Thermal damage evaluation of full scale concrete columns exposed to high temperatures using scanning electron microscopy and X-ray diffraction

When exposed to elevated temperatures, concrete suffers physicochemical changes, resulting in reduction of mechanical properties, cracking and spalling. These macroscopic changes are related to changes in the microstructure of concrete. In this paper, the microstructure of thermally damaged concrete...

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Bibliographic Details
Published in:Dyna (Medellín, Colombia) Colombia), 2018-10, Vol.85 (207), p.123-128
Main Authors: Fernandes, Bruno, Gil, Augusto Masiero, Bolina, Fabrício Longhi, Tutikian, Bernardo Fonseca
Format: Article
Language:English
Subjects:
altas temperaturas
Coarsening
Columns (structural)
concrete
Coring
Cracking (fracturing)
Damage assessment
difracción de rayos X (XRD)
Electron microscopes
ENGINEERING, MULTIDISCIPLINARY
Fracture mechanics
High temperature
hormigón
Mechanical properties
microestrutura
microscopía electrónica de barrido (SEM)
Microstructure
Morphology
Photomicrographs
ray diffraction (XRD)
Reduction
Reinforced concrete
Scanning electron microscopy
scanning electron microscopy (SEM)
Spalling
X-ray diffraction
x-ray diffraction (XRD)
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Summary:When exposed to elevated temperatures, concrete suffers physicochemical changes, resulting in reduction of mechanical properties, cracking and spalling. These macroscopic changes are related to changes in the microstructure of concrete. In this paper, the microstructure of thermally damaged concrete from real-scale reinforced concrete columns was studied, using scanning electron microscopy (SEM) and x-ray diffraction (XRD). Two real-scale reinforced concrete columns, with different concrete mixtures, were exposed to ISO 834 firestandard curve for 4 hours. After heating, concrete core samples were drilled, sectioned and analyzed in different column section depths.Core samples from reference column not exposed to high temperatures, were also obtained. Macroscopic observations showed a change inthe color of concrete exposed to high temperatures. SEM micrographs presented distinct changes in morphology, like coarsening, and thepresence of cracks and voids. XRD diagrams showed a reduction of portlandite and presence of larnite as depth increases.
ISSN:0012-7353
2346-2183
DOI:10.15446/dyna.v85n207.70593