Assessment of Concrete Exposed to Elevated Temperatures Using Scanning Electron Microscopy and X-Ray Diffraction

Abstract

The microstructure of concrete subjected to high temperature is studied. The aim of this research is to investigate the potentially use of scanning electron microscopy (SEM) and x-ray diffraction (XRD) in the assessment of thermal damaged concrete. A reinforced column was exposed to ISO 834 fire curve for 4 hours. After heating, core samples were obtained and analyzed. Visual observations showed a change in the color of concrete exposed to high temperatures. SEM micrographs presented distinct changes in morphology, like cracks and voids. XRD diagrams showed a reduction of portlandite and presence of larnite as depth increases. The potential use of these techniques in the estimation of damage in concrete exposed to elevated temperatures was confirmed.