Use and evaluation of non-destructive testing methods on stone materials in historical buildings: Example of Hz. Süleyman (Kale) Mosque example

Historical structures, which emerged with the need for shelter in the historical process and reached the present day by changing and shaping for different purposes, are the most important elements and transmitters of our cultural and architectural heritage. Historical structures, which connect the past to the present and the present to the future, are elements that enable us to make sense of the knowledge and accumulation of past civilizations today and to leave a legacy to future generations. The preservation of historical structures in their original form for generations has become a problem for humanity. The sustainability of the concept of protection is important in terms of the physical conditions of the structures. Interventions to be made without knowing the current condition and level of damage to the structure do not provide a sustainable concept of protection. As a result of inappropriate interventions, existing damages progress, and the survival time of historical structures is shortened. It is not possible for structures to remain unchanged in the changing environment. Many structural problems arise when historical structures are exposed to the adverse conditions of the external environment and human effects. The length of the physical life of the structures depends on the level of damage to the structure and its components. Structural problems and damage are a process consisting of physical, chemical or biological deteriorations that cause the structure's strength to decrease and its material properties to change. Determining the problems is an important step in transferring the structures to the future. Today, many methods are applied in damage analysis and intervention decisions. These methods are divided into destructive, semi-destructive and Non-destructive test methods performed on-site or in the laboratory. Non-destructive test methods are used to obtain information about the structure, properties and current damage level of the structure without causing damage to the features required for the use of the historical structure or building material, that is, without disrupting its structure, function and function. Civilizations with different beliefs and cultures have dominated the Suriçi Region surrounded by the historical walls of Diyarbakır. Diyarbakır has been one of the important cities representing Islamic culture and structures belonging to religious architecture have taken shape in the Suriçi Region. Hz. Süleyman (Kale) Mosque, which is among these structures, is located between the bastions of the Inner Castle walls in the Suriçi Region and is accepted as the first settlement area of the city. The mosque has undergone many repairs throughout the historical process and has been expanded with additions and has become a building complex. One of the examples of religious architecture in the city, Hz. Süleyman (Kale) Mosque, damages and problems have developed because of the external environment and intense human circulation. It has been determined that the problems developing because of humidity are observed throughout the structure. In this study, it is aimed to know the superior features of Non-destructive tests, to recognize the methods and to find more application areas in historical structures by including the test methods that can be applied to stone material. In the field study, crack formation, abrasion, separation, joint discharge, salinization and surface pollution problems were determined with the observational analyzes in Hz. Süleyman (Kale) Mosque and in this direction, some Non-destructive tests were applied on the structure and basalt stone. Hardness test with Schmidt hammer, surface smoothness and moisture status determination test, ultrasound transmission speed test, Georadar (GPR) scanning are among the Non-destructive tests performed in the field. As a result of the tests, different hard values of basalt stone were obtained. The highest value was reached in the ground stone and stone columns in the courtyard. It was determined that the moisture rate penetrating the stone was higher in interior spaces. Georadar (GPR) scanning performed on the ground by expert geophysical engineers displayed anomalies that could have a different flooring underground. In the laboratory environment, SEM/EDS analysis was performed on basalt stone and mortar samples. The test findings are presented in tables and graphics. It is aimed that the obtained findings can be used in academic studies, create a roadmap for intervention decisions to be taken later and reveal the importance of preserving architectural identity.