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1.
Why are the Early Gothic murals in St. Jacob’s Church in Ormož, Slovenia, almost entirely black?
Anabelle Križnar, Katja Kavkler, Sabina Dolenec, 2024, original scientific article

Abstract: In St. Jacob’s parish church in Ormož, Slovenia, mural paintings from around 1350–1370 are partially conserved in the northeastern corner of the main nave. They are almost completely black, indicating a large-scale pigment degradation. They were studied as a part of a larger research project aiming to identify materials applied and their possible degradation. First, they were studied in situ, and next, extracted samples of plaster, pigments, and colour layers were analysed by optical microscopy, Raman spectroscopy, FTIR spectroscopy, SEM-EDS, and XRD. Haematite, green earth, malachite, azurite, and tenorite were identified, showing that azurite and perhaps also malachite degraded to black tenorite, probably due to their fine grinding and their application directly on the fresh plaster. The plaster is made with small and large amounts of aggregate with mostly quartz with some impurities, which makes it fragile. The original appearance of these murals was of bright blue and green colours.
Keywords: mural painting, medieval painting, Gothic art, St. Jacob's Church, Ormož, Slovenia, pigments, chemical structure, colour degradation, optical microscopy, Raman microspectroscopy, FTIR, XRD
Published in DiRROS: 17.04.2024; Views: 37; Downloads: 11
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3.
Construction materials for a sustainable future : proceedings of the 2nd International Conference CoMS 2020/21
2021, proceedings of peer-reviewed scientific conference contributions (international and foreign conferences)

Abstract: Zbornik pokriva številne, predvsem tehnične teme, ki so pomembne za trajnostni razvoj gradbenega sektorja, kot ključnega dejavnika pri doseganju ciljev EU za obvladovanje podnebnih sprememb in za prehod v brezogljično družbo. Vsebinsko naslavlja inovacije v gradbenih materialih in tehnologijah, vključno s komponentami za zdravo in udobno bivanje, ter interakcije med materiali in okoljem. Poleg energetske učinkovitosti stavb je v njem zajeto področje širšega razumevanja trajnostnega načrtovanja, gradnje in vzdrževanja stavb ter monitoring, ocenjevanje in modeliranje stavb. Vključuje pa tudi vsebine, ki se nanašajo na krožno gospodarstvo, kot je recikliranje materialov in komponent ter koncepti sanacij stavb, ter na digitalizacijo in avtomatizacijo področja.
Keywords: trajnostno gradbeništvo, trajnostna gradnja, gradbeni materiali, tehnologije, energetska učinkovitost, zborniki, elektronske knjige
Published in DiRROS: 25.01.2024; Views: 178; Downloads: 71
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4.
Construction materials for a sustainable future : proceedings of the 2nd International Conference CoMS 2020/21
2021, proceedings of peer-reviewed scientific conference contributions (international and foreign conferences)

Keywords: trajnostno gradbeništvo, trajnostna gradnja, gradbeni materiali, tehnologije, energetska učinkovitost, zborniki, elektronske knjige
Published in DiRROS: 22.01.2024; Views: 159; Downloads: 67
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5.
CoMS_2020/21 Construction materials for a sustainable future : 2nd International Online Conference
2021, other monographs and other completed works

Keywords: trajnostno gradbeništvo, trajnostna gradnja, gradbeni materiali, tehnologije, energetska učinkovitost, zborniki, elektronske knjige
Published in DiRROS: 22.01.2024; Views: 177; Downloads: 71
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6.
Manual for use of Al-containing residues in low-carbon mineral binders
Sabina Dolenec, Katja Malovrh Rebec, Anja Lešek, Katarina Šter, Lea Žibret, Gorazd Žibret, Klemen Teran, Emil Pučko, Ildikó Merta, Bojan Poletanovic, Elena Yaneva, Peter Kesserű, Ildikó Kovács, Bence Kószó, Alexandra Németh, Richard Laucournet, Mustafa Hadžalić, Emilija Fidanchevski, Biljana Angjusheva, Vojo Jovanov, Miloš Nenadović, Snežana B. Nenadović, Ivana Vukanac, Liljana Kraljević, Mojca Loncnar, Andrej Ipavec, 2020, dictionary, encyclopaedia, lexicon, manual, atlas, map

