The investigation of the engineering geology and their usability as a natural building stone of limestones from Hani-Diyarbakır

To identify the engineering properties and their use as a natural building stone of Koki limestone located northern east of Diyarbakir and south of Koki village field survey have been carried out in and around three limestone quarries and laboratory experiments have been performed on the samples obtained from the quarries. In the first stage of the study, stratigraphical and structural properties of the limestone beds have been investigated by field works performed in quarry site. In this stage, main engineering properties of discontinuities like locations and orientation, spacing and frequency which affect the block efficiency of stones have been determined by detailed discontinuity measurements carried out on the block production surfaces and as a result, Hani limestone has been classified as a massive rock. Second, mineralogical, physical and mechanical properties of limestones have been investigated with the experiments carried out on rock samples obtained from the rock blocks from the quarries. As a result of microscopic investigations, it has been found that, Hani limestone is a pack stone and its apparent porosity varies between 3.30-3.48 persent and dry unit weight varies between 2.45-2.47 gr/cm3. According to the test results, it has been determined that, uniaxial compressive strength of Hani limestone is 1576 kg/cm2 and its strength decreases while it is loaded parallel to the discontinuity surfaces located in the test samples. As a result of this experiment, it has been determined that, Hani limestone shows anisotropic behavior due to the loading directions in the uniaxial compressive strength test. In the last stage of the study, accelerated weathering tests (wetting-drying, freezing-thawing and salt crystallization) have been performed on the fresh samples to see the behavior of the stone in different prevailing conditions. Additionally, durability of the Hani limestone has been assessed using wet-to-dry uniaxial compressive strength ratio.