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1

Próba identyfikacji bentonitu w betonie ściany szczelinowej

Czopowska-Lewandowicz M.

Materiały Budowlane

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2016

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nr 8

67--69

PL

W artykule przedstawiono próbę identyfikacji cząstek bentonitu w strukturze betonu pochodzącego ze ściany szczelinowej. Celem badań było wykazanie, iż podczas wykonywania ścian szczelinowych dochodzi do wymieszania zawiesiny bentonitowej z mieszanką betonową, co powoduje znaczne pogorszenie parametrów technicznych betonu. Wyróżnienie cząstek bentonitu w betonie potwierdziłoby tę tezę. Oznaczenia przeprowadzono na próbkach pobranych z istniejącego obiektu. Po odpowiednim przygotowaniu zostały one poddane badaniu elektronowym mikroskopem skaningowym. Do określenia ilościowego składu fazowego wykorzystano metodę dyfrakcji rentgenowskiej. Przeprowadzono również oznaczenie termograwimetryczne (TG) oraz termicznej analizy różnicowej (DTG) i (DTA). W badanych próbkach nie stwierdzono obecności bentonitu. Podjęto też próbę wykrycia bentonitu w betonie. Oznaczenie przeprowadzono metodami (TG), (DTA) i (DTG). Przeprowadzone badania wykazały, że niewielka (kilkuprocentowa) zawartość bentonitu w betonie nie jest możliwa do wykrycia wymienionymi metodami badawczymi. Obecność bentonitu w monolicie ścian szczelinowych można zatem potwierdzić jedynie na podstawie badań właściwości technicznych betonu.

EN

The article presents an attempt to identify the particles of bentonite in the concrete structure derived from the diaphragm wall. The aim of the research was to demonstrate that during the performance of diaphragm walls, bentonite suspension is mixed with the concrete mix – what causes the significant decrease in technical concrete parameters. The distinction of bentonite particles in the concrete would confirm the above thesis. Markings were carried out on samples taken from the existing object. After appropriate preparation samples were subjected to scanning electron microscope test and quantitative phase composition test using X-ray diffraction method. The thermogravimetry marking (TG) as well as the differential thermal analysis (DTG) and (DTA) were also performed. The presence of bentonite in the tested samples was not stated. Then, an attempt was made to determine the detection of bentonite in the concrete. The marking was performed using (TG), (DTA) and (DTG) methods. The conducted research indicated that a slight (a fewpercent) bentonite content in the concrete is not possible to the detection by the presented research methods. The presence of bentonite in the monolith of the diaphragm walls can therefore be stated only symptomatically on the basis of the technical characteristics research of concrete.

2

Autoclaved aerated concrete with an addition of waste from semi-dry flue gas desulfurization process – thermal stability and XRD investigations

Plaskacz-Dziuba M., Cichosz M., Igliński B., Buczkowski R.

Czasopismo Techniczne. Budownictwo

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2015

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Y. 112, iss. 4-B

123--130

EN

The article presents the results of research on autoclaved aerated concrete (AAC) produced according to the manufacturer recipe and modified AAC with the addition of waste from the semi-dry flue gas desulfurization installation. Produced cubes of concrete were analysed using thermogravimetry in a temperature regime of 0–1200°C in order to determine thermal stability. Samples were also tested using X-ray diffractometer to determine the differences in the content of tobermorite 1.1 nm, the compound which is responsible for the mechanical properties of tested concrete.

PL

W artykule przedstawiono wyniki badań autoklawizowanego betonu komórkowego (ABK ) wyprodukowanego według przepisu producenta oraz zmodyfikowanego ABK z dodatkiem odpadu z instalacji odsiarczania spalin metodą półsuchą. Wyprodukowane kostki betonu poddano analizie termicznej w reżimie temperaturowym 0–1200°C w celu określenia stabilności termicznej oraz badaniu dyfraktometrem rentgenowskim w celu określenia różnic w zawartości tobermorytu 1.1 nm, składnika odpowiedzialnego za parametry wytrzymałościowe betonu komórkowego.

3

Applicability of Dynamic Mechanical and Thermal Methods in Investigation of Ageing Processes of Double Based Rocket Propellants

Matečić-Mušanić S., Sućeska M., Bakija S.

Central European Journal of Energetic Materials

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2007

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Vol. 4, nr 1-2

45-65

EN

Ageing of double based rocket (DBR) propellants, as a consequence of chemical decomposition reaction, as well as physical processes (migration of low molecular constituents: plasticizers, etc.) has significant influence on their relevant properties (e.g. decrease of molar mass of nitrocellulose, decrease of stabiliser content, decrease of specimen mass, change of mechanical and thermal properties, etc.). The change of relevant properties of DBR propellants limits their safe and reliable service life. Even more, under certain conditions decomposition of a DBR propellant may become autocatalytic, which can lead to self-ignition of the DBR propellant. Because of that, it is very important to find out reliable methods for determination of propellant stability at a given moment of time, as well as to predict self-ignition probability under given conditions. In this work we studied dynamic mechanical and thermal properties of DBR propellants artificially aged for different period of time at 90 C, in order to detect and quantify changes in dynamic mechanical and thermal properties that can be used in the propellants stability assessment. Dynamic mechanical properties were studied by dynamic mechanical analysis (DMA), while thermal properties were studied using differential scanning calorimetry (DSC) and thermogravimetry (TGA). The obtained results showed that the ageing caused significant changes of DMA, DSC and TGA curves' shape. The changes are quantified by some of characteristic points on DMA, DSC and TGA curves. It was found out that the most sensitive parameters/characteristic points to the ageing process at DMA curves are: storage modulus at 25 C, storage modulus at softening region, peak width and height on loss modulus curve, glass transition temperature, loss modulus at viscoelastic region, tanδ maximum at viscoelastic region, while the most sensitive parameters at DSC and TGA curves are: peak height and width, heat of reaction, max. heat flow rate, mass loss at a given time, and rate of mass loss at a given time.