Microstructure of Tricalcium Silicate and Portland Cement Systems at Middle Periods of Hydration-development of Hadley Grains

The development of the microstructure of C(sub)3S paste and a Portland cement paste was studied between 7 and 24 h by means of backscattered electrons in a field-emission SEM. The course of hydration was measured by isothermal calorimetry. While the abundant occurrence of Hadley grains (hollow-shells) in Portland cement systems is well documented from a number of SEM and other microscopy studies, some earlier reports have noted that Hadley grains do not form in C(sub)3S or alite paste alone. This report shows evidence of Hadley grains in C(sub)3S paste, and follows their development from mid-to-late hydration stages. At around 10 h the microstructure with respect to Hadley grains was seen to develop in a very similar manner in C(sub)3S and cement. In both systems, a narrow gap developed often between the receding anhydrous cores and the layer of reaction product enveloping the cores. After 1 day, Hadley grains had developed only in the cement paste, where they became a prominent feature. Only small ‘hollowed-out’ hydration shells were seen in the C(sub)3S paste after 1 day, and were presumably remnants of the small gapped Hadley grains seen at the earlier hydration stages.

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  • Supplemental Notes:
    • Abstract reprinted with permission from Elsevier
  • Authors:
    • Kjellsen, K O
    • Lagerblad, B
  • Publication Date: 2007-1

Language

  • English

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Filing Info

  • Accession Number: 01042263
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 26 2007 2:38AM