Bazı tarihi anıt harç ve sıvalarının incelenmesi
Characterization of mostars and plasters of some historic monuments
Yazar: AHMET GÜLEÇ
Danışman: DOÇ.DR. TÜLAY TULUN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü
Derece: Doktora, 1992
Konu: Kimya = Chemistry ; Mimarlık = Architecture
Dizin: Dolgu maddeleri = Fillers ; Harç = Mortar ; Katkı maddeleri = Additives ; Roma Hamamı = Roman Bath ; Sıva = Stucco ; Tahtakale Hamamı = Tahtakale Bath

Özet:
ÖZET Harç ve sıvalar, bina yapım sırasındaki ve sonraki işlevleriyle, günümüz yapılarında olduğu gibi tarihi anıtların da en önemli elemanlarıdır» Tarihi binaların restorasyon ve konservasyon çalışmaları büyük bir titizlik ve dikkat ister. Restorasyon çalışmalarında uygun oranlarda ve doğru malzeme seçerek hazırlanmayan harç ve sıvalar, eski yapı üzerinde telafisi mümkün olmayan problemler neden olur. Buna engel olmak ve yapıya uyumlu harç ve sıva üretmek için or j inal harç ve sıvaların kimyasal ve fiziksel özelliklerinin bilinmesi zorun ludur. Bu çalışmada, seçilen tarihi yapılardan alınan harç ve sıva örneklerinin kimyasal ve fiziksel özelliklerini aydınlatmak için yas kimya, petrografik, X-ısmları difraksiyonu (XRD), taramalı elektron mikroskopu (SEM), element dağılım analizli X~ısmlar difraksiyonu (EDAX), porozimetri ve yoğunluk analizleri yapılarak sonuçları değerlendirilmiştir.

Abstract:
CHARACTERIZATION OF HORTARS AND PLASTERS OF SOME HISTORIC MONUMENTS SUMMARY Mortars and Plasters are the most important materials of a construction and their functions give information about the living mode of the period of a building» The conservation and restoration of historical monuments require detailed information about the original materials and the materials used in repeairs. It is the fact that a right characterisation of mortars and plasters from different monuments and periods can be succeded by an interdiciplinary studies which should include chemical, physical, petrographic and minerological examinations of materials. Moreover, there is still the lack of standard methods of analyses for building materials» But» most of the standards, used for the modern costruction materials are not valid for old ones» Unfortunately this is one of the main problem for the characterization of these materials and the discussions are still going on for entirely satisfactory results» The present study is dealing with the identification of mortars and plasters of the Roman Bath (RB) Tahtakale Bath (TB) and Esekapi Madrasah (EKM),to give some preliminary information about the materials of these monuments» MONUMENTS The Roman Bath (RB) is located at Ulus, in Ankara. The first surface research and excavation of the RB had been done by Professor Mahmut Ak ok, between 1940 - 1952 [37], The ruins are from Frigian and Roman ages. There are also very few repairs from Byzantine periods by- strengthening and capping the walls with mortar and plaster» Since then it has been used as an open air museum » Tahtakale bath (TB) is located at Eminönü, in Istanbul. Although is does not have an inscription, it was registered in the Waqfiyya (foundation deed) of Mehmet the Conquerer in 1489 and therefore it should have been erected between 1453-1489 in the Byzantine Harbour Nerion, near the sea walls [38]. It was burnt partially in 1660 and 1688. The fire of 1726 was hazardious for the frigidarium of the men's division and for the caldarium of the ladies division. After the first decade of the 19th century, it has not been used as a bath and converted to a storage house» The original plan of the building was altered due to the new functions. Especially VIthe ladies division has lost part of its walls and domes. The division was not altered and remained well conserved. The domes were one or two bricks thick with respect to the span. The mortar ?found on the domes and tooth-saw.freeze of the drums gives evidence that the original domes were covered with roof tiles C383. Esekapi Madrasah (EKM) is located at Kocamusta-f apasa, in Istanbul. It was registered in the waqfiyya o-f the Ibrahim Pasha who was the Grand Vizier (minister) of Süleyman the Magnif i cant, in 1560 C403. It has been erected after 1560 near the Isa Sate of the land walls. EKM was an old Byzantine church. It was converted to a masque and the madrasah was added by the famous architect Sinan. After the 1894 earthquake C413 the madrasah has not been restored. The porticos, which