Samo Lubej (Author), Boris Lutar (Author)

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;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UM FGPA - Faculty of Civil Engineering, Transportation Engineering and Architecture
UDC: 691
COBISS: 17036054 Link will open in a new window
ISSN: 1847-8948
Views: 962
Downloads: 343
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Other data

Secondary language: Croatian
Secondary title: Diagnosing the causes of clay hollow bricks degradation embedded in the reinforced concrete ceiling
Secondary 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.
Secondary keywords: clay hollow bricks;microstructure;delayed ettringite formation;mechanical properties;thermal analysis;
URN: URN:SI:UM:
Type (COBISS): Scientific work
Pages: str. 96-107
Issue: ǂBr. ǂ6
Chronology: 2013
ID: 1439584