•Characterization of slag derived from stainless steelmaking refining processes.•Secondary stainless steel slag contain hydraulic phases, predominantly calcium aluminates.•Study of cement composites ...in which cement is replaced by secondary stainless steel slag.•Investigation of strength development, hydration products, and porosity.•Secondary stainless steel slag is a promising supplementary cementitious material.
Detailed characterization of calcium aluminate rich secondary steel slag derived from two different refining processes of stainless steel production has been performed in order to gain generic knowledge about this by-product, and its behaviour as a supplementary cementitious material. Additionally, slag blended cement composites were investigated and compared to a limestone filler blended cement composites and to a reference cement composites. The results showed that the investigated slag contained several hydraulic phases, mainly in the form of calcium aluminates. In the case of the slag cement composites, a larger proportion of hydration products was observed than in the case of the limestone cement composites, as well as a higher rate of strength increase.
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•Chemical and mechanical properties were studied in cement composites with added ladle slag.•Leachability tests based on diffusion were performed in compact and ground ...composites.•Cr(VI) was immobilized in cement composites with the addition of ladle slag.•To prevent leaching of Mo and Ba, crushing of the composites should be omitted.•The investigated ladle slag can be implemented as supplementary cementitious material.
In the present work compact and ground cement composites in which 30% of cement by mass was replaced by ladle slag were investigated for their chemical and physico-mechanical properties. To evaluate long-term environmental impacts, leachability test based on diffusion, which combined both, diffusion and dissolution of contaminants, was performed in water and saline water. Total element concentrations and Cr(VI) were determined in leachates over a time period of 180days. At the end of the experiment, the mineralogical composition and the physico-mechanical stability of cement composites was also assessed. The results revealed that Cr(III) and Cr(VI) were immobilized by the hydration products formed in the cement composites with the addition of ladle slag. Cr(VI) content originating from the cement was also appreciably reduced by Fe(II) from minerals present in the added ladle slag, which thus had significant positive environmental effects. Among metals, only Mo and Ba were leached in elevated concentrations, but solely in ground cement composites with the addition of ladle slag. Lower V concentrations were observed in leachates of ground than compact composite. It was demonstrated that the presence of ladle slag in cement composites can even contribute to improved mortar resistance. The investigated ladle slag can be successfully implemented in cement composites as supplementary cementitious material.
This study deals with the characterization of mortars collected from bath complex of the Roman
villa rustica from an archeological site near Mošnje (Slovenia). The mortar layers of the mosaics, wall ...paintings and mortar floors were investigated. A special aggregate consisting of brick fragments was present in the mortars studied. The mineralogical and petrographic compositions of the mortars were determined by means of optical microscopy, X-ray powder diffraction and FTIR spectroscopy. Analysis of aggregate–binder interfaces using SEM-EDS revealed various types of reactivity rims. In order to assess the hydraulic characteristics of the mortars, the acid-soluble fractions were determined by ICP-OES. Furthermore, the results of Hg-porosimetry and gas sorption isotherms showed that mortars with a higher content of brick fragments particles exhibited a higher porosity and a greater BET surface area but a lower average pore diameter compared to mortars lacking this special aggregate.
► Mineral and microstructural characterizations of brick–lime mortars. ► Hydraulic character of mortars in Roman baths complex. ► Reaction rims were observed around brick fragments and dolomitic grains. ► Higher content of brick particles yielded a higher BET surface area. ► Addition of brick particles increased porosity and diminished pore size diameter.
Roman pottery excavated from the remains of a villa rustica near Mošnje (Slovenia) was analyzed in terms of its mineralogical and basic geochemical characteristics, to elucidate the technologies of ...manufacture. Selected samples were examined with optical microscopy, X-ray powder diffraction, SEM–EDS and ICP-OES. Results show that the studied pottery samples can be divided into two main groups based on the nature and size of grains; calcite-tempered pottery and pottery containing predominant fine quartz grains. This mineralogical distinction also reflects differences in production technology.
