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Gibas K.,Instytut Podstawowych Problemow Techniki | Glinicki M.,Instytut Podstawowych Problemow Techniki | Nowowiejski G.,Hydrobudowa 1 Betoniarnia Laboratorium Sp Z Oo
Road and Bridges - Drogi i Mosty | Year: 2013

The paper presents the investigation of concrete resistance to penetration by liquid and gaseous environmental media. Calcareous fly ash obtained from Bełchatów Power Station was used as concrete additive. In the mix design a certain portion of binder (15% and 30%) was substituted with calcareous fly ash assuming the efficiency factors of 0.7 or 1.0. The tested parameters included the air permeability coefficient measured with Torrent method, the depth of water penetration under pressure and the coefficient of chloride ions migration measured with the rapid chloride migration test. It was established that the addition of calcareous fly ash resulted in the desired reduction of the value of a chloride migration coefficient while the effect on the permeability of water and air was similar to the effect it had on the compressive strength of concrete.

Glinicki M.,Instytut Podstawowych Problemow Techniki | KrzywobLocka-Laurow R.,Instytut Techniki Budowlanej | Ranachowski Z.,Instytut Podstawowych Problemow Techniki | Dabrowski M.,Instytut Podstawowych Problemow Techniki | WoLowicz J.,Instytut Podstawowych Problemow Techniki
Road and Bridges - Drogi i Mosty | Year: 2013

The investigation of concrete microstructure and phase composition was performed on concrete specimens produced with and without calcareous fly ash obtained from Bełchatów Power Station. The used calcareous fly ash (designated W) was either unprocessed or ground to assumed specific surface and added to concrete mix to substitute 3 0% of the binder by weight. The following testing methods were used in this research: scanning electron microscopy, differential thermal analysis (DTA) and multiple microindentation. The characteristic features of the investigated microstructures are discussed and the effect of calcareous fly ash on the content of non-evaporable water and portlandite in cement matrix is analysed. The results of microindentation and compressive strength testing were used as the basis for evaluation of the efficiency of calcareous fly ash added to concrete mix.

Jozwiak-Niedzwiedzka D.,Instytut Podstawowych Problemow Techniki | Tucholski Z.,Instytut Historii Nauki
Drogi i Mosty | Year: 2010

In the paper the history of a viaduct from Railway Warsaw - Kalisz and its present condition is described. The parabolic vaulted viaduct that was built for the Railway Warsaw - Kalisz, is probably one of two oldest concrete structures in Warsaw. The quality of concrete specimens taken from parabolic vaulted viaduct is analyzed and the preparation of thin sections is described. The analysis of impregnated this sections was performed using transmitted polarized light, crossed polarized light and fluorescent light. The petrographic analysis of aggregate was conducted and the grain shape and grain size distribution is described. The paste quality was also analyzed and water-cement ratio of concrete taken from viaduct was determined in UV light. The results of thin section analysis showed that this over 100 years old structure was made from two different concretes: "old concrete" and "new concrete". "Old concrete" was cast in 1904, and "new concrete"-probably between First and Second World War as a part of some kind of repair works.

In the paper two algorithms of the machine learning are used in order to determine the durability of concrete modified with circulating fluidized bed combustion (CFBC) ash from hard coal and from brown coal. The rapid chloride permeability test, according to Nordtest Method BUILD 492, was used for determining the chloride ions penetration in concrete. The frost salt scaling tests were performed according to the Swedish Standard method SS 137244. In both cases the performed tests provided databases used as training sets to generate the rules describing the relations between material composition and durability parameters. The rules generated by computer programs AQ21 and WEKA using J48 algorithm provided means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials of good and acceptable resistance to chloride penetration as well as materials resistant or not resistant to the surface scaling caused by freezing cycles.

Ranachowski P.,Instytut Podstawowych Problemow Techniki | Rejmund F.,Instytut Podstawowych Problemow Techniki | Ranachowski Z.,Instytut Podstawowych Problemow Techniki | Pawelek A.,Polish Academy of Sciences | Piatkowski A.,Polish Academy of Sciences
Przeglad Elektrotechniczny | Year: 2010

The paper presents mechanoacoustic and microscopic testing of degradation processes of modern C 120 electrotechnical porcelain of domestic medium voltage line insulator. Samples of small dimensions, cut off from the rod of insulator, were subjected to compressive loading, with recording of acoustic emission descriptors. Microscopic analysis enabled determining the advancement of degradation effects. Results of experiments revealed high long-term mechanical resistance of tested material, when compared to typical C 120 porcelains.

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