Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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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.Article Citation - WoS: 47Citation - Scopus: 52Enhancement of Pozzolanic Activity of Calcined Clays by Limestone Powder Addition(Elsevier Sci Ltd, 2021-05) Argin, G.; Uzal, B.The influence of limestone powder addition on pozzolanic reactivity of calcined clays were investigated. Two clays containing kaolinite and halloysite in their compositions were obtained from different deposits in Turkey and physical, mineralogical, and morphological properties of the raw and calcined clay were characterized. Pozzolanic reactivity of calcined clays with and without limestone powder addition was then examined by means of lime consumption in lime-calcined clay pastes and their isothermal calorimetry as well as strength activity index test. Limestone powder addition enhanced the pozzolanic reactivity of calcined clays by increasing lime consumption and presenting higher heat of reaction released during pozzolanic activity. Limestone addition also provided benefits of reduced water requirement and increased strength activity for calcined clays. Improvements in pozzolanic reactivity and strength activity of calcined clays with limestone powder addition were attributed to nucleation effect provided by limestone particles and also formation of carboaluminate phases during pozzolanic reaction. (C) 2021 Elsevier Ltd. All rights reserved.