Identification and evaluation of parameters determined by freezing thawing tests for natural stones

This thesis was carried out to reveal the physical and mechanical behavior of natural stones against weathering due to freeze-thaw cycles and to investigate the changes in the obtained physical and mechanical properties. In this context, samples were obtained from 46 different locations of Turkey. Mineralogical and petrographic analyzes of all sample groups were performed and then their basic physical and mechanical properties were determined. All sample groups were then subjected to 4, 7, 10, 14, 20, 28, 35, 56, 70 and 84 freezing and thawing cycles. After each freezing and thawing cycle, the data of the physical and mechanical properties of the samples were evaluated. The variation of physical and mechanical values with the number of freeze-thaw cycles was presented graphically by considering the average values of all samples and evaluated statistically. With increasing freeze-thaw cycles, it was determined that there were significant decreases in uniaxial compressive strength, Leeb hardness value, P-wave velocity parameters, and increases in apparent porosity, water absorption by weight and wide wheel abrasion parameters. The changes in the monitored values were clearly observed until the 35th cycle, and after this cycle, they were observed at lesser rates. The changes in the physical and mechanical properties of natural stone sample groups after freezing and thawing cycles were evaluated in line with the relevant standards and according to the classifications commonly used in the literature. In addition, uniaxial compressive strength values of natural stones were evaluated within the scope of frost resistance index. The value obtained by proportioning the uniaxial compressive strength of the samples determined after freezing and thawing to the value before freezing and thawing was defined as the frost resistance index. A general freeze-thaw classification system for natural stones using the frost resistance index parameter has been proposed within the scope of the thesis and brought to the literature. In this classification system, rocks are divided into 'very high', 'high', 'moderate', 'low' and 'very low' classes according to their strength after freeze-thaw cycles.