Evaluation of limestone quarries for concrete and asphalt production: a case study from Ankara, Turkey

Abstract

Ankara is the capital city of Turkey which is currently flourishing, and there is an increasing need of an aggregate for concrete and asphalt production. The main aggregate requirement of Ankara is provided by the quarry sites named Eski Kibris and Yeni Kibris. The purpose of this study was to determine the chemical, petrographic, and engineering properties of these quarry limestone and to evaluate the determined parameters in concordance with aggregate standards. The uniaxial compressive strength of the samples which are taken from Yeni Kibris and Eski Kibris limestone quarries is in the range between 67.8 and 102.2, and 62.9 and 127.30 MPa, respectively. Yeni Kibris quarry limestone samples are mainly medium-high strength with medium-average modulus ratio and some samples are high strength with medium-average modulus ratio. Eski Kibris limestone samples are medium-low strength rock with a medium-low modulus ratio. Both mine limestone samples are mainly biomicrite. Micro-cracks are filled with large euhedral calcite crystals and iron oxide (in certain samples), which are indicative of a small extent of weathering. The geochemical analysis of samples from the quarry sites of the Eski Kibris and Yeni Kibris shows that the MgO content is less than 1.4%. The total amount of the compounds Fe2O3, Al2O3, SiO2, and MgO is between 1 and 2%. The amount of Fe2O3 is less than or equal to 0.82%, indicating a very low content of clay minerals or iron minerals in the rocks. The Al2O3 content is less than 0.1% and this is meaning that the clay content is less than the desired limit for aggregate quarries. The CaO content is between 55.1 and 55.4%. CaCO3 concentration is greater than 98% in both mines. Chemical contents (MgO, CaO, SiO2, Fe2O3, Al2O3) of both mines are compatible with aggregate standards. Both rock quarries are found to be suitable for aggregate production with respect to the relative density, water absorption, high resistance to freezing and thawing, and abrasion resistance. There are no indications of material which could cause alkali silica reaction at both rock quarries. This study showed that both limestone quarries are suitable for concrete and asphalt production.