In Situ Observation Microstructure Character Changes in the Carbonation Process of Hardened Cement Paste Using ESEM/EDS

Abstract:

Environmental Scanning Electron Microscope (ESEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to in situ observation microstructure character changes of hardened cement paste due to carbonation. Three types water-to-cement ratio of 0.53, 0.35 and 0.23 were research. When w/c=0.53, Carbonation enlarged the cracks, and some calcium carbonate spots appear on the calcium hydroxide crystals. When w/c=0.35, less cracks appear, and some white flocculent calcium carbonated appear on the calcium hydroxide crystals than above w/c=0.53 cement paste. When w/c=0.23, the microstructure character before and after carbonation have distinct changes, and some cracks become small or disappeared. Unhydrated cement clinkers continue to hydrate reactions and there are many white SiO₂•nH₂O (silica gel) after C-S-H gel carbonation in cement paste matrix.

• Periodical: Advanced Materials Research (Volumes 194-196)
• Pages: 873-877
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.194-196.873
• Online since: February 2011
• Authors: Jian De Han, Gang Hua Pan, Wei Sun
• Keywords: Carbonation, Cement Paste, ESEM/EDS, Microstructure

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