Martina Havelcová

The presented article studies a metakaolin-based geopolymer matrix for which two types of non-recyclable automotive glass waste (AGW) have been used as an alternative aggregate. Their composition and character, as well as their influence on the properties and structure of geopolymer composites (AGW-Gs), have been investigated by means of X-ray fluorescence and X-ray diffraction analyses, scanning electron microscopy, Fourier transform infrared spectrometry and gas chromatography/mass spectrometry. Infrared analysis has proven that the use of AGW does not affect the formation of geopolymer bonds. GC/MS analysis has revealed the presence of triethylene glycol bis(2-ethylhexanoate) in AGW and geopolymers, whose concentration varied according to the size of the fractions used. Preliminary compressive-strength tests have shown the promising potential of AGW-Gs. From the presented results, based on the study of two types of automotive glass waste, it is possible to assume that automotive glass will generally behave in the same or a similar manner in metakaolin-based geopolymer matrices and can be considered as potential alternative aggregates. The result is promising for the current search for new sources of raw materials, for ensuring resource security, for the promotion of sustainability and innovation and for meeting the needs of the growing world population while reducing dependence on limited resources.

Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Piedmont Basin (Czech Republic) were described and characterized petrologically and mineralogically. The Permian sediments originated from weathering products in metasediments and granitoids of the Krkonoše–Jizera and Orlice–Sněžník crystalline complexes. The organic matter contained up to 4.8 wt.% uranium, as uraninite grains. Elements associated with uraninite, such as Pb, Zr, Cu, and As, may have accumulated from epigenetic fluids in layers rich in organic matter during their late diagenesis. The bitumen structures were extremely heterogeneous, a feature attributed to the radiolytic effects of uranium. Amorphous bitumens, alternating with various forms of nodular and corroded bitumen types from multiple generations, were present. Low and highly altered bitumens with weak anisotropy were recognized, together with halo zones, with reflectance up to 4.37%. The halo zones differed in size, brightness, and reflectance, increasing from the edge to the center. Halos often revealed dark rims between uraninite inclusions and clear zones, originating probably as a result of weaker alterations in organic matter due to the presence of other inorganic components. Uranium concentration was the main factor controlling the degree of radiolytic alteration. The studied uraniferous bitumens are an excellent example of multistage formation and diverse evolution during burial and diagenesis.

Opening of the Blanka Tunnel Complex (BTC) in Prague, Czech Republic, the longest city tunnel in Europe, significantly increased traffic on a connected main road, the V Holešovičkách street (VHS). To study environmental changes in VHS connected with BTC opening, sampling of road dust and airborne particulate matter in the VHS vicinity started 3 years before BTC opening and continued until BTC pilot operation. The enrichment factors calculated for the collected samples from elemental compositions determined by instrumental neutron activation analysis (INAA) have shown significant enrichment for Se, Sb, Hg, Br, Mo, Zn, As, W, Cr, Ba, and Fe, but not their increase after starting BTC operation. The Principal Component Analysis allowed distinguishing between detrital and anthropogenic, probably traffic related, origin of the elements determined in samples. The study demonstrated a potential of INAA for multielement trace analysis of minute samples (28 elements determined in samples down to 20 μg, with detection limits down to sub-ng level) and its application in urban geochemistry studies.

Oils, e.g. linseed oil, has been used as mortar admixtures or components of lime-oil mastic since ancient times. The reason was either to increase the mortar durability and/or to prolong the mortar/mastic workability. Historic mortars are conventionally analyzed by means of X-ray diffraction and thermal analysis, but these methods are not able to detect the organic compounds directly. The goal of the present research was to evaluate the applicability of thermal analysis, infra-red spectroscopy, solid state NMR spectroscopy and gas chromatography for detection and possible quantification of linseed oil in prepared mortar containing, beyond the oil, just lime and calcite. Both applied spectroscopies were able not only detect the presence of oil but may be used also for study of the oil chemical transformation in the alkaline environment of the lime mortar. Thermal analysis is not able to identify kind of organic admixture, but when it is known that it is e.g. linseed oil, its quantification by help of Evolved Gas Analysis is very good. The results of gas chromatography of mortar’s extract are affected by the polymerization of oil in mortar. The total organic content analysis is providing good information about the total amount of organics in mortar. There in not any single method, which could provide all information about the oil admixture in mortar (kind of oil, content of oil, fate of oil after mortar’s mixing) by itself; the combination of techniques must be used.