Zvezdana Baščarević
University of Belgrade
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Featured researches published by Zvezdana Baščarević.
Journal of Hazardous Materials | 2010
Miroslav Komljenović; Zvezdana Baščarević; V. Bradić
This paper investigates the properties of geopolymer obtained by alkali-activation of fly ash (FA), i.e. the influence of characteristics of the representative group of FA (class F) from Serbia, as well as that of the nature and concentration of various activators on mechanical and microstructural properties of geopolymers. Aqueous solutions of Ca(OH)(2), NaOH, NaOH+Na(2)CO(3), KOH and sodium silicate (water glass) of various concentrations were used as alkali activators. It was established that the nature and concentration of the activator was the most dominant parameter in the alkali-activation process. In respect of physical characteristics of FA, the key parameter was fineness. The geopolymer based on FA with the highest content of fine particles (<43 microm), showed the highest compressive strength in all cases. Regardless of FA characteristics, nature and concentration of the activator, the alkali-activation products were mainly amorphous. The formation of crystalline phases (zeolites) occurred in some cases, depending on the reaction conditions. The highest compressive strength was obtained using sodium silicate. Together with the increase of sodium silicate SiO(2)/Na(2)O mass ratio, the atomic Si/Al ratio in the reaction products was also increased. Under the experimental conditions of this investigation, high strength was directly related to the high Si/Al ratio.
Journal of Hazardous Materials | 2012
Miroslav Komljenović; Zvezdana Baščarević; Nataša Marjanović; Violeta Nikolić
This paper analyses the effects of decalcification in concentrated 6M NH(4)NO(3) solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si ~0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.
Hemijska Industrija | 2006
Zvezdana Baščarević; Miroslav Komljenović; Ljiljana Petrasinovic-Stojkanovic; Natasa Jovanovic; Aleksandra Rosic; Mihailo Rsumovic
In this paper the results of the investigated properties of fly ash from four thermal power plants in Serbia are presented. The physical, chemical, mineralogical and thermal characterization of fly ash was carried out, in order to determine the possibility to utilize this material in the building materials industry, foremost in the cement industry. It was determined that, although there are differences concerning the physical, chemical, and mineralogical characteristics of the investigated samples, they are very similar concerning their thermal characteristics. It was concluded that using fly ash as one of the raw components in the mixture for Portland cement clinker synthesis, not only enables the substitution of natural resources, but it might have a positive effect on the lowering of the sintering temperature.
Ceramics International | 2015
Nataša Marjanović; Miroslav Komljenović; Zvezdana Baščarević; Violeta Nikolić; Rada Petrović
Applied Clay Science | 2015
Anđelka Đukić; Ksenija R. Kumrić; Nikola S. Vukelić; Milena S. Dimitrijević; Zvezdana Baščarević; Sandra Kurko; Ljiljana Matović
Ceramics International | 2014
Violeta Nikolić; Miroslav Komljenović; Nataša Marjanović; Zvezdana Baščarević; Rada Petrović
Construction and Building Materials | 2014
Nataša Marjanović; Miroslav Komljenović; Zvezdana Baščarević; Violeta Nikolić
Construction and Building Materials | 2013
Miroslav Komljenović; Zvezdana Baščarević; Nataša Marjanović; Violeta Nikolić
Construction and Building Materials | 2015
Violeta Nikolić; Miroslav Komljenović; Zvezdana Baščarević; Nataša Marjanović; Zoran Miladinović; Rada Petrović
International Journal of Hydrogen Energy | 2011
Sandra Kurko; Željka Rašković; Nikola Novaković; Bojana Paskaš Mamula; Zoran Jovanovic; Zvezdana Baščarević; Jasmina Grbović Novaković; Ljiljana Matović