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Title:Dijagnosticiranje uzroka degradacije šupljih opečnih blokova ugrađenih u stropnu armiranobetonsku konstrukciju
Authors:ID Lubej, Samo (Author)
ID Lutar, Boris (Author)
Files:.pdf Elektronicki_casopis_gradevinskog_fakulteta_Osijek_2013_Lubej,_Lutar_Dijagnosticiranje_uzroka_degradacije_supljih_opecnih_blokova_ugrade.pdf (915,10 KB)
MD5: A78EE2DB6DBC8929AFA8FAA548FBA002
 
URL http://e-gfos.gfos.hr/app/storage/protected/42-09-06-2017-12-09-31-lubej-lutar.pdf
 
Language:Croatian
Work type:Scientific work
Typology:1.01 - Original Scientific Article
Organization:FGPA - Faculty of Civil Engineering, Transportation Engineering and Architecture
Abstract:U konstrukciji montažnih stropova od šupljih opečnih blokova, koji su element ispune između nosivih armiranobetonskih greda, u razdoblju od četiri godine poslije njihove izgradnje došlo je do znatnih oštećenja. Oštećenja stropova manifestirala su se odlamanjem dijelova šupljih opečnih blokova, što je ugrožavalo sigurnost ljudi. Uporabom optičkog mikroskopa i elektronskog mikroskopa, kao i kemijske mikroanalize EDS (Energy Dispersive System), analizirana je oštećena keramika te je utvrđena prisutnost iskristalizirane soli. EDS analizom utvrđena je prisutnost kemijskih elemenata (Al i S), koji uz utvrđenu morfologiju kristala ukazuju na mogućnost prisutnosti minerala etringita (Al2O33CaSO4 x 32H2O). Numeričkom analizom uz primjenu metode konačnih elemenata, uporabom računalnog programa COSMOS Design STAR 3.0 od SRAC (Structural Research and analisis Corporation USA), procijenjen je utjecaj temperaturnih opterećenja na koncetraciju naprezanja na vrhu mikropukotina i na njihovo širenje. U numeričkoj analizi eksperimentalno su uzeta u obzir određena fizikalno- mehanička svojstva materijala. Analizirani su primjeri šupljih opečnih blokova s prisutnošću bijelih kristala i bez njih. Prikazan je raspored faktora sigurnosti po modelu u odnosu na Mises-ovu hipotezu razaranja. Rezultati eksperimentalnih i numeričkih istraživanja pokazali su da kemijska degradacija šupljih opečnih blokova, u kombinaciji s temperaturnim opterećenjem koje nastaje zbog promjena klimatskog režima, može uzrokovati takva oštećenja te da je time ugrožena i sigurnost konstrukcije.
Keywords:votle glinene opeke, mikrostrukture, zapoznelo oblikovanje entringita, mehanske lastnosti, termične analize
Publication status:Published
Publication version:Version of Record
Year of publishing:2013
Number of pages:str. 96-107
Numbering:št. 6
PID:20.500.12556/DKUM-50444 New window
ISSN:1847-8948
UDC:691
ISSN on article:1847-8948
COBISS.SI-ID:17036054 New window
NUK URN:URN:SI:UM:DK:0XCTPD9Y
Publication date in DKUM:10.07.2015
Views:1644
Downloads:541
Metadata:XML DC-XML DC-RDF
Categories:Misc.
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Record is a part of a journal

Title:E-GFOS
Publisher:Sveučilište Josipa Jurja Strossmayera u Osijeku, Građevinski fakultet
ISSN:1847-8948
COBISS.SI-ID:5703009 New window

Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:10.07.2015

Secondary language

Language:English
Title:Diagnosing the causes of clay hollow bricks degradation embedded in the reinforced concrete ceiling
Abstract:Over a two-year period following the construction completion extensive damage has occurred in the mountable brick ceilings at the University of Maribor administrative quarters. The damage of the ceilings consisted in falling pieces of brick filling - construction ceramics, which presented a potential hazard to people. Using the optical as well as electronic microscope methods combined with chemical analysis EDX (Energy Dispersive X-Ray Analysis) we confirmed the presence of the white crystals, which could be mineral ettringite (Al2O33CaSO4 x 32H2O) that can, when present in construction ceramics, cause degradation of matter through expansion. By means of numerical analysis using final elements method and by means of the COSMOS Design STAR 3.0 computer software (by SRAC - Structural Research and Analysis Corporation USA) we were able to experimentally determine effects of temperature fluctuation. The experimentally assessed physical-mechanical characteristics of the material were considered in the numerical analysis. Both cases, brick filling containing the white crystals and brick filling without white crystals were analysed. The safety factor distribution on the model according to Mises demolition hypothesis was shown. It was confirmed on basis of experimental research that the chemical degradation of construction ceramics combined with temperature fluctuation due to climate changes, even without considering degradations due to technological production process, can lead to such damage in the material as to cause a safety hazard.
Keywords:clay hollow bricks, microstructure, delayed ettringite formation, mechanical properties, thermal analysis


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