Monument Future. Siegfried Siegesmund
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Название: Monument Future
Автор: Siegfried Siegesmund
Издательство: Автор
Жанр: Документальная литература
isbn: 9783963114229
isbn:
Based on the coefficient ranges suggested by Hirschwald (1908), the questioned samples can be classified as frost resistant.
The effect of strength reduction of stone material owing to the presence of water is a well-known fact. The effect of water saturation on rock strength has been evaluated to define the wet-to-dry strength ratio. The wet-to-dry strength ratio is also a durability parameter, defined as the ratio between the strength of rock material in wet and dry conditions. Winkler (1986) recommended that the ratio between wet and dry strength values is a rapid and reliable method for classifying rock material in terms of durability. In order to evaluate the wet-to-dry strength ratios of the Midyat limestones, the averages of the saturated and dry uniaxial compressive strength values were used. The wet-to-dry strength ratio of the examined samples was determined to be 0.61. According to Winkler (1986), the expected performance of the questioned limestones were classified as “very poor” and “poor” reflecting less durability.
Thermal properties of the natural buildng stones are important parameters since they have an influence on building climate. Especially it becomes critical while some parts of the building stones are directly exposed to solar radiation (Hall 2011). It is reported that minerals having low thermal conductivity values transmit the heat very slowly from the surface to the inner part of the stone materials (Siegesmund and Dürrast 2011). To measure the thermal properties of Midyat limestones 10 cubic samples were used. The results of the thermal properties are also tabulated in Table 1. it is found that the Midyat limestones have thermal conductivity results ranging from 1.22 to 1.93 W/mK with an average of 1.47 W/mK, and volumetric heat capacity ranging between 1.46 and 1.96 J/m3K, with an average of 1.62 J/m3K.
Figure 2: Some of the deterioration forms observed on Mardin Limestone (a,b) mechanical damages on different sections of the walls; (c) flaking; (d) alveolization at a upper section walls of Dara Ruins; (d) deposits-staining on a gate; (e) efflorescences on the upper left part of an arch; (g) pigeon droppings at the lower section of the wall; (h) salt crust-crumbling at the lower part of a wall.
Table 1: Material properties of the limestone samples based on the laboratory studies.
Conclusions
Regarding its rich cultural, social and religious diversity, Mardin is an extraordinary example of an architectural ensemble. The weathering forms developed on monuments and the physico-mechanical properties of the limestone material have been discussed in the present study. The field surveys indicate that there are numerous weathering forms of various sizes, including efflorescence, alveolization, erosion, deposits and biological colonization, pigeon droppings on the monuments, which are evidence of the destruction and deterioration in progress. The physico-mechanical properties demonstrate that the questioned limestone samples have very high porosity, very low unit weight and weak compression strength. The durability of the material assessed by saturation coefficient and wet-to-dry strength ratio. It can be inferred from the assessment that, all the limestone samples have saturation coefficients of less than 0.8, which means the samples should not be susceptible to frost damage; however, this coefficient alone is not a reliable guide for evaluating the frost susceptibility and durability of rock material. On the other hand, the wet-to-dry strength ratio, limestone samples reflecting less durability. Considering the field observations, these results can be reliable for freshly quarried limestones. Further non-destructive investigations should be performed on the monuments and the results should be correlated with the fresh ones.
Acknowledgement
The author wishes to thank the Dicle University/Scientific Research Project Coordination Office (DÜBAP), for the financial support under the grant number MÜHENDİSLİK.18.007.
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