was present up to 1930, &re completely lost. The classroom and cells are domed while mosque is roofless, at the present state. EXPERIMENTAL PART MATERIALS AND METHODS The sampling of mortars and plasters was carried out from different points in order to show analogous or different characteristics of the materials of monuments at the foundation different levels and sides of walls, different rooms and domes. With these samples a statistical analyses of a monument can be performed and the relationship of the properties of materials and building technology can be established. The number and the size of the samples depend on the monuments. If the monument is in restoration many and quite large samples could be taken, like TB. In the other cases the number and size of the samples are limited, like at EKM and RB. As a result of these circumstances 79 samples from TB, 51 samples from EKM and 19 samples from RB were taken. All samples were listed on plans A. 1-A.5. The methods used in this study can be summarized as in the fallowing orders; WET CHEMISTRY: For about two hundred years some of the methods follewed in chemical analyses of the natural and the artificial materials are still prevalent and the classical scheme of analyses are practically unchanged. Particle size analysis, moisture content, loss of ignition, water and acid disintegration of samples were carried out and the soluble salts contents öf the samples were determined by atomic absorb t i on spectroscopy (Table A. 8). Qualitative Determination of proteins and sponifying oil materials and the anions were carried Vllout with the given methods (Table A.7). The calcimetry analyses of the samples were carried out as fol lows ; About 500 mg finely ground samples were taken in a porcelains crucible to weight 0.10 mg precission. Then the sample was heated in an oven at 105±5 °C, 500±5 °C and 1050+5 °C for 2, 1 and 0.5 hours respectively. After each heating the samples were cooled in a desiccator and weighed. From the weight differences, percent of moisture absorption (MAC), ignition loss at 500° C (I'D and carbonate content ( CC ) were calculated as below? where W is weight of sample, Wl is weight of sample after heating at 105±5 °C, W2 is weight of sample after heating at 500+5 °C and W3 is weight of sample after heating at 1050±5 °C. The results of calcination analyses were given in tables A.4-A.6 and figures A.11-A.16. PETRQGRAPHIC ANALYSES s Thin section analyses of the samples were done for the identification of minerals in order to evaluate analogous or different properties. The photograps are showing in figures A.17-A.30. X-RAY DIFFRACTION (XRD) ANALYSES 5 The minerological composition of the samples were determined by XRD analyses by using CuKa radiation. XRD diagrams of samples are given in figures A.31-A.42. SCANNING ELECTRON MICROSCOPE (SEM) ANALYSES t Tex tura 1 properties of samples and the nature of minerals in them are examined by SEM analyses. Results are shown in figures A.52-A.90. ELEMENTAL DISPERSIVE X-RAY DIFFRACTION (EDAX) ANALYSES s EDAX analyses are evaluated with SEM data. The element contents of the certain points of samples are determined semiquantitatively by EDAX and the diagrams are shown in figures A.52-A.90. PHYSICAL ANALYSES s The density and the porosity measurments of samples are done and the results are given in table (tablo A. 14). RESULTS AND DISCUSSION The mortar samples of TB and EKM composed of uniformly distributed binder, fine and coarse aggregates of various colours and textures. Crushed and partly Vlllground bricks were mostly used as aggregates and artificial pouzzolanic materials. The colour of them were varying from red to whitish cream. A few of the mortar samples contained short cut tows as organic material. There were two layers of plasters. The inner (undercoat) layer was similar with the mortars, in composition, colour and texture. This layer contained more lime than some of the mortar samples. The colour of the outer (finishing) layer was whitish cream. This layer- was rather thin and consisted of very large quantity of lime (around 80 %) and very fine aggregates of ground stones. Most of the plaster samples contained large amound short cut tows. The mortar samples of RB, except a few ones, showed very different characteristics from those TB and EKM mortar samples. They mostly composed of randomly distributed limeless binder, fine and coarse, pebble