The causes of deterioration of stone materials in the 19th centruy Ottoman Churches of Cappadocia region and the suggestions for their rehabilitation; example of Niğde Küçükköy Church

There are 23 churches belonging to the late Ottoman Empire period in Niğde province, which is located in the south of Cappadocia region. Among these historical monuments, Küçükköy church, which differs from other structures in its architectural plastic decorations and original roof form, has a rare structure among the other monuments in the region. Geological defects, atmospheric and human effects seen in the building stones of this church have accelerated the process of deterioration of the monument. It is important to determine the degree of the deterioration mechanisms in the building stones and to develop appropriate rehabilitation suggestions with minimum intervention in order to hand down this unique cultural asset, which has witnessed a specific period, to the next generations safely. For this purpose, in order to determine the deterioration of the building stones in the monument, systematic experimental studies including laboratory studies (physical, wearing, mechanical, freeze-thaw, determination of mineralogical, petrographical and geochemical characteristics) and in-situ non-destructive tests (material moisture measurement test, infrared thermography, Schmidt hammer resbound, P-wave velocity and portable microscope) were conducted. By comparing the test data obtained from laboratory and site, the degree of deterioration of the building stones was determined. According to the P-wave velocity and Schmidt hammer hardness tests, 187 building blocks are included in the "very weak" and "weak" rock classification. In these building stones, which exhibit low engineering characteristics, there are deterioration in the forms of crumbling, breakage and flaking. In other building stones, deterioration due to spalling and biological effects were determined. Hydraulic lime-bonding plastic repair, integration, drainage and cleaning treatments have been suggested for the control of degradation of building blocks.