Abstract: Današnje družbe si ni več mogoče predstavljati brez sodobne infrastrukture, ki temelji na uporabi različnih materialov ter zahteva veliko porabo energije. Vzporedno s proizvodnjo materialov, nastajajo ogromne količine različnih industrijskih in rudarskih ostankov (odpadki/stranski proizvodi), ki jih trenutno ne izkoriščamo, sama odlagališča pa so premalo raziskana. Cilj Evropske unije (EU) je povečati učinkovito rabo virov in ponudbo sekundarnih surovin z recikliranjem, popisom odpadkov iz rudarskih in drugih industrijskih dejavnosti ter njihova ponovna uporaba. Veliko industrijskih in rudarskih odpadkov je obogatenih z aluminijem (Al), zato lahko nadomeščajo naravne vire Al v mineralnih veznih, vendar njihova uporaba zahteva obsežno poznavanje njihovih kemijskih, mineraloških, radioloških in fizikalnih lastnosti. Priročnik, ki so ga pripravili partnerji projekta RIS-ALiCE obravnava zakonodajne vidike, ki urejajo uporabo sekundarnih surovin v gradbenih proizvodih, opis najpogostejših industrijskih in rudarskih ostankov, ki vsebujejo Al (nahajališča boksitov, rdeče blato, jeklarske žlindre, pepeli iz različnih industrij, itd.), potencial njihove ponovne uporabe in njihov ekonomski vidik, potencialne zahteve/ovire za uporabo sekundarnih surovin v cementni industriji in opis belitno-sulfoaluminatnih cementov, ki so obetavna rešitev za izvajanje krožnega gospodarstva z uporabo velikih količin odloženih industrijskih in rudarskih odpadkov, bogatih z Al.
Keywords: gradbeni proizvodi, ponovna uporaba, ekonomski vidik, industrija cementa, krožno gospodarstvo, industrijski odpadki, zakonodaja, elektronske knjige
Published in DiRROS: 22.01.2024; Views: 196; Downloads: 78
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7.
Use of steel slag for the synthesis of belite-sulfoaluminate clinker
Lea Žibret, Martina Cvetković, Maruša Mrak, Mojca Loncnar, Andrej Ipavec, Sabina Dolenec, 2020, published scientific conference contribution

Abstract: Belite-sulfoaluminate (BCSA) cements are low-carbon mineral binders, which require low energy consumption and allow the incorporation of various secondary raw materials in the clinker raw meal. In this study two types of unprocessed steel slags, coming from stainless steel production, were incorporated in the BCSA clinkers. The clinker phase composition, clinker reactivity, and the compressive strength of the cement were studied to evaluate the possible use of the slag in BCSA clinkers. The cement clinkers were synthesized by using natural raw materials, white titanogypsum, mill scale, as well as two different steel slags: (i) EAF S slag, which is a by-product of melting the recycled steel scrap in an electric arc furnace, and (ii) la dle slag as a by-product of the processes of secondary metallurgy, in various quantities. Raw mixtures with two different targeted phase compositions varying in belite, calcium sulfoaluminate and ferrite phases were sintered at 1250 °C. Clinker phases were determined by Rietveld quantitative phase analysis, while their distribution, morphology and incorporation of foreign ions in the phases were studied by SEM/EDS analysis. The clinker reactivity was determined by isothermal calorimetry. BCSA cements were prepared by adding titanogypsum. The compressive strength of the cement pastes was determined after 7 days of hydration. The presence of a predicted major clinker phases was confirmed by Rietveld analysis, however periclase was also detected. Microscopy revealed subhedral grains of belite and euhedral grains of calcium sulfoaluminate phases, while ferrite occurred as an interstitial phase. The results showed differences in the microstructure and reactivity of the clinker and cement, which can be attributed to varying amounts of ettringite due to different slag types
Keywords: belite-sulfoaluminate cement, cement clinker, steel slags, clinker microstructure, cement reactivity
Published in DiRROS: 19.01.2024; Views: 166; Downloads: 74
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8.
Construction materials for a sustainable future : proceedings of the 2nd International Conference CoMS 2020/21
2020, proceedings of peer-reviewed scientific conference contributions (international and foreign conferences)

