Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Harnessing Raw Materials in Cement Plants for the Production of Limestone Calcined Clay Cement(Taylor & Francis Ltd, 2026-04-06) Atasever, Muhammet; Erdogan, Sinan TurhanReliance on kaolinite clay in limestone calcined clay cement (LC3) can create availability issues. This study compared a kaolinitic clay obtained from an industrial pit with four other clays used as sources of silica in cement plants, exploring their potential for LC3 production. Three cements were prepared; gray, white, and a composite cement with slag, to investigate the interaction and synergy between the clinker and clay in LC3. Inert quartz was used to replace the clay, limestone, or both components of the mixtures, to evaluate their separate and combined effects on strength, mineralogy, and heat evolution. Several of the LC3 mortars made with the non-kaolinite clays had higher 1-7 d strengths, by up to 60 %, than the LC3 with gray cement and kaolinite which reached similar to 48 MPa strength at 28 d). Carboaluminate formation depends on clinker type, while its quantity is influenced more by the type of calcined clay.Conference Object Citation - Scopus: 1On the Variation in Several Rock Properties due to Magnesium Sulfate Weathering Tests ‒ A Case Study for Limestones(International Multidisciplinary Scientific Geoconference, 2019-06-20) Köken, E.Contributions to the behavior of rock materials under various conditions provide a practical knowledge about issues relating the performance and long-term serviceability of rocks. In this study, various limestones with varying textural features were investigated in terms of their resistance against magnesium sulfate weathering tests. For this purpose, initial physico-mechanical properties of limestones were determined. Then, rock materials were subjected to magnesium sulfate weathering tests (up to 20 cycles) and the variation in physico-mechanical properties were determined for each rock type. As a result of laboratory tests, compared to initial rock properties, effective porosity (ne, %) increased in the range of 3% ‒ 14% and 12% ‒ 35% after 10th and 20th magnesium sulfate weathering cycles, respectively. Uniaxial compressive strength of rocks (UCS, MPa) decreased by 9% ‒ 24% after 10th cycles and by 32% – 58% after 20th cycles. Brazilian tensile strength of rocks (BTS, MPa) decreased in the range of 7% ‒ 19% and 20% ‒ 49% after 10th and 20th cycles, respectively. Similar to the variations in UCS and BTS, Tangential Young Modulus (Eti, GPa) also decreased at a rate of 13% ‒ 28% and 23% ‒ 64% after 10th and 20th cycles, respectively. However, the values of Tangential Poisson’s Ratio (vti) fluctuated with progressive accelerated weathering cycles, which could be linked to varying axial and lateral strain rates at 50% of UCS values for the limestones investigated. Furthermore, the variation in crack initiation stress σCI (MPa) due to progressive magnesium sulfate tests were also evaluated considering two strain-based methods and the findings showed that σCI of limestones slowly decreased with increasing weathering test cycles. It could be claimed that cyclic magnesium sulfate tests performed on rock materials would be beneficial for assessing the long-term serviceability of rocks. In this context, mud-supported limestones seem to have a greater resistance against magnesium sulfate weathering tests compared to the grain-supported ones. However, the number of samples should be increased in order to achieve a comprehensive understanding about the degradation processes of limestones. © 2021 Elsevier B.V., All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Characterization of Limestone Calcined Clay Cement Made With Calcium Sulfoaluminate Clinker(Springer int Publ Ag, 2024-07-02) Atasever, Muhammet; Erdogan, Sinan TurhanThis study concentrated on producing limestone calcined clay calcium sulfoaluminate cement by replacing portland cement in limestone calcined clay cement with calcium sulfoaluminate cement, with the goal of increasing the early strength of limestone calcined clay cement. The mineralogy and microstructures of hydrating pastes were investigated using x-ray diffraction and scanning electron microscopy. Heat evolution was studied using isothermal calorimetry. Strength development and workability were assessed on mortar samples. The 1 day strengths of limestone calcined clay calcium sulfoaluminate cement samples exceeded those of limestone calcined clay cement by similar to 30-80%, though its strength gain slows significantly after 1 day due to the lack of calcium silicates, affecting pH and clay dissolution. Despite this, the strength development of limestone calcined clay calcium sulfoaluminate cement, when adjusted for CO2 emissions, is comparable to limestone calcined clay cement. Additionally, limestone calcined clay calcium sulfoaluminate cement provides a 10-15% higher flow and exhibits a lower heat of hydration beyond 12 h, while maintaining a production cost similar to that of limestone calcined clay cement.