► Mineral composition of Roman pottery. ► Geochemical composition of Roman pottery. ► Roman pottery manufacturing technology.
► Weathering of the black limestone on historical monuments. ► Oxygen and sulfur isotope composition of sulfate salts (outdoors and indoors). ► A data exhibit more scattered δ
34S values with respect ...to δ
18O values.
The black limestone widely used in Slovenian monuments, particularly in the baroque architecture, is deteriorating extensively due to salt crystallization. Samples of soluble salts from two important historical monuments (in Ljubljana, Slovenia) were investigated in terms of their mineral and isotopic (S and O) compositions. Results revealed the presence of gypsum and soluble salts of the MgSO
4·
nH
2O series, such as starkeyite (MgSO
4·4H
2O), pentahydrite (MgSO
4·5H
2O) and hexahydrite (MgSO
4·6H
2O). Whereas black crusts and subflorescences consisted of gypsum, efflorescences appeared to be an assemblage of gypsum and MgSO
4 hydrates. Sample δ
18O
sulfate values varied from −1.9‰ to +5.5‰ vs. V-SMOW and δ
34S
sulfate values from −19.8‰ to +3.2‰ vs. V-CDT. The respective isotopic composition of analysed outdoor and indoor monument samples indicated different sources of contamination.
The purpose of this study was to develop a compatible repair mortar for two lithotypes of Peračica tuff (Slovenia): fine-grained and coarse-grained. Mineralogical–petrographic characterization of ...tuff was carried out via optical microscopy and X-ray powder diffraction, and the relevant physical–mechanical properties of tuff and repair mortars were determined: capillary water absorption, water absorption at atmospheric pressure, open porosity, compressive strength and resistance to salt crystallization. A repair mortar was prepared by mixing crushed Peračica tuff and quartz sand, with different grain size and mass ratios, and ethyl silicate (KSE 500 STE, Remmers) as a binder. The results showed that with an appropriate combination of crushed tuff, quartz sand and ethyl silicate, a compatible repair mortars can be obtained for both lithotypes.
Calcium chromates with the empirical formulas Ca10Cr6−O25, Ca3Cr2O8, and Ca5Cr3O12, which form at temperatures >900°C at CaO:Cr2O3 molar ratios of 3 in an oxidation atmosphere have been synthesized ...in the pure state. X‐ray absorption near‐edge structure (XANES) spectroscopy has been used to determine the average valence state of chromium in the samples. The presence of unusual chromium valence states, 4+ and 5+, which was proposed via X‐ray diffractometry studies, is strongly supported.
The Jezersko meteorite is a newly confirmed stony meteorite found in 1992 in the Karavanke mountains, Slovenia. The meteorite is moderately weathered (W2), indicating short terrestrial residence ...time. Chondrules in partially recrystallized matrix are clearly discernible but often fragmented and have mean diameter of 0.73 mm. The meteorite consists of homogeneous olivine (Fa19.4) and low‐Ca pyroxenes (Fs16.7Wo1.2), of which 34% are monoclinic, and minor plagioclase (Ab83An11Or6) and Ca‐pyroxene (Fs6Wo45.8). Troilite, kamacite, zoned taenite, tetrataenite, chromite, and metallic copper comprise about 16.5 vol% of the meteorite. Phosphates are represented by merrillite and minor chlorapatite. Undulatory extinction in some olivine grains and other shock indicators suggests weak shock metamorphism between stages S2 and S3. The bulk chemical composition generally corresponds to the mean H chondrite composition. Low siderophile element contents indicate the oxidized character of the Jezersko parent body. The temperatures recorded by two‐pyroxene, olivine‐chromite, and olivine‐orthopyroxene geothermometers are 854 °C, 737–787 °C, and 750 °C, respectively. Mg concentration profiles across orthopyroxenes and clinopyroxenes indicate relatively fast cooling at temperatures above 700 °C. A low cooling rate of 10 °C Myr−1 was obtained from metallographic data. Considering physical, chemical, and mineralogical properties, meteorite Jezersko was classified as an H4 S2(3) ordinary chondrite.
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