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Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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Author: search.filters.author.Uzal, BurakHas files: No

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  • Article
    Effects of Alkanolamines on Calcium Sulfoaluminate Belite Cement Hydration and Fresh Properties
    (Emerald Group Publishing Ltd, 2026) Uzal, Burak; Wilkinson, Angus P.; Qoku, Elsa; Nguyen, Tu-Nam; Kurtis, Kimberly E.
    Calcium sulfoaluminate belite cements have found widespread use in specialised applications but have not been applied broadly due to rapid setting times. Conventional set retarders such as citric and tartaric acids modify hydration kinetics, introducing ancillary effects that alkanolamines may avoid. This study examined the effects of three alkanolamines, triisopropanolamine (), triethanolamine () and diisopropanolamine (), on early hydration at 0.02% dosage; was also tested across a broader dosage range. Reaction kinetics and phase evolution were examined in pastes by calorimetry, thermogravimetric analysis () and in situ quantitative X-ray diffraction () for 72 h of hydration, along with setting time and amplitude-sweep rheometry. Calorimetry showed that and delayed and reduced the main cement hydration peak, while all alkanolamines delayed and enhanced the shoulder and secondary hydration peaks. In situ and suggested that alkanolamines decrease ettringite and alumina gel formation by 24 h and may lead to poorly crystallised ettringite that cannot be quantified by . Alkanolamine-containing samples demonstrated increased storage and loss moduli and extended linear viscoelastic ranges. A consistent grouping of similar behaviour emerged: control/TIPA versus TEA/DIPA, suggesting distinct mechanisms. Finally, among the alkanolamines, was the most effective, increasing the setting time by 18 min.
  • Book Part
    Citation - Scopus: 1
    Energy Simulation Optimization for Building Insulation Materials
    (Springer International Publishing, 2023) Himmetoğlu, Salih; Delice, Yılmaz; Kızılkaya Aydoğan, Emel Kizilkaya; Uzal, Burak; Aydoğan, Emel Kızılkaya
    Recently increased energy consumption and carbon emissions caused by energy consumption have mobilized governments. Energy-efficient building designs have become one of the most fundamental strategies preferred by governments. The heating and cooling demands have an important share in energy consumption in buildings. Therefore, thermal insulation systems have become the basic building elements to design energy-efficient buildings. Determining suitable thermal insulation strategies for energy-efficient structures built in different climates is an important decision problem for designers. This study aims to select insulation material and insulation thickness for energy-efficient building design. The stone wool, extruded polystyrene (XPS) insulation materials, and their alternative thicknesses are considered for Turkey’s two different climate zones. The Energy Plus and Design Builder energy simulation programs are used to analyze all alternatives. A decision support system is generated by considering both the material cost and the heating and cooling energies to be consumed during the building life cycle. The most suitable insulation material for the first zone is stone wool, and its thickness is 10 cm. The most suitable insulation material for the second zone is stone wool, and its thickness is 10 cm. The total saving is 11% for the building in the first zone. The total saving is 9% for the building in the second zone. The generated designs have been quite stimulating for decision-makers. © 2024 Elsevier B.V., All rights reserved.
  • Article
    Citation - WoS: 1
    Effect of Mineralogical Composition of Clinoptilolite-Bearing Tuffs on Their Performance as a Natural Pozzolan in Cementitious Systems
    (Techno-press, 2021) Ozen, Sevgi; Uzal, Burak
    In this study, pozzolanic reactivity and strength activity of zeolitic tuffs containing similar amount of zeolitic phase (clinoptilolite) and different types and amounts of impurities were examined in order to understand the role of mineralogical composition in the efficiency of zeolitic natural pozzolans. Mineralogical and chemical compositions as well as the physical properties of the zeolitic tuffs were determined. Their pozzolanic reactivity were measured as depletion of calcium hydroxide in the pastes containing lime and zeolitic tuff, which is determined by thermogravimetric analysis. Furthermore, compressive strength of blended cement mortars prepared with 20% replacement of Portland cement by finely ground tuffs were determined at 7, 28 and 56 days of age. It was demonstrated that the type and amount of impurities in mineralogical composition of zeolitic tuffs are significantly effective on their early pozzolanic reactivity. Zeolite mineral content, however, is more determinative on long term reactivity. For a strength activity, mineralogical composition was clearly effective on the preparation of mortar samples, which depends on water requirement of zeolitic tuffs.
  • Article
    Compatibility of Superplasticizers With Natural Pozzolan Blended Cement: Multi-Criteria Compatibility Index Through Rheology and Hydration Kinetics
    (Taylor & Francis Ltd, 2025-08-09) Argin, Gizem; Uzal, Burak
    An effective technique to decrease carbon dioxide emissions in the cement industry is the partial replacement of clinker with supplemental cementitious materials (SCMs). Given the restricted supply of by-product SCMs such fly ash, blast furnace slag, and silica fume, natural pozzolans provide viable options in the manufacturing of blended cement. In cementitious systems with natural pozzolans, the use of superplasticizers is essential to compensate for the reduced workability caused by their higher water demand. This study investigates the compatibility of different superplasticizer types, administered at similar dosages, with Portland cement containing 40% natural pozzolan, focusing on paste rheology and hydration kinetics. A Multi-Criteria Compatibility Index (MCCI) was created to provide a comprehensive and quantitative evaluation of compatibility between natural pozzolans and different types of superplasticizers, utilizing rheological and hydration kinetics within a weighted scoring framework. The assessment findings indicated that PMS displayed the best overall compatibility, principally owing to its improved hydration properties, but PNS revealed enhanced performance in rheological characteristics. PCA demonstrated restricted compatibility in both categories. The MCCI framework delivered a balanced and thorough comparison unattainable by single-parameter studies, providing a solid methodological foundation for future study on SCM-admixture compatibility.