Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Production of Waste-Based Lightweight Geopolymer Concretes Using Calcined Bentonite, Fly Ash, Slag, and Expanded Polystyrene Granules(Taylor & Francis Inc, 2026-03-19) Top, Soner; Nussrat Shukur Shukur, Yasir; Vapur, HüseyinThis study investigates the production of environmentally friendly lightweight geopolymer concretes utilizing fly ash (FA) as the primary precursor with calcined calcium bentonite (CCB), ferrochrome slag (SG), and expanded polystyrene (EPS) as supplementary components. A Box-Behnken design was employed to investigate the combined effects of CCB and SG additions, along with the solid-to-liquid ratio, on the compressive strength. Moderate CCB incorporation, particularly around 10%, improved mechanical performance, achieving strengths above 48 MPa, with a maximum of 51.33 MPa at 90 degrees C for a mix containing 5% CCB and 5% SG. Higher CCB dosages (>20%) reduced strength due to matrix dilution, while SG showed limited contribution at elevated levels. Incorporation of EPS granules reduced density to as low as 1292 kg/m & sup3;, yet compressive strengths between 25 and 30 MPa were maintained in mixes with 10% CCB and 0.3% EPS. SEM-EDX analysis confirmed dense geopolymer matrices in FA-CCB composites, whereas SG particles appeared less integrated. These results confirm the potential for producing high-strength, lightweight geopolymer concretes through the effective valorization of waste. The combined use of FA, CCB, SG, and EPS offers a sustainable pathway for resource-efficient construction that supports circular resource utilization.Article Citation - Scopus: 2Zeolite Synthesis by Alkali Fusion Method Using Two Different Fly Ashes Derived From Turkish Thermal Power Plants(Chamber of Mining Engineers of Turkey, 2020-03-01) Top, S.; Vapur, HüseyinIn this study, Faujasite (Na-LSX) (3.5(Ca0.3)3.5(Na0.6)3.5(Mg0.1)Al7Si17O48 32(H2O)) type zeolites and Ca-Filipsite (CaK0.6Na0.4Si5.2Al2.8O16 6(H2O)) type zeolites were produced from Sugözü Thermal Power Plant and Çatalaǧzi Thermal Power Plant fly ashes by alkali fusion method followed by water leaching, respectively. In these methods, fly ashes and sodium hydroxide (NaOH) were mixed in certain proportions and sintered at 600°C in ash furnace. Then, zeolites were obtained from the ground materials after water leaching and solid/liquid separation, respectively. Cation Exchange Capacity (CEC), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Fluorescence (XRF) and Atomic Absorption Spectrometer (AAS) analyses were used to characterize the synthesized zeolites. The zeolites synthesized with Sugözü fly ashes in a ratio of 1:2 had 136.93 meq/100 g CEC, whereas the CEC of synthesized zeolite from Çatalaǧzi fly ashes was found to be 247.88 meq/100 g. As a result, zeolites, which can be used as wastewater treatment agent, energy storage material, catalyst and separator, were synthesized by using 2 different Class F fly ash. © 2023 Elsevier B.V., All rights reserved.Book Part Citation - Scopus: 2Properties of Alkali-Activated Lightweight Concrete(Elsevier, 2022) Top, S.; Altiner, Mahmut; Vapur, HüseyinThis chapter presents a brief overview of the properties of alkali-activated lightweight concrete. Nowadays, the production of lightweight concrete has great attentions due to its extraordinary advantages such as reduced mass, improved sound and thermal insulation properties. Furthermore, the low gas emissions and the utilization of waste materials increase the importance of alkali-activated lightweight concrete. In this chapter, the strengths of lightweight concrete were examined by considering the aggregate type and density, the alkali activator type and concentration, the type of fiber reinforcements and foaming agents, which are the factors that have the most impact on the strengths. Thermal conductivity, fire resistance, acoustic performance, and durability properties have been explained considering the key points in the literature. In addition to porosity, it has been determined that one of the most important factors directly affecting the fire resistance is the precursor type. It has been concluded that the fire resistance of the concrete prepared by using K-based precursors is higher. Acoustic performances of alkali-activated lightweight concrete vary. It is necessary to use a high amount of aggregate in order to obtain concretes with wide frequency ranges and high absorption coefficient. Contrary to concrete produced from Portland cement, alkali-activated concrete is more resistant to acid and sulfate attacks, since the formation of gypsum and strength is less. © 2022 Elsevier B.V., All rights reserved.