high. Salination (as phosphate, sulphate and carbonate salts) is the most important deterioration problem for all types of stones. Stone tesserae are in radiaolarite rock group from Elmadağ Irmak Village and low durability. Secondly, the brick work results show that the raw material characteristics and sources of clay in all bricks (structural brick, pilae, and pipe) are the same and local formation. It is the conclusion that the bricks were produced in the same mills, ateliers and in the same period. All original bricks have firing temperature of around 900°C, a porous texture, and a rich composition as to minerals and rock type. However, structural bricks are more durable compared by pilae. The source of the clay material used was found to be METU forest and environs of Cevizlidere for Brick Gr1, Brick Gr2, Brick Gr4, and Brick Gr7, Yenidoğan for Brick Gr3, Brick Gr5, and Brick Gr6, and Tandoğan for Brick Gr8. On the other hand, the aggregates used in the production of the brick materials are basically andesite, granite, and metagrovac, which originate from the local formations of Hüseyingazi Kale, Bala Köprüköy, and southern Ankara, respectively. Besides, all bricks have low durability and the sources of their deterioration are mostly salt, moisture, and biological factors. Thirdly, mortars and plasters composed of traditional 2:1 aggregate:binder ratio have rich, homogeneous particle distribution the majority of which are angular coarse aggregates. The production technology of the structural mortars is of more quality than the pilae mortars. However, the structural mortars in Caldarium (hot room) are more qualified than the ones used in Tepidarium (warm room). While the raw material characteristic, source, and production technologies of the mortars are varied according to in which section of the Bath and for which function they are used, these properties are similar for all original plasters. Thus, the plasters probably were produced in local ateliers and around the same time. Binder material for the mortars and plasters are lime with brick fragments. The lime types of mortar and plaster are cement or natural cement (C/NC) category and highly durable. Finally, the results of garnered for each type of material are evaluated together, and the contributions made by each of the materials to the architecture, construction, and heating and water supply system of the Bath are determined. Aside from this, these findings are reevaluated in terms of social context, revealing new knowledge about the history, archeology, architecture of the Bath, and enabling the reformulation of views on social, cultural, economic, and political life in Roman Period’s Ankara.