WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 9Citation - Scopus: 11Evaluation of Diatomite Substitute With Thermal Power Plant Waste Fly Ash in Sustainable Geopolymer Through Life Cycle Assessment(Springer, 2025-02-28) Ilkentapar, Serhan; Orklemez, Ezgi; Durak, Ugur; Gulcimen, Sedat; Bayram, Savas; Uzal, Nigmet; Atis, Cengiz DuranThis research demonstrates the potential of diatomite as a fly ash replacement to improve mechanical properties and environmental sustainability and presents it as a viable alternative for sustainable construction. Additionally, a life cycle assessment (LCA) was conducted on the produced mortars to quantitatively compare their environmental impacts using a cradle-to-gate approach. In mixtures, it was used by replacing the diatomite in the ratios of 1%, 2%, 3%, 4%, and 5% by weight of the fly ash. Workability, unit weight, flexural and compressive strength, abrasion resistance, elevated temperature resistance and microstructure analysis were carried out. The results indicated that replacing 1%, 2%, and 3% diatomite increased the compressive and flexural strength of mortars due to their higher specific surface area. Two percent replacement of diatomite provided the best results. FESEM results of 3% diatomite inclusion showed more intense and compact microstructure of geopolymer. Diatomite inclusion increased the abrasion resistance of geopolymer. Since 2% diatomite replacement was found to be optimum, the LCA results showed that geopolymer mortar with 2% diatomite has 25% lower impacts in terms of global warming potential and 10% lower impacts in terms of terrestrial ecotoxicity than conventional Portland cement mortar.Article Citation - WoS: 32Citation - Scopus: 35A New Parameter Influencing the Reaction Kinetics and Properties of Fly Ash Based Geopolymers: A Pre-Rest Period Before Heat Curing(Elsevier, 2021-03) Durak, Ugur; Ilkentapar, Serhan; Karahan, Okan; Uzal, Burak; Atis, Cengiz DuranIn this study, the influence of a pre-rest period before heat curing (as a new parameter), on the physical properties, flexural and compressive strength, and microstructure of geopolymer mortars and pastes produced with alkali activation of fly ash were investigated. In this context, geopolymer mortar and paste samples were prepared and pre-rested under laboratory conditions for 0, 1, 2, 3, 7, 14, and 28 days before heat curing. After the pre-rest period, the samples were subjected to heat curing at 75 degrees C in an oven, for 2 days. Mortar and paste samples exposed to a pre-rest period while in the fresh state before heat curing were compared with control samples without pre-resting. Water absorption, porosity, specific gravity, capillarity, flexural strength, compressive strength, and abrasion resistance tests were conducted on the geopolymer mortar samples. A reaction kinetics study using an isothermal calorimeter, XRD, and SEM analyses were performed on the geopolymer paste samples for microstructural investigations. Based on the results obtained, it was observed that the mechanical strength of the samples subjected to the pre-rest period before heat curing increased considerably compared to the reference (without pre-resting) samples. In addition, because of pre-resting, the capillarity coefficient, water permeability, and porosity of the samples decreased compared to the reference samples, and it was concluded that pre-resting improves durability-related properties. Moreover, the reaction kinetics and SEM analysis results, supporting the above findings, showed that a pre-resting period increases the geopolymeric reaction products and causes a denser microstructure.