Dalibor Všianský

Cement Microstructures and Durability in Ancient Roman Seawater Concretes

Roman hydraulic maritime concretes of the central Italian coast have pumiceous volcanic ash, or pulvis Puteolanus, from the Bay of Naples as mortar pozzolan. Petrographic and mineralogical analyses of cement microstructures in relict lime, tuff, and pumice clasts suggest that pozzolanic reaction at high pH produced gel-like calcium-aluminum-silica-hydrate cements. Orthorhombic 11 A-tobermorite, with unit cell dimensions a = 5.591(1)A, b = 3.695(1)A, c = 22.86(1)A, developed in the residual cores of portlandite clasts and in certain pumiceous clasts, as well. Ettringite and calcium-chloroaluminate formed in discrete, perimetral microstructures and in the cementitious matrix. Phillipsite and chabazite cements may reflect later dissolution of alkali-rich volcanic glass at pH 9–10. The cement systems have remained stable for 2,000 years, during partial to full immersion in seawater. Vitruvius’ De architectura and other ancient texts describe the raw materials of the concretes, preparation of lime, and construction of submerged wooden forms. Information concerning the materials, formulations, and installations of the concretes was apparently spread by movement of central Italian engineers around the Mediterranean but also, perhaps, by the circulation of sub-literary engineering manuals. Further analytical investigations will determine the diverse chemical processes that produced the cement microstructures, and why the harbour constructions have endured for two millennia.

Lucchesiite, CaFe2+3Al6(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup

Abstract Lucchesiite, CaFe2+3 Al6(Si6O18)(BO3)3(OH)3O, is a new mineral of the tourmaline supergroup. It occurs in the Ratnapura District, Sri Lanka (6°35′N, 80°35′E), most probably from pegmatites and in Mirošov near Strážek, western Moravia, Czech Republic, (49°27′49.38″N, 16°9′54.34″E) in anatectic pegmatite contaminated by host calc-silicate rock. Crystals are black with a vitreous lustre, conchoidal fracture and grey streak. Lucchesiite has a Mohs hardness of ∼7 and a calculated density of 3.209 g/cm3 (Sri Lanka) to 3.243 g/cm3 (Czech Republic). In plane-polarized light, lucchesiite is pleochroic (O = very dark brown and E = light brown) and uniaxial (-). Lucchesiite is rhombohedral, space group R3m, a ≈ 16.00 Å, c ≈ 7.21 Å, V ≈ 1599.9 Å3, Z = 3. The crystal structure of lucchesiite was refined to R1 ≈ 1.5% using ∼2000 unique reflections collected with MoKα X-ray intensity data. Crystal-chemical analysis for the Sri Lanka (holotype) and Czech Republic (cotype) samples resulted in the empirical formulae, respectively: X(Ca0.69Na0.30K0.02)Σ1.01Y(Fe2+1.44Mg0.72Al0.48Ti4+0.33V3+0.02Mn0.01Zn0.01)Σ3.00Z(Al4.74Mg1.01Fe3+0.25)Σ6.00 [T(Si5.85Al0.15)Σ6.00O18](BO3)3V(OH)3W[O0.69F0.24(OH)0.07]Σ1.00 and X(Ca0.49Na0.45□0.05K0.01)Σ1.00Y(Fe2+1.14Fe3+0.95Mg0.42Al0.37Mn0.03Ti4+0.08Zn0.01)Σ3.00Z(Al5.11Fe3+0.38Mg0.52)Σ6.00[T(Si5.88Al0.12)Σ6.00O18] (BO3)3V[(OH)2.66O0.34]Σ3.00W(O0.94F0.06)Σ1.00. Lucchesiite is an oxy-species belonging to the calcic group of the tourmaline supergroup. The closest end-member composition of a valid tourmaline species is that of feruvite, to which lucchesiite is ideally related by the heterovalent coupled substitution ZAl3+ + O1O2- ↔ ZMg2+ + O1(OH)1-. The new mineral was approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA 2015-043).

The Relation of Limestone Origin and its Reactivity to the Preparation of Desulphurization Agents

Limestone is used in the flue gas desulphurization process due to its ability to form sulfur compounds. Different qualities of limestone absorbents can be used in the process and it is therefore important to measure the reactivity of these materials. A limestone with a 90 to 95% of calcium carbonate is used to prepare limestone slurry for the flue gas desulphurization. It is very important to explore the different properties of the raw material for a better understanding of the desulphurization process and also the impact on the economic aspect of the process [1-3]. This article presents a study about limestones reactivity, which is measured by the Bischof-Uhde method. At first the study monitors the impact of the milling of set of Czech limestones on their reactivity and furthermore deals with the influence of the genesis and porosity of the set of world limestones also on the reactivity of limestones in the desulphurization process.

Late Holocene soil processes and the first evidence for ferruginous rhizoconcretions in cool subpolar environments of the Faroe Islands

ABSTRACT The Faroe Islands are characterized by high rates of Holocene geomorphological activity and demonstrable vegetation change, including substantial peat formation. Pedogenesis, especially in the late Holocene, is less well known. Numerous ferruginous rhizoconcretions consisting predominantly of Fe-oxyhydroxides were identified in loam and silty sands in Søltuvík on the island of Sandoy, dated prior to AD 1000. Their formation is related to intensive podzolization and they take the form of the source woody vegetation. The sub-fossil material represents the first evidence for ferruginous rhizoconcretions in the Faroese archipelago.

Organization of ceramic production at a fortified Early Bronze Age settlement in Moravia (Czech Republic) inferred from minimally destructive archaeometry

This paper explores how pottery production was organized at fortified sites of central Europe at the end of the Early Bronze Age. The organization of pottery production in terms of ethnography-based models was inferred jointly by non-destructive multi-elemental analysis, micropetrography and powder X-ray diffraction. This minimally destructive approach was used to explore the mode of pottery production at the fortified central site Blučina (Moravia, Czech Republic). Archaeometry-based indirect evidence indicates that tableware of a specific shape was produced using a specific technology at the site or in its close vicinity and that coarse ware was brought to the site from elsewhere. The results obtained were complexly evaluated and compared with ethnography-based categorizations to reveal the features of production organization of the Early Bronze Age pottery. Multidimensional analysis classified the production as intensified household labour and work of individual retainers, or nucleated corvée, depending on its scale and intensity.

Interregional contacts in the Halaf Period: archaeometric analyses of pottery from Tell Kurdu, Turkey

Dating to the sixth millennium BC, the Halaf Period of northern Mesopotamia has long been considered a time of intense interaction and communication. This claim is based on the remarkable similarity that Halaf Period ceramic styles and especially painted pottery motifs show even over great distances. Analyzed for this paper are a series of potsherds from the contemporaneous levels of the site of Tell Kurdu located in the Amuq Valley of southern Turkey. A range of techniques including X-ray diffraction, wet chemical analysis, scanning electron microscopy and microanalysis, and petrography have been used in order to assess the source materials and to infer evidence for imports. Results show that although painted ceramic motifs at Tell Kurdu are Halaf-like in their general style, they are locally made. Moreover, at least one unpainted sherd may indicate that the sixth millennium inhabitants of Tell Kurdu must also have been involved in an inter-regional trade network. The latter conclusion mirrors similar results by other researchers who have consistently shown that ceramics were regularly traded across northern Mesopotamia in the sixth millennium BC.

Initial Analysis for Study of Pure Limestone Decarbonation

Over the past 70 years dozens of works that deal with the relationship between the properties of limestone, burning modes and properties of lime were created. The expected properties of lime should be proportionate to the nature and burning technology of limestone. But very often the reality is different. General relationships and dependencies have not been found yet. The aim of this work was to determine the relationship among the properties of limestone, lime, hydrated lime. The second aim has been to describe influence of the burning process on the properties of the material mentioned above. For this purpose it was necessary to get a enough wide set of data by performing a comprehensive analysis of various types of limestone. Partial dependencies have been already found on the initial results. An example might be dependence of the samples porosity to decarbonation rate or to its geological age. Due to the realization of this stage of research a coherent set of data was created. This dataset will be used for further research in this area.

Aplikace texturní rtg-difrakční analýzy v tektonice - kvantifikace přednostní orientace kalcitu v karbonátových horninách

Prace je zaměřena na texturni rtg-difrakcni analýzu a jeji využiti v tektonice pro zjisťovani pohybů jemnozrnných hornin a u výchozů, u kterých nejsou zřetelne tektonicke struktury. Material pro analýzu byl odebran z supiny kalcitickeho vapence, u ktereho jsou tektonicke struktury viditelne, aby bylo možne výsledky korelovat se znamou situaci na výchoze

Stavební materiál hradu Špilberk a jeho vývoj

Archeologický a stavebně historický výzkum v ramci rekonstrukce jižniho křidla Spilberku v le - tech 2011–2012 přinesl celou řadu nových poznatků o minulosti hradu. V předkladanem přispěvku využivame ziskana data týkajici se zejmena stavebně technicke keramiky v kombinaci s makroskopickým a mikroskopickým vzorkovanim přirodniho stavebniho materialu. Po konfrontaci se starsimi poznatky nam výsledky umožni sestavit hypotetickou posloupnost vývoje hradu od rane gotiky do barokni přestavby.

Testing of Clay Used for Building a Folk House Replica by Traditional Techniques

The paper describes the mineralogical and petrographic examinations and testing of the mechanical properties of loess and the experimental adobe bricks. The tested material corresponds to a common loess, which was traditionally used in clay buildings in the region. Due both to its composition and mechanical properties it was found to be applicable as a rammed earth building material, and was later used for building a replica of a traditional Moravian folk house at the open-air museum in Strážnice, Czech Republic. The research is part of a cultural heritage documentation and preservation project.