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Trifunovic P.D.,University of Belgrade | Marinkovic S.R.,University of Belgrade | Tokalic R.D.,University of Belgrade | Matijasevic S.D.,Institute for the Technology of Nuclear and Other Raw Materials
Thermochimica Acta | Year: 2010

The content of unburned carbon is an important characteristic of bottom ash which could make it unsuitable for incorporation as aggregate for road construction. In this work, the effect of the content of unburned carbon in the bottom ash from the Serbian power plant "Nicola Tesla" on its applicability for road construction was examined. Four samples with different contents of unburned carbon, i.e., raw bottom ash, two size fractions obtained from it (2-5 and <2 mm) and bottom ash treated by the "float-sink" method, were investigated. When these materials were used as a component in the mixture: fly ash-Portland cement-bottom ash-water for road construction, it was found that only mixtures containing bottom ash with a lower carbon content (size fraction <2 mm and treated) were employable. The content of unburned carbon in the mentioned materials was determined by simultaneous DTA/TGA. This method was also used to investigate the composition of the hardened mixtures. © 2009 Elsevier B.V. All rights reserved. Source

Tokalic R.,University of Belgrade | Marinkovic S.,University of Belgrade | Trifunovic P.,University of Belgrade | Devic G.,IHTM Njegoseva | Zildzovic S.,Institute for the Technology of Nuclear and Other Raw Materials
Journal of Chemistry | Year: 2013

This paper describes an investigation into the use of three power plant wastes: fly ash, flue gas desulphurization gypsum, and bottom ash for subbase layers in road construction. Two kinds of mixtures of these wastes with Portland cement and water were made: first with fly ash consisting of coarser particles (<1.651 mm) and second with fly ash consisting of smaller particles (<0.42 mm). The mass ratio of fly ash-Portland cement-flue gas desulphurization gypsum-bottom ash was the same (3: 1: 1: 5) in both mixtures. For both mixtures, the compressive strength, the mineralogical composition, and the leaching characteristics were determined at different times, 7 and 28 days, after preparation. The obtained results showed that both mixtures could find a potential use for subbase layers in road construction. © 2013 R. Tokalic et al. Source

Smiljanic S.V.,University of Belgrade | Grujic S.R.,University of Belgrade | Tosic M.B.,Institute for the Technology of Nuclear and Other Raw Materials | Zivanovic V.D.,Institute for the Technology of Nuclear and Other Raw Materials | And 3 more authors.
Ceramics International | Year: 2014

Glasses with a constant B2O3 and an increasing La2O3 content in the system La2O 3-SrO-B2O3 were obtained by the usual melt quenching procedure. The crystallization and sinterability of the glasses were investigated by hot stage microscopy (HSM), differential thermal analysis (DTA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). XRD analysis of the bulk samples evidenced the formation of the crystalline phases: La2SrB10O 19, SrB6O10 and SrLaBO4. XRD and TEM/SAED analyses showed a polymorphic crystallization of the glass sample containing 14.3 mol% La2O3 with precipitation of the La2SrB10O19 phase. SEM analysis confirmed the surface crystallization mechanism of this sample. The kinetics of crystallization of the same sample was examined by DTA and the activation energy of crystal growth was calculated by the Kissinger model to be E a=458±63 kJ mol-1. © 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Source

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