Abstract: Zbornik pokriva številne, predvsem tehnične teme, ki so pomembne za trajnostni razvoj gradbenega sektorja, kot ključnega dejavnika pri doseganju ciljev EU za obvladovanje podnebnih sprememb in za prehod v brezogljično družbo. Vsebinsko naslavlja inovacije v gradbenih materialih in tehnologijah, vključno s komponentami za zdravo in udobno bivanje, ter interakcije med materiali in okoljem. Poleg energetske učinkovitosti stavb je v njem zajeto področje širšega razumevanja trajnostnega načrtovanja, gradnje in vzdrževanja stavb ter monitoring, ocenjevanje in modeliranje stavb. Vključuje pa tudi vsebine, ki se nanašajo na krožno gospodarstvo, kot je recikliranje materialov in komponent ter koncepti sanacij stavb, ter na digitalizacijo in avtomatizacijo področja.
Published in DiRROS: 19.01.2024; Views: 161; Downloads: 42
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9.
Effect of the cooling regime on the mineralogy and reactivity of belite-sulfoaluminate clinkers
Sabina Dolenec, Katarina Šter, Maruša Mrak, Klara Žagar, Andrej Ipavec, Lea Žibret, 2020, original scientific article

Abstract: This study investigated the influence of different cooling regimes on the microstructure and consequent reactivity of belite-sulfoaluminate clinkers. The cement clinkers were synthesized by incorporating secondary raw materials, such as titanogypsum and bottom ash, to the natural raw materials. Clinker phases were determined by Rietveld quantitative phase analysis, while the distribution morphology and the incorporation of substitute ions in the phases were characterized by scanning electron microscopy using energy-dispersive X-ray spectroscopy (SEM/EDS). Clinker reactivity was studied using isothermal calorimetry and was additionally investigated through compressive strength, which was determined for the cement prepared from the synthesized clinkers. X-ray diffraction analysis showed that, as well as the three main phases (belite, calcium sulfoaluminate, and ferrite), the clinkers contained additional minor phases (mayenite, gehlenite, arkanite, periclase, and perovskite), the ratios of which varied according to the cooling regime utilized. Microscopic observations indicated that the cooling regime also influenced the crystal size and morphology of the main phases, which consequently affected clinker reactivity. Furthermore, a smaller amount of substitute elements was incorporated in the main phases when cooling was slowed. Results showed that, in comparison to clinkers cooled at slower rates, air quenched clinkers reacted faster and exhibited a higher compressive strength at 7 days.
Keywords: clinkers, belite, calcium sulfoaluminate, cooling, microstructure, reactivity
Published in DiRROS: 20.12.2023; Views: 170; Downloads: 71
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10.
Raman microspectroscopy of garnets from Sfibulae from the archaeological site Lajh (Slovenia)
Saša Kos, Matej Dolenec, Judita Lux, Sabina Dolenec, 2020, original scientific article

Abstract: Garnets (19 pieces) of Late Antique S-fibulae from the archaeological site at Lajh-Kranj (Slovenia) were analysed with Raman microspectroscopy to obtain their mineral characteristic, including inclusion assemblage. Most garnets were determined as almandines Type I of pyralspite solid solution series; however, three garnets showed a higher Mg, Mn and Ca contents and were determined as almandines Type II. Most significant Raman bands were determined in the range of 169–173 cm−1 (T(X2+)), 346–352 cm−1 (R(SiO4)), 557–559 cm−1 (ν2), 633–637 cm−1 (ν4), 917–919 cm−1 (ν1), and 1042–1045 cm−1 (ν3). Shifting of certain Raman bands toward higher frequencies was the result of an increase of the Mg content in the garnet composition, which also indicates the presence of pyrope end member in solid garnet solutions. Inclusions of apatite, quartz, mica, magnetite, ilmenite, as well as inclusions with pleochroic or radiation halo and tension fissures (zircon), were found in most of the garnets. Rutile and sillimanite were found only in garnets with the highest pyrope content. Spherical inclusions were also observed in two garnets, which may indicate the presence of melt or gas residues. The determined inclusion assemblage indicates the formation of garnets during medium- to high-grade metamorphism of amphibolite or granulite facies. According to earlier investigations of the garnets from Late Antique jewellery, the investigated garnets are believed to originate from India.
Keywords: garnets, inclusions, Sfibulae, Late Antiquity, provenance, Raman microspectroscopy, XRF spectroscopy
Published in DiRROS: 20.12.2023; Views: 150; Downloads: 131
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