like aggregates in various textures, which showed modern mortar characteristics. The colour of them changed from dark grey to light grey. The plaster samples of RB showed almost the same composition, colour and texture as the mortar samples. Just a few samples, which were taken deeper than the others, had analogy with TB and EKM samples. The results of visual and calcination analyses clearly showed that most of the mortar samples of TB and EKM were lime mortars which were supported by crushed and ground bricks as artificial pouzzolanic materials. These kind of mortars were generally called "Khorasany mortars" if they were from Seljuk or Ottoman periods, or "Roman mortars" if they were earlier than those periods. The lime content of wall and basement mortars of TB cumulated around 40% in weight (figures A. 11, A. 12). While lime content of the basement mortar samples extended to the 50%, the lime content of wall mortar samples changed between 30% to 50%. The mortar samples, used for construction of domes had 30% lime. These results showe that the binder used for the construction of walls were more or less similar with the foundation construction materials. The lime content of mortar samples of EKM, which were taken from walls, were quite similar with those of the wall mortar samples of TB. Since the foundation of EKM was under ground, no sample has been tested. The different layers of plaster samples showed very different amount of lime contents. Inner pink layers had around 35% and outer white layers had around 80% lime. The lime content of mortar and plaster samples of RB cumulated around 20% and 30%. The plaster samples 7 and IX8 showed larger amound lime than the others. Because, these samples were taken -from the water storage of the bath, where carbonates dissolved in water should have precipitated over the sur-Faces. There-fore the carbonate ?Found in these samples should be the total of the lime and precipitate. Thin section analyses o-f mortar and plaster samples of RB showed that they were quite homogenous with most o-f the mass made up o-f quarts, calcite and very little plagioclase and feldspar. The quartz content was rather- large (figure A. 28). The aggregate content was over 65% and the aggregates were very close to each other (figure A. 29). Quartz and calcite grain sizes ranged from 0.1 mm to several millimeters, and their shapes were angular with low spherical property. Just a few samples of RB had crushed and ground brick pieces (figure A. 30). Thin section analyses of TB and EKIİ mortar- and plaster samples showed very different characteristics from those of RB samples. Mortar samples mostly were made up with crushed brick pieces (figure A. 17) and little amount of quartz, carbonates, calcites (figure A. 18) and very little amount plagioclase (figure A. İ9) and feldspar. The appearance of carbonate and broken shells indicated that these aggregates were prepared by crushing the "Küf eki " stone, which is a kind of cal carious sedimentary local stone. The mortar samples of domes (outside) were different from the wall samples. They did not contain any crushed bricks and stone pieces, but large amounts of (over 65%) pebbles like aggregates (figure A. 20) where their sizes ranged from 0.3 to 3 millimeters. Their (EKM sample numbers 28, 29, 30) moisture absorption capacities &r c ami nations proved that the mortar samples of TB and EKM were basically "Khorosany" mortars with a homogenous matrix, mostly made o-f crushed brick, calcite, quarts and very little amounts of plagioclase and feldspar. The lime was very well ground. The quality of workmanship used seems to be of high order. The mortar and plaster- samples of RB were simple modern cement mortars, which were probably used in previous restorations of the monument. The plasters of TB and EKM were composed of two distinct layers. The inner pink layers were quite similar to the mortar samples, while the outer white layers were finishing coats, composed of lime and a small amount of very fine aggregates. Most of the plaster samples contained tows to increase the strength, and they were in sound a state. The porosity measurements of mortar and plaster- samples of TB and EKM showed analogy and they had higher SPV than RB samples. There were not remarkable amount of soluble salts and no evidence of dolomite. Only the white layer of plasters showed gypsum formation on the exposed surfaces, XXI