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Wyszukujesz frazę "rock porosity" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Rock porosity determination in the historical monuments preservation
Autorzy:
Labus, M.
Powiązania:
https://bibliotekanauki.pl/articles/396653.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
porowatość skał
oznaczanie porowatości skał
zabezpieczanie pomników
rock porosity
determination of rock porosity
Opis:
Since ancient times people have used natural stone materials for building purposes. The need of safeguarding historical sites and cultural heritage provoke considering the precise technical characterization of building stones and their changes in weathering processes. In the paper there were listed detailed petrographical analysis used for assessing the quality and durability of the stone material. The porosity properties are detected by means of a range of methods, divided into two groups: direct (including thin section microscopy and scanning electron microscopy), which allow direct documentation and measuring of pore space; and indirect (including mercury porosimetry or nitrogen sorption method), which enable calculating the porosity data from the measuring results. Precise knowledge of porosity characteristics, like total porosity, pore sizes, pore size distribution and pore surface is essential for: stone characterization, modeling of transportation processes, assessment of stone durability, interpretation and prediction of the weathering behavior of natural stones, quantification and rating of stone deterioration and evaluation of effectiveness of stone treatments. Basing on the literature digest and own experience, some examples of the stone porosity characteristic application was presented. The variety of natural stones used as construction material, the complicated nature of weathering processes and complex porosity properties determine implication of different analytical methods for stone examination. The most popular method is mercury porosimetry, but it is worth to remember that a reliable characterization of porosity properties can be guaranteed by application of different analytical procedures.
Źródło:
Civil and Environmental Engineering Reports; 2009, 3; 103-113
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda biplot w interpretacji danych złożonych (CDA) w geologii
The biplot method in Compositional Data Analysis (CDA) in geology
Autorzy:
Labus, K.
Labus, M.
Powiązania:
https://bibliotekanauki.pl/articles/2074772.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
interpretacji danych złożonych
CDA
biplot
skład chemiczny wód podziemnych
porowatość skały
Compositional Data Analysis
rock porosity
groundwater chemical composition
Opis:
Compositional data consist of compositions of parts summing to some whole (e.g.: 100%, 1). Such "closed" data are very popular in geochemistry, sedimentology, hydrogeology and environmetrics. This paper presents the data visualization method by means of the biplot method - a statistical technique widely applied in Compositional Data Analysis. This method enables a graphical display of observations and variables on the same chart, in a way that approximates their correlation. In a biplot the observations are marked with points, and variables - by rays emanating from the origin. Both their lengths and directions are important to the interpretation. The paper presents two examples of implementation of biplots in analysis of hydrogeological and petrological data. The first example concerns petrological data set for pores and skeleton grains of different Polish sandstones. The biplot visualization unveiled a possible independence of subcompositions of transitional pores (T) and macropores (R), as well as submacropores (S) and skeleton grains (Re). The use of this method made it also possible to demonstrate the rule according to which the share of transitive pores decreases at the advantage of real macropores from younger to older rocks, what is related to diagenesis processes. The second example concerns interpretation of hydrological data on chemistry of mine water of the "Rydułtowy" coal mine. In this case the graphical interpretation of biplot revealed large relative variation between HCO3 –-Cl–, HCO3–-I – and HCO3–-Na+. Besides, on the same basis, possible independence between the ion couples: HCO3--Br–, Ca2+-Na+, HCO3–-Cl–, Br-Na+, HCO3–-Cl–and Ca2+-K+ was identified and consequently verified using statistical tests. Additionally, taking into account geometrical features of the relevant biplot, a formula was proposed for defining relationships between shares of ions: Ca2+, Mg2+, Na+ and Cl–<.sup>, SO42–, HCO>sub>3–. These relationships are most apparent for poly-ion groundwater of the active exchange zone, where the ratios of the above mentioned components are similar to each other, despite a slight predominance of SO42– and HCO3– fractions.
Źródło:
Przegląd Geologiczny; 2010, 58, 5; 436-442
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rock pore structure as main reason of rock deterioration
Autorzy:
Ondrášik, M.
Kopecký, M.
Powiązania:
https://bibliotekanauki.pl/articles/178163.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mechanical weathering
rock deterioration
adsorbed water
adsorbed water freezing
rock porosity
freeze-thaw loss
proces zamrażania i rozmrażania
wietrzenie mechaniczne
adsorpcja wody
porowatość skał
Opis:
Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material – concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups – group N in which the pore water does not freeze even when the temperature decreases to –20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.
Źródło:
Studia Geotechnica et Mechanica; 2014, 36, 1; 79-88
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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