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Query: "author" (Mladenovič Ana) .

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11.
Leaching and geochemical modelling of an electric arc furnace (EAF) and ladle slag heap
Mojca Loncnar, Ana Mladenovič, Vesna Zalar Serjun, Marija Zupančič, Hans A. van der Sloot, 2022, original scientific article

Abstract: Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composi- tion. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag.
Keywords: EAF slag, field verification, geochemical modelling, ladle slag, leaching, release prediction, steel slag heap
Published in DiRROS: 28.04.2023; Views: 421; Downloads: 218
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12.
Residual compressive behavior of self-compacting concrete after high temperature exposure - influence of binder materials
Marija Jelčić Rukavina, Ivan Gabrijel, Ivanka Netinger Grubeša, Ana Mladenovič, 2022, original scientific article

Abstract: This paper presents an experimental investigation of the compressive behavior of highstrength self-compacting concrete exposed to temperatures up to 600 C. Ten different concrete compositions were tested, in which part of the cement (by weight) was replaced by three different mineral additives (5–15% metakaolin, 20–40% fly ash and 5–15% limestone). The stress–strain curves, compressive strength, modulus of elasticity and strain at peak stress were evaluated from uniaxial compression tests. Scanning electron microscope micrographs were also taken to evaluate the damage caused by the high temperatures. A sharp decrease in mechanical properties and an increase in peak strain were observed already after 200 C for all mixes tested. The different mineral additives used in this study affected the variations of residual compressive strength by 24% and peak strain by 38%, while the variations of residual modulus elasticity were 14%. Comparing the obtained results with the recommendations for compressive strength given in regulatory code EN 1992-1-2 for high strength concrete, it can be concluded that the strength loss observed in EN 1992-1-2 at temperatures up to 400 C is too conservative. The Popovics model for the relationship between stress and strain provided a good approximation for the experimentally determined stress–strain curves at different temperatures.
Keywords: self-compacting concrete, mineral additives, high temperatures, residual mechanical properties, open access
Published in DiRROS: 28.04.2023; Views: 388; Downloads